KayPENTAX in the News...Recently Published Studies Involving KayPENTAX Instrumentation

Current postings (see below) include 368 article abstracts that represent a sampling of the recent publications citing our instrumentation.

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Acoustic Analysis

Aerodynamics

Flexible Endoscopes (including Transnasal Esophagoscopes)

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Swallowing

Acoustic Analysis

“Short-Term Effects of Endotracheal Intubation on Voice,” Hamdan, Abdul-Latif, Abla Sibai, Charbel Rameh, and Ghassan Kanazeh, Journal of Voice, Vol. 21 No. 6, pp. 762-768, November 2007.

Summary: The objective of this study was to examine the vocal symptoms and acoustic changes perceived in the short period after endotracheal intubation, and to find the association between these changes and the endotracheal tube parameters. A total of 35 subjects were included. They were examined preoperatively, and 2 and 24 hours postoperatively. The vocal symptoms of hoarseness, vocal fatigue, loss of voice, throat clearing, globus pharyngeus, throat pain, and the acoustic variables mainly average fundamental frequency, relative average perturbation, shimmer, noise to harmony ratio, voice turbulence index, habitual pitch, and maximum phonation time (MPT) were assessed as such and in relation to the following endotracheal tube parameters: duration of anesthesia, number of intubation attempts, size of the tube, cuff volume, cuff mean pressure, and the emergence. The association between anesthesia parameters with incidence of vocal complaints and changes in acoustic parameters were examined using logistic and linear regression. Vocal fatigue was associated significantly with the increase in cuff volume and the number of intubation attempts. Throat clearing was associated significantly with the increase in cuff mean pressure. Only the increase in habitual pitch was associated significantly with the increase in cuff volume. The acute short-term effect of endotracheal intubation on voice is significant. The most important endotracheal tube parameters that affect the vocal changes are the cuff mean pressure and volume. The laryngeal contribution to these vocal changes seems to be minimal All vocal symptoms increased significantly except for globus pharyngeus at 2 hours postoperatively. The acoustic parameters did not change significantly except for a decrease in MPT. At 24 hours postoperatively, all vocal symptoms subsided with no significant difference to baseline value. The habitual pitch increased significantly, and the rest of the parameters remained comparable to baseline value.

The KayPENTAX Visi-Pitch, Model 3300, was used to perform the acoustic analysis in this study.

“Effect of Deep Brain Stimulation on Different Speech Subsystems in Patients with Multiple Sclerosis,” Putzer, Manfred, William John Barry, and Jean Richard Moringlane, Journal of Voice, Vol. 21 No. 6, pp. 741-753, November 2007.

Summary: The effect of deep brain stimulation on articulation and phonation subsystems in seven patients with multiple sclerosis (MS) was examined. Production parameters in fast syllable repetitions were defined and measured, and the phonation quality during vowel productions was analyzed. Speech material was recorded for patients (with and without stimulation) and for a group of healthy control speakers. With stimulation, the precision of glottal and supraglottal articulatory gestures is reduced, whereas phonation has a greater tendency to be hyperfunctional in comparison with the healthy control data. Different effects on the two speech subsystems are induced by electrical stimulation of the thalamus in patients with MS.

In this study, the KayPENTAX CSL, Model 4300B, was used to capture and digitize the EGG and microphone signals that were recorded simultaneously.

“Acoustic Voice Analysis of Prelingually Deaf Adults Before and After Cochlear Implantation,” Evans, Maegan K., and Dimitar D. Deliyski, Journal of Voice, Vol. 21 No. 6, pp. 669-682, November 2007.

Summary: It is widely accepted that many severe to profoundly deaf adults have benefited from cochlear implants (CIs). However, limited research has been conducted to investigate changes in voice and speech of prelingually deaf adults who receive CIs, a population well known for presenting with a variety of voice and speech abnormalities. The purpose of this study was to use acoustic analysis to explore changes in voice and speech for three prelingually deaf males pre- and post implantation over 6 months. The following measurements, some measured in varying contexts, were obtained: fundamental frequency (F0), jitter, shimmer, voice-to-harmonic ratio, voice turbulence index, soft phonation index, amplitude- and F0 variation, F0-range, speech rate, nasalance, and vowel production. Characteristics of vowel production were measured by determining the first formant (F1) and second formant (F2) of vowels in various contexts, magnitude of F2-variation, and rate of F2-variation. Perceptual measurements of pitch, pitch variability, loudness variability, speech rate, and intonation were obtained for comparison. Results are reported using descriptive statistics. The results showed patterns of change for some of the parameters while there was considerable variation across the subjects. All participants demonstrated a decrease in Fo in at least one context and demonstrated a change in nasalance toward the norm as compared to their normal hearing control. The two participants who were oral language communicators were judged to produce vowels with an average of 97.2% accuracy and the sign-language user demonstrated low percent accuracy for vowel production.

The KayPENTAX Computerized Speech Lab (CSL), Model 4400, and Nasometer II, Model 6400, were used to obtain the objective data in this study. In addition to the core CSL program, other CSL applications that were used included the Motor Speech Profile (MSP), Model 5141, and Multi-Dimensional Voice Program (MDVP), Model 5105.

“Predictors of Laryngeal Complications in Patients Implanted with the Cyberonics Vagal Nerve Stimulator,” Shaw, Gary Y., Philip Sechtem, Jeff Searl, and Emily S. Dowdy, Annals of Otology Rhinology & Laryngology, Vol. 115 (4), pp. 260-267, April 2006.

Objectives: Since its approval by the US Food and Drug Administration in 1997 for management of medically refractory seizures, more than 35,000 patients have been implanted with the Cyberonics vagal nerve stimulator. Preliminary reports described transient vocal changes in the majority of subjects, which were thought to be short-term. However, these reports were for the most part based upon perceptual evaluations by the subjects themselves. Later reports described possibly more permanent recurrent laryngeal nerve injury and recommended measuring the nerve diameter to use the safest spiral cuff electrode. To date, no study has systematically evaluated vocal fold mobility in subjects before and after implantation. The objectives of this study were to determine the true incidence of both sort- and long-term recurrent laryngeal nerve injuries and determine whether there are any potential indicators to predict in which patients long-term nerve deficits may develop.

Methods: Thirteen subjects underwent preimplantation laryngeal electromyography, videolaryngoscopy, measurement of the maximum phonation time. Voce Handicap Index determination, and Consensus Auditory-Perceptual Evaluation of Voice. Two weeks after implantation, all subjects underwent videolaryngoscopy. Three months after implantation and activation of the device, all subjects were evaluated.

Results: Six of the 13 subjects had significant vocal fold mobility abnormalities at 2 weeks. Significant electromyographic abnormalities were detected before implantation in 5 subjects. All 5 of the subjects, at 3 months after implantation, had prolonged left vocal fold paresis.

Conclusions: The authors conclude that perioperative vocal fold paresis occurs in approximately 50% of subjects. Further, laryngeal electromyography performed before implantation of the vagal nerve stimulator is a statistically significant predictor (p < .05) of which patients may be at risk for extended vocal fold abnormalities. Possible explanations for this phenomenon are offered. Surgical modifications to limit vagal nerve injury are offered.

In this study, videolaryngoscopy was performed with a KayPENTAX RLS, Model 9100, using a 70-degree rigid endoscope. Acoustic analysis was performed using the KayPENTAX CSL, Model 4300B. Additionally, all patients underwent flexible laryngoscopic examination using the KayPENTAX fiberoptic flexible endoscope, Model FNL-10RP3.

“Treatment of Adductor-Type Spasmodic Dysphonia by Surgical Myectomy: A Preliminary Report,” Koufman, Jamie A., Catherine J. Rees, Stacey L. Halum, and David Blalock, Annals of Otology, Rhinology & Laryngology, Vol. 115 (2), pp. 97-102, February 2006. 

Objectives: Despite the belief that it represents a central neurologic dysfunctional process, adductor-type spasmodic dysphonia without tremor is usually effectively treated by injection of botulinum toxin A; however, in most cases such injections must be repeated every few months. A promising new surgical procedure is herein reported.

Methods: Under local anesthesia with intravenous sedation, a large laryngoplasty window is created, and under direct vision with intraoperative voice monitoring, fibers from the thyroarytenoid and lateral cricoarytenoid muscles are removed until breathiness occurs. The two sides are staged; that is, one side is done at a time, with surgery on the second side being performed 3 to 6 months after that on the first side, if needed.

Results: This was a retrospective, unblended study of 5 patients who underwent myectomy of the thyroarytenoid and lateral cricoarytenoid muscles. The preliminary results show improved voice fluency in all patients at 5 to 19 months of follow-up. There was no period of prolonged breathiness or dysphagia in any of the patients, and there were no surgical complications.

Conclusions: Myectomy of the thyroarytenoid and lateral cricoarytenoid muscles is a promising new surgical treatment for adductor-type spasmodic dysphonia that may effectively mimic “permanent” botulinum toxin injections.

Acoustic analysis in this study was performed using the KayPENTAX Computerized Speech Lab (CSL) in conjunction with the CSL Pitch Program, Model 4331.

“The Effects of Fundamental Frequency Level on Voice Onset Time in Normal Adult Male Speakers,” McCrea, Christopher R. and Richard J. Morris, Journal of Speech, Language, and Hearing Research, Vol. 48 No. 5, pp. 1013-1024, October 2005.

The purpose of this study was to examine the effect of fundamental frequency (Fo) on stop consonant voice onset time (VOT). VOT was measures from the recordings of 56 young men reading phrases containing all 6 English voiced and voiceless stops in word-initial position across high-, medium-, and low-Fo levels. Separate analyses of variance for the voice and voiceless stops revealed no significant main effect for Fo for the voiced stops but a significant Fo effect for the voiceless stops. Across the voiceless stops, productions at high Fos displayed significantly shorter VOTs than productions at low or mid Fos. The findings indicated that researchers must take into account the Fo level at which voiceless stop VOT is measured.

Voice recordings, in this study, were digitized and acoustically analyzed using a KayPENTAX Computerized Speech Lab (CSL), Model 4300B.

“Coordination of Oral and Laryngeal Movements in the Perceptually Fluent Speech of Adults Who Stutter,” Max, Ludo and Vincent L. Gracco, Journal of Speech, Language, and Hearing Research, Vol. 48 No. 3, pp. 524-542, June 2005.

This work investigated whether stuttering and nonstuttering adults differ in the coordination of oral and laryngeal movements during the production of perceptually fluent speech. This question was addressed by completing correlation analyses that extended previous acoustic studies by others as well as inferential analyses based on the within-subject central tendency and variability of acoustic and physiological indices of oral-laryngeal control and coordination. Stuttering and nonstuttering adults produced the target /p/ as the medial consonant in C1V1#C2V2C3 sequences (C = consonant; V = vowel or diphthong, # = word boundary) embedded in utterances differing in length and location of the target movements. No between-groups differences were found for across- or within- subject correlations between acoustic measures of stop gap and voice onset time (VOT). However, the acoustic data did show longer duration for devoicing interval and VOT in the stuttering versus nonstuttering individuals, in the absence of a difference for a proportional measure specifically reflecting oral-laryngeal relative timing. Analyses of combined kinematic and electroglottographic data revealed that the stuttering individuals’ speech was also characterized by (a) longer durations from bilabial closing movement onset and peak velocity to V1 vocal fold vibration offset and (b) greater within-subject variability for dependent variables that were physiological indices of devoicing interval and VOT, but again no between-groups differences were found for specific indices of oral-laryngeal relative timing. Overall, findings suggest that, for the production of voiceless bilabial stops in perceptually fluent speech, stuttering and nonstuttering adults differ in the duration of intervals defined by events within as well as across the oral and laryngeal subsystems, but the groups show similar patterns of relative timing for the involved oral and laryngeal movements.

In this study, the KayPENTAX Multi-Speech, Model 3700, was used to obtain and analyze acoustic measures.

“Quantifying the Effect of Compression Hearing Aid Release Time on Speech Acoustics and Intelligibility,” Jenstead, Lorienne M. and Pamela E. Souza, Journal of Speech, Language, and Hearing Research, Vol. 48 No. 3, pp. 651-667, June 2005.

Compression hearing aids have the inherent, and often adjustable, feature of release time from compression. Research to date does not provide a consensus on how to choose or set release time. The current study had 2 purposes: (a) a comprehensive evaluation of the acoustic effects of release time for a single-channel compression system in quiet and (b) an evaluation of the relation between the acoustic changes and speech recognition. The release times under study were 12, 100, and 800 ms. All of the stimuli were VC syllables from the Nonsense Syllable Task spoken by a female talker. The stimuli were processed through a hearing aid simulator at 3 input levels. Two acoustic measures were made on individual syllables: the envelope-difference index and CV ratio. These measurements allowed for quantification of the short-term amplitude characteristics of the speech signal and the changes to these amplitude characteristics caused by compression. The acoustic analyses revealed statistically significant effects among the 3 release times. The size of the effect was dependent on the characteristics of the phoneme. Twelve listeners with moderate sensorineural hearing loss were tested for their speech recognition for the same stimuli. Although release time for this single-channel, 3:1 compression ratio system did not directly predict overall intelligibility for these nonsense syllables in quiet, the acoustic measurements reflecting the changes due to release time were significant predictors of phoneme recognition. Increased temporal-envelope distortion was predictive of reduced recognition for some individual phonemes, which is consistent with previous research on the importance of relative amplitude as a cue to syllable recognition for some phonemes.

The KayPENTAX Multi-Speech, Model 3700, was used to perform the acoustic analysis  in this study, specifically to obtain the CV ratio (i.e., the difference in decibels between adjacent consonants and vowels).

“Voice-over: Perceptual and Acoustic Analysis of Vocal Features,” Medrado, Reny, Leslie Piccolotto Ferreira, and Mara Behlau, Journal of Voice, Vol. 19 No. 3, pp. 340-349, September 2005.

Voice-overs are professional voice users who use their voices to market products in the electronic media. The purposes of this study were to (1) analyze voice-overed and non-overed productions of an advertising text in two groups consisting of 10 male professional voice-overs and 10 male non-voice-overs; and (2) determine specific acoustic features of voice-over productions in both groups. A naïve group of listeners were engaged for the perceptual analysis of the recorded advertising text. The voice-overed production samples from both groups were submitted for analysis of acoustic and temporal features. The following parameters were analyzed: (1) the total text length, (2) the length of the three emphatic pauses, (3) values of the mean, (4) minimum, (5) maximum fundamental frequency, and (6) the semitone range. The majority of voice-overs and non-voice-overs were correctly identified by the listeners in both productions. However voice-overs were more consistently correctly identified than non-voice-overs. The total text length was greater for voice-overs. The pause time distribution was statistically more homogeneous for the voice-overs. The acoustic analysis indicated that the voice-overs had lower values of mean, minimum, and maximum fundamental frequency and a greater range of semitones. The voice-overs carry the voice-overed features to their non-voice-overed production.

In this study, the Real-Time Pitch module of the KayPENTAX Visi-Pitch II was used to analyze both temporal and acoustic parameters.

“The Impact of Specific Exertion on the Efficiency and Ease of the Voice,” Bagnall, Alison D and Kirsty McCulloch, Journal of Voice, Vol. 19 No. 3, pp. 384-390, September 2005.

Even though most singers and other professional voice users are encouraged to relax to optimize the quality and performance of the voice, observations of acclaimed singers, actors, and public speakers would suggest otherwise. These successful vocal performers appear to be energized, actively working and exerting themselves. For this reason, a study was designed to explore the role of exertion in maintaining and optimizing the voice. The focus of this study was the possibility that increasing exertion could improve the voice and might result in the voice user experiencing less strain and, therefore, more comfort and ease. Ten subjects were recorded before and after completing a workshop to develop their skills with precise use of effort involving selected parameters of the larynx and vocal tract. Self-reported ratings of degree of exertion and level of comfort were collected at the time of each recording. The preworkshop and postworkshop recordings were analyzed acoustically and perceptually to compare the degree of noise in the signal that corresponds with the efficiency of the voice. The results indicated that, for all subjects, the quality of the voice improved with an increase in the use of specific exertion. Furthermore, ease and comfort also significantly increased. 

The KayPENTAX Computerized Speech Lab (CSL) was used in conjunction with the KayPENTAX  Multi-Dimensional Voice Program (MDVP) to perform the acoustic analysis in this study.

“Spectral Amplitude Measures of Adductor Spasmodic Dysphonic Speech,” Cannito, Michael P., Eugene H. Buder, and Lesya B. Chorna, Journal of Voice, Vol. 19 No. 3, pp. 391-410, September 2005.

 Spectral amplitude measures are sensitive to varying degrees of vocal fold adduction in normal speakers. This study examined the applicability of harmonic amplitude differences to adductor spasmodic dysphonia (ADSD) in comparison with normal controls. Amplitudes of the first and second harmonics (H1, H2) and of harmonics affiliated with the first and second harmonics (A1, A2, A3) were obtained from spectra of vowels /a/ and /i/ excerpted from connected speech. Results indicated that these measures could be made reliably in ADSD. With the exception of H1*-H2*, harmonic amplitude difference (H1*-A1, H1*-A2, and H1*-A3) exhibited significant negative linear relationships (P < 0.05) with clinical judgments of overall severity. The four harmonic amplitude differences significantly differentiated between pre-BT and post-BT productions (P < 0.05). After treatment, measurements from /a/ detected significant differences between ADSD and normal controls (P < 0.05), but measurements from /i/ did not. LTAS analysis of ADSD patients’ speech samples proved a good fit with harmonic amplitude difference measures. Harmonic amplitude differences also significantly correlated with perceptual judgments of breathiness and roughness (P < 0.05). These findings demonstrate high clinical applicability for harmonic amplitude differences for characterizing phonation in the speech of persons with ADSD, as well as normal speakers, and they suggest promise for future application to other voice pathologies.

In this study, the KayPENTAX CSL, Model 4300B, was used to digitize and analyze subjects’  speech samples.

This study was designed to examine the temporal acoustic differences between male trained singers and nonsingers during speaking and singing across voiced and voiceless English sop consonants. Recordings were made of 5 trained singers and 5 nonsingers, and acoustically analyzed for voice onset time (VOT). A mixed analysis of variance showed that the male trained singers had significantly longer mean VOT than did the nonsingers during voiceless stop production. Sung productions of voiceless stops had significantly longer mean VOTs than did the spoken productions. No significant differences were observed for the voiced stops, nor were any interactions observed. These results indicated that vocal training and phonatory task have a significant influence on VOT.

The KayPENTAX CSL, Model 4300B, was used to perform the acoustic analysis in this study.

“Pitch Discrimination and Pitch Matching Abilities of Adults Who Sing Inaccurately,” Bradshaw, Elizabeth and Monica A. McHenry, Journal of Voice, Vol. 19 No. 3, pp. 431-439, September 2005.

Past research regarding singing ability has provided evidence that both supports and refutes a relationship between pitch discrimination ability and pitch production ability. Researchers have suggested that these skills improve with age. Despite this suggestion, most investigators studying singing ability have included only children as participants. Additionally, although many researchers have studied accurate singers, few have directly studied persons who do not sing accurately. We designed this study to examine the relationship between pitch discrimination ability and pitch production ability in inaccurate adult singers. Fifteen adults, aged 18 to 40 years that met specific criteria qualified as inaccurate singers. Each participated in two tasks, a pitch discrimination task and a pitch production task. We used the Multi-Dimensional Voice Profile-Advanced (Kay Elemetrics Corporation, Lincoln Park, NJ) to determine the frequency of each participant’s vocal productions during the pitch production task. We also used a Pearson product moment correlation to analyze the relationship between pitch discrimination and pitch production accuracy within a semitone of the target frequency. No meaningful relationship was found, and results were not statistically significant. However, the inaccurate singers in this study could be classified into two separate categories, those who discriminated pitches accurately, but produced pitches inaccurately, and those who discriminated pitches inaccurately and produced pitches inaccurately. These findings may be of great importance to music educators and impact the focus of instruction when teaching an inaccurate singer to sing more accurately.

In this study, the KayPENTAX CSL was used in conjunction with the KayPENTAX Multi-Dimensional Voice Profile for acoustic analysis.

“Vocal Projection in Actors: The Long Term Average Spectral Features That Distinguish Comfortable Acting Voice From Voicing with Maximal Projection in Male Actors,” Pinczower, Rachel and Jennifer Oates, Journal of Voice, Vol. 19 No. 3, pp. 440-453, September 2005.

This study explored whether acoustic and perceptual features could distinguish comfortable from maximally projected acting voice. Thirteen professional male actors performed a passage from William Shakespeare’s Julius Caesar twice. The first delivery used their comfortably projected voices, whereas the second used maximal projection. Acoustic measures, expert rating, and self-ratings of projection and voice quality were investigated. Long-term average spectra (LTAS) and sound pressure level (SPL) analyses were conducted. Perceptual variables included projection, breathiness, roughness, and strain. When comparing the intensity difference between the higher (2-44 kHz) and lower (0-2 kHz) regions of the spectrum in voice samples from the maximal projected condition, LTAS analyses demonstrated increased acoustic energy in the higher part of the spectrum. This LTAS pattern was not as evident in the comfortable projected condition. These findings offered some preliminary support for the existence of an actor’s formant (prominent peak in the upper art of the spectrum) during maximal projection.

Researchers in this study used the KayPENTAX Multi-Speech, Model 3700, to determine mean and peak SPL.

“Acoustic Analysis of the Voice in Pediatric Cochlear Implant Recipients: A Longitudinal Study,” Campisi, P., A. Low, B. Papsin, R. Mount, R. Cohen-Kerem, and R. Harrison, Laryngoscope, Vol. 115, pp. 1046-1050, June 2005.

Objectives: To characterize inherent acoustic abnormalities of the deaf pediatric voice and the effect of artificially restoring auditory feedback with cochlear implantation.

Design: Inception cohort.

Settings: Academic referral center.

Patients: Twenty-one children with severe to profound hearing loss (15 prelingually deaf, 6 postlingually deaf) accepted into the cochlear implant program were followed for up to 6 months. Patients unable to perform the vocal exercises were excluded.

Interventions: Objective voice analysis was performed using the Computerized Speech Laboratory (Kay Elemetrics) prior to cochlear implantation, at the time of implant activation and at 2 and 6 months postactivation. Assessments were based on sustained phonations and dynamic ranges.

Main Outcome Measure: Fundamental frequency, long-term control of fundamental frequency (vF0) and long-term control of amplitude (vAM) were derived from sustained phonations. The dynamic frequency from sustained phonations. The dynamic frequency range was derived from scale exercises. Formant frequencies (F1, F2, F3) were determined using linear predictive coding.

Results: Fundamental frequency was not altered by implant activation or experience (P = 0.342). With profoundly deaf subject, the most prevalent acoustic abnormality was a poor long-term control of frequency (vF0, 2.81%) and long-term control of amplitude (vAM, 23.58%). Implant activation and experience had no effect on the long-term control of frequency (P = 0.106) but normalized the long-term control of amplitude (P = 0.007). The mean frequency range increased from 311.9 Hz preimplantation to 483.5 Hz postimplantation (P = 0.08). The F1/F2 ratio remained stable (P = 0.476).

Conclusion: In children, severe to profound deafness results in poor long-term control of frequency and amplitude. Cochlear implantation restores control of amplitude only and implies the need for additional rehabilitative strategies for restoration of control of frequency.

Researchers in this study used the KayPENTAX CSL, Model 4400, for data collection and analysis, in conjunction with KayPENTAX’s Multi-Dimensional Voice Program, Model 5105, and Real-Time Pitch, Model 5121.

“Influence of Data Acquisition Environment on Accuracy of Acoustic Voice Quality Measurements,” Deliyski, Dimitar D., Maegan K. Evans, and Heather S. Shaw, Journal of Voice, Vol. 19 No. 2, pp. 176-186, June 2005.

Accuracy of acoustic voice analysis is influenced by the quality of recording. Lately, articles have suggested that soundcards perform equivalently to specialized professional-grade data acquisition (DA) systems. The purpose of this study was to investigate the influence of DA environment (DA system and microphone) on acoustic voice quality measurement (VQM) while balancing for gender, age, intersubject and intrasubject variability, and analysis software. More specifically, the relative performance of different hardware environments and the relationship between their technical characteristics and VQM performance was investigated. The discretization error and the effective dynamic range of the different DA environments were measured. We used 3 software systems to record and measure separately 2000 acoustic samples of sustained phonation for fundamental frequency, jitter, and shimmer. Analyses of variance (ANOVA) were performed with these parameters as the dependent variables. The results of the study suggested that professional-grade DA hardware is strongly recommended to provide accurate and valid voice assessment. The fundamental frequency measurement differences across DA environments were highly correlated to the discretization error (r = 1.00), whereas jitter and shimmer were highly correlated to the effective dynamic range of the DA environments (r = -0.68 and r = 0.86, respectively).

The KayPENTAX Computerized Speech Lab (CSL), Model 4400, was one of the professional-grade data acquisition (DA) systems used by researchers in this study to determine the effect of DA environment (DA system and microphone) on acoustic voice quality measurement (VQM).

The purpose of this study was to investigate if there was an effect of duration of speaking on determination of habitual pitch. Five speaking periods commonly used to elicit habitual pitch in clinical voice evaluations were compared (1, 5, 15, 30, and 60 seconds). Thirty female speakers with normal voices participated. Results of a within-subject univariate F-test revealed a statistically significant (p < 0.001) difference in habitual pitch among the speaking periods. Habitual pitch for the 1-second and 60-second speaking periods were found to be statistically significantly (p < 0.05) different than all remaining speaking periods, and the habitual pitch for the 30-second speaking period was found to be statistically significantly (p < 0.05) different than 60-second speaking period. Implications for the use of various speaking durations when determining habitual pitch are discussed, as is the possibility of a speaking duration effect on determination of other pitch-related voice parameters.

KayPENTAX’s Visi-Pitch II, Model 3300, was used to determine the speaking fundamental frequency (SFF) of the participants in this study.

“Spectral Moments of the Long-term Average Spectrum: Sensitive Indices of Voice Change After Therapy?,” Tanner, Kristine, Nelson Roy, Andrea Ash, and Eugene H. Buder, Journal of Voice, Vol. 19 No. 2, pp. 211-222, June 2005.

Voice clinicians require an objective, reliable, and relatively automatic method to assess voice change after medical, surgical, or behavioral intervention. This measure must be sensitive to a variety of voice qualities and severities, and preferably should reflect voice in continuous speech. The long-term average spectrum (LTAS) is a fast Fourier transform-generated power spectrum whose properties can be compared with a Gaussian bell curve using spectral moments analysis. Four spectral moments describe features of the LTAS: Spectral mean (Moment 1) and standard deviation (Moment 2) represent the spectrum’s central tendency and dispersion, respectively. Skewness (based on Moment 3) and kurtosis (based on Moment 4) represent the spectrum’s tilt and peakedness, respectively. To examine whether the first four spectral moments of the LTAS were sensitive to perceived voice improvement after voice therapy, this investigation compared pretreatment and posttreatment voice samples of 93 patients with functional dysphonia using spectral moments analysis. Inspection of the results revealed that spectral mean and standard deviation lowered significantly with perceived voice improvement after successful behavioral management (p < 0.001). However, changes in skewness and kurtosis were not significant. Furthermore, lowering of the spectral mean uniquely accounted for approximately 14% of the variance in the pretreatment to posttreatment changes observed in perceptual ratings of voice severity (p < 0.001), indicating that spectral mean (ie, Moment 1) of the LTAS may be one acoustic marker sensitive to improvement in dysphonia severity.

KayPENTAX’s Computerized Speech Lab (CSL), Model 4300B, was used to digitize the speech samples in this study; spectral moments were generated from the LTAS of each voice sample using the KayPENTAX Multi-Speech, Model 3700.

“Evaluating the Influence of Warmup on Singing Voice Quality Using Acoustic Measures,” Amir, Ofer, Noam Amir, and Orit Michaeli, Journal of Voice, Vol. 19 No. 2, pp. 252-260, June 2005.

Vocal warmup is generally accepted as vital for singing performance. However, only a limited number of studies have evaluated this effect quantitatively. In this study, we evaluated the effect of vocal warmup on voice production, among young female singers, using a set of acoustic parameters. Warmup reduced frequency-perturbation (p < 0.001) and amplitude-perturbation values (p < 0.05). In addition, warmup increased singer’s formant amplitude (p < 0.05) and improved noise-to-harmonic ratio (p < 0.05). Tone-matching accuracy, however, was not affected by warmup. The effect of vocal warmup on frequency-perturbation parameters was more evident among mezzo-soprano singers than it was among soprano singers. It was also more evident in the low pitch-range than in the higher pitch-ranges (p < 0.05). The results of this study provide valid support for the advantageous effect of vocal warmup on voice quality and present acoustic analysis as a valuable and sensitive tool for quantifying this effect.

In this study, acoustic analysis was performed using the KayPENTAX Multi-Dimensional Voice Program (MDVP), Model 5105.

“Acoustic Prediction of Voice Type in Women with Functional Dysphonia,” Awan, Shahenn N. and Nelson Roy, Journal of Voice, Vol. 19 No. 2, pp. 268-282, June 2005.

The categorization of voice into quality type (ie, normal, breathy, hoarse, rough) is often a traditional part of the voice diagnostic. The goal of this study was to assess the contributions of various time and spectral-based acoustic measures to the categorization of voice type for a diverse sample of voices collected from both functionally dysphonic (breathy, hoarse, and rough) (n = 83) and normal women (n = 51). Before acoustic analyses, 12 judges rated al voice samples for voice quality type. Discriminant analysis, used the modal rating of voice type as the dependent variable, produced a r-variable model (comprising time and spectral-based measures) that correctly classified voice type with 79.9% accuracy (74.6% classification accuracy on cross-validation). Voice type classification was achieved based on two significant discriminant functions, interpreted as reflecting measures related to “Phonatory Instability” and “F0 Characteristics.” A cepstrum-based measure (CPP/EXP ratio) consistently emerged as a significant factor in predicting voice type; however, variables such as shimmer (RMS dB) and a measure of low- vs. high-frequency spectral energy (the Discrete Fourier Transformation ratio) also added substantially to the accurate profiling and prediction of voice type. The results are interpreted and discussed with respect to the key acoustic characteristics that contributed to the identification of specific voice types, and the value of identifying a subset of time and spectral-based acoustic measures that appear sensitive to a perceptually diverse set of dysphonic voices.

Voice samples in this study were recorded and digitized using the KayPENTAX Computerized Speech Lab (CSL), Model 4300B.

“The Effect of Hemodialysis on Voice: An Acoustic Analysis,” Hamdan, Abdul-Latif, Walid Medawar, Abbas Younes, Hala Bikhazi, and Nabil Fuleihan, Journal of Voice, Vol. 19 No. 2, pp. 290-295, June 2005.

Because respiration is part of the well-coordinated process necessary for phonation, this study was conducted with the purpose of analyzing the effect of chronic hemodialysis on voice characteristics of patients with chronic renal failure. A total of 57 patients were recruited for the study, including 31 males and 26 females ranging in age from 16 to 85 years. Patients underwent evaluation of their voice directly before and after hemodialysis using the Kay Elemetrics Visi-Pitch (Model 3300; Kay Elemetrics Corporation, Lincoln Park, New Jersey). The vocal acoustic parameters studied include habitual pitch, pitch range, relative average perturbation, shimmer, noise-to-harmonic ratio, voice turbulence index, maximum phonation time, and voice energy. The data were analyzed using the paired t-test for the total sample and the nonparametric test for the female and male subgroups. The total sample analysis showed a statistically significant increase in the habitual pitch after the hemodialysis (p < 0.05), with a borderline increase in the pitch range and maximum phonation time (p < 0.10). In the female group, there was a statistically significant increase in the habitual pitch and a borderline increase in the relative average perturbation. In the male group, there was a significant increase in the habitual pitch with a borderline increase in maximum phonation time. Discussion of the after-mentioned results in presented.

In this study, the VQA (Vocal Quality Assessment) and the PE (Pitch and Energy) modules of the KayPENTAX Visi-Pitch, Model 3300, were used to analyze a variety of acoustic parameters including habitual pitch, maximum phonation time, pitch range, voice energy, relative average perturbation, shimmer, NHR, and voice turbulence index.

“A Comparative Study of Acoustic Voice Measurements by Means of Dr. Speech and Computerized Speech Lab,” Smits, Ilse, Piet Ceuppens, and Marc S. De Bodt, Journal of Voice, Vol. 19 No. 2, pp. 187-196, June 2005.

In this study, the calculations and results of acoustic voice analysis as calculated by two different analysis systems (Doctor Speech (DRS), Tiger Electronics, Neu-Anspach, German, and Computerized Speech Lab (CSL), Kay Elemetrics Corporation, Lincoln Park, NJ) are compared. A group of 120 normal voices was selected for analysis of the objective parameters: fundamental frequency (F0), variation of F0 (F0SD), jitter, shimmer, and harmonics-to-noise ratio (HNR). The subject group was a random selection of normal voices of adults. The aim of this comparison was to find determined differences and similarities in data measurements between both systems to make data transfer possible. A significant correlation was found for F0, HNR, and shimmer relative. The correlation for jitter (relative and absolute) and F0SD was weak. DRS and CSL are not comparable in absolute figures, but their judgment against normative data is identical Further research is necessary to explore the affect on pathological voices or child voices.

The KayPENTAX CSL, Model 4300B, in conjunction with KayPENTAX’s Multi-Dimensional Voice Program (MDVP), was used for acoustic voice analysis in this study.

“Influence of Aging and Sex on Voice Parameters in Patients with Unilateral Vocal Cord Paralysis,” Kandogan, Tolga, and Eberhart Seifert, Laryngoscope, Vol. 115, pp. 655-660, April 2005.

Objectives: The objective of this study was to investigate influences of aging and sex on different voice parameters in patients with unilateral vocal cord paralysis (VCP).

Study Design: Retrospective review of patients with unilaterial VCP.

Material and Methods: Forty-seven patients, 22 males, 25 females (24-85 years), were enrolled in the study. The diagnosis of VCP was established by videolaryngostroboscopy. The acoustic parameters of jitter, shimmer, degree of subharmonic, noise to harmonic ratio, fundamental frequency, and maximal intensity were measured. The auditive voice analysis included roughness, breathiness, and hoarseness. Statistical analysis involves Pearson’s bivariate correlation coefficients and two-way analysis of variance with interaction variables. 

Resolution: After unilateral VCP in the elderly, some sex- and age-related differences in the restriction of the voice can be documented.

Conclusion: In general, the investigated voice parameters showed similar tendencies to those in otherwise healthy aging persons.

Researchers in this study used the KayPENTAX Multi-Dimensional Voice Program (MDVP) to analyze jitter, shimmer, and NHR.

“Effects of genioglossal muscle advancement on speech,” Vähätalo, Kimmo, Juha-Pertti Laaksonen, Henna Tamminen, Olli Aaltonen, and Risto-Pekka Happonen, Otolaryngology, Vol. 132 No. 4, pp. 636-640, April 2005.

Objective: The effects of the genioglossal muscle advancement on phonetic quality of speech were studied analyzing the acoustic features of vowel sounds.

Study Design and Setting: The study group consisted of 5 men suffering from partial upper airway obstruction during sleep. To prevent tongue base collapse, genioglossal muscle advancement was made with chin osteotomy without hyoid myotomy and suspension. The speech material consisted of 8 vowels produced in sentence context repeated 10 times before the operation, and 10 days and 6 weeks after the operation. The acoustic features of vowels were analyzed.

Results: The operation had no significant effects on vowel quality. Only for 2 of the subjects the pitches changed systematically due to the operation.

Conclusion: According to the acoustic analysis, genioglossal muscle advancement with chin osteotomy has no effects on vowel production. Some short-term changes were observed, but these changes were highly individual.

Significance: The operation seems to have no potential to change vowel production. 

In this study, the acoustic analysis of speech samples was performed using the KayPENTAX Computerized Speech Lab (CSL), Model 4300B.

“Adverse Effects of Environmental Noise on Acoustic Voice Quality Measurements,” Deliyski, Dimitar D., Heather S. Shaw, and Maegan K. Evans, Journal of Voice, Vol. 19 No. 1, pp. 15-28, March 2005. 

An accurate analysis of voice quality is imperative when using acoustic measurements to diagnose vocal pathologies. It is known that noise has a significant effect on the reliability and validity of acoustic voice measurements, but the precise relationship has not been established. The purpose of this study was to investigate the influence of noise on the accuracy, reliability, and validity of acoustic voice quality measurements while balancing for gender, age, intersubject and intrasubject variability, microphones, computer hardware, analysis software, and type of noise. Level of noise was precisely controlled. The specific focus of interest was to determine the critical levels of noise that can invalidate voice quality measurements and to generate practical recommendations. Results suggest that the recommended, acceptable, and unacceptable levels of noise in the acoustic environment are above 42 dB, above 30 dB, and below 30 dB signal-to-noise ratio, respectively.

The KayPENTAX Computerized Speech Lab (CSL), Model 4400, was used in conjunction with the Multi-Dimensional Voice Program (MDVP), Model 5105, for voice analysis in this study.

 
“Vocal Range and Intensity in Actors: A Studio Versus Stage Comparison,” Emerich, Kate A., Ingo R Titze, Jan G. Švec, Peter S. Popolo, and Gary Logan, Journal of Voice, Vol. 19 No. 1, pp. 78-83, March 2005.

A voice range profile (VRP) was obtained from each of eight professional actors and compared with two speech range profiles (SRPs). One speech profile was obtained during the dramatic reading of a scene in the laboratory and the other during a performance onstage in a professional theater. The objective was to determine the pitch and loudness ranges used by the actors in speech relative to the VRP. The principal question of interest was whether the actors stayed within the center of the VRP, or whether they tended to drift toward the boundaries of intensity and frequency. A second question was whether the performance within the laboratory accurately reflects that of a stage performance. The results suggest that some subjects tend to exceed the center of the VRP during the stage performance. It is hypothesized that these actors may stress their vocal mechanism during performance and are more likely candidates for vocal injury. 

The KayPENTAX Computerized Speech Lab (CSL), Model 4400, and Voice Range Profile (VRP) Program, Model 4326, were used to obtain the voice range profile of each subject in this study.

“The Efficacy of Resonance Method to Hyperfunctional Dysphonia from Physiological, Acoustic and Aerodynamic Aspects: The Preliminary Study,” Chen, Sheng Hwa, Jui-Lin Huang, and Wei-Shan Chang, Asia Pacific Journal of Speech, Language and Hearing, Vol. 8, No. 3, pp. 200-203, 2003.

Abstract: The purpose of this study is to investigate the treatment efficacy of Resonance Voice Therapy (RVT) to hyperfunctional dysphonic patients from physiological, acoustic and aerodynamic aspects. Twenty-one females, age range 23 to 56 years, diagnosed with hyperfunctional dysphonia in the Veterans General Hospital, Taipei were equally divided into seven groups. The therapy was provided by a speech pathologist once a week, for 90 minutes per session, for eight weeks. Laboratory tests of videostroboscopy, auditory perceptual judgment, acoustic analysis and aerodynamic analysis were done on all subjects before and after RVT. A paired t-test was used to analyze test-retest reliability and significance of therapy. After RVT, there is significant improvement of vocal fold closure, vocal fold vibration and voice quality. A significant decrease of shimmer and intra-oral pressure, and a significant increase in speaking frequency range, physiological frequency range and intensity range quantify subjective improvements. RVT reflects physiological changes in respiratory, laryngeal and resonant systems. This therapy technique proves to be an effective treatment method for hyperfunctional voice-disordered patients.

In this study, Kay’s RLS Model 9100 light source was used to perform videostroboscopic examinations; Kay’s VRP, Model 4326 was used to obtain maximum vocal performance data; and Kay’s Computerized Speech Lab (CSL), Model 4300B, was used for acoustic analysis.

“Identification of Cantonese Tones by Children with Sensory Hearing Impairment: Effects of Noise and Hearing Aid Frequency Response,” Morris, David and Joseph Kei, Asia Pacific Journal of Speech, Language and Hearing, Vol. 8, No. 3, pp. 212-220, 2003.

Abstract: The present study examined the tonal identification abilities of a control group (n = 23 normal hearing children, mean age = 13.6 years; SD = 1.9) and two experimental groups: a mild to moderate hearing-impaired group (n = 11, mean age = 15.8 years, SD = 1.9); and, a moderately severe hearing-impaired group (n = 11, mean age = 14.3 years, SD = 3.7). The two experimental groups were tested monaurally in a sound field under two different hearing aid frequency responses and two noise conditions (quiet/noise). All participants in the experimental group were of normal intelligence and free from other disabilities except hearing impairment. The results revealed that tonal identification ability was impeded as the degree of hearing impairment increased. A noise effect was found, showing a significant lower tone identification score in noise than in quiet. The hearing aid frequency response effect, however, did not reach significance. The most common tonal identification errors, made by the hearing-impaired groups, were tone 6/tone 4 and tone 5/tone 2 confusions, with their reciprocals. These results highlight the difficulty of hearing-impaired children in identifying Cantonese tones, particularly in noisy environments.

Acoustical analysis of the subjects’ six word tokens was performed using Kay’s DSP Sona-Graph, Model 5500.

“Physiological Features of Dysarthria in Friedreich’s Ataxia,” Cahill, Louise, M., Deborah G. Theodoros, Bruce E. Murdoch, and John MacMillan, Asia Pacific Journal of Speech, Language and Hearing, Vol. 8, No. 3, pp. 221-228, 2003.

Abstract: Due to the paucity of literature concerning the motor speech impairment in persons with Friedreich’s ataxia (FA), the air of the study was to investigate the perceptual and physiological features of dysarthria in a 30-year-old male with FA, 22 years post diagnosis. The four speech subsystems were comprehensively evaluated using physiological measures of respiratory (Respitrace), laryngeal (Laryngograph, Aerophone II), velopharyngeal (Nasometer) and articulatory (lip and tongue pressure transduction systems) function. Perceptual speech evaluations included the Frenchay Dysarthia Assessment, the Assessment of Intelligibility of Dysarthric Speech and a perceptual analysis of a speech sample. The findings were compared with those of non-neurologically impaired controls, matched for age and sex. Results revealed marked impairment in respiratory, velopharyngeal and articulatory function, and mild laryngeal dysfunction. Based on these results the subject was rated as displaying a moderate mixed dysarthria (flaccid/ataxic), with a mild to moderate decrease in overall intelligibility. The results of the assessments will be discussed in relation to the possible effects of FA on motor speech function.

Researchers in this study used Kay’s Aerophone II, Model 6800 for aerodynamic evaluation; velopharyngeal function was assessed using Kay’s Nasometer, Model 6400.

“Task Specificity in Adductor Spasmodic Dysphonia Versus Muscle Tension Dysphonia,” Nelson, Roy, Manon Gouse, Shannon C. Mauszycki, Ray M. Merrill, and Marshall E. Smith, Laryngoscope, Vol. 115, pp. 311-316, February 2005.

Objectives/Hypothesis: Adductor spasmodic dysphonia (ADSD) has been characterized as a “task specific” laryngeal dystonia, meaning that the severity of dysphonia varies depending on the demands of the vocal task. Voice produced in connected speech as compared with sustained vowels is said to provoke more frequent and severe laryngeal spasms. This study examined the diagnostic value of “task specificity” as a marker of ADSD and its potential to differentiate ADSD from muscle tension dysphonia (MTD), a functional voice disorder than can often masquerade as ADSD.

Study Design: Case-control study.

Methods: Five listeners, blinded to the purpose of the study, used a 10 cm visual analogue scale to rate dysphonia severity of subjects with ADSD (n = 36) and MTD (n = 45) producing either connected speech or a sustained vowel “ah.” 

Results: In ADSD, dysphonia severity for connected speech (M = 6.22 cm, SD = 2.56) was rated significantly more severe than sustained vowel productions (M = 4.8 cm, SD = 2.8 [t (35) = 3.67, P < .001]). In MTD, however, no significant difference in severity was observed for the connected speech sample (M = 5.98 cm, SD = 2.83 versus the sustained vowel M = 5.86 cm, SD = 2.87 [t (44) = 0.378, P = .707]). The receiver operating characteristic (ROC) curve, an index of the accuracy of task specificity as a diagnostic marker, revealed that a 1 cm difference criterion correctly identified 53% of ADSD cases (sensitivity) and 76% of MTD cases (specificity) (X2 (1) = 6.88, P = .0087).

Conclusions: Reduced dysphonia severity during sustained vowels supports task specificity in ADSD but not MTD and highlights a valuable diagnostic marker whose recognition should contribute to improved diagnostic precision.

In this study, the connected speech and sustained vowel samples were digitized using Kay’s Multi-Speech, Model 3700.

“Impact of Topical Anesthesia on Acoustic Characteristics of Voice During Laryngeal Telescopic Examination,” Yang, Cheng-Chien and Sheng Hwa Chen, Otolaryngology-Head and Neck Surgery, Vol. 132, No. 1, pp. 110-114, January 2005.

Objective: The purposes of this study are to investigate the impact of topical anesthetic alone and with concurrent laryngeal telescopic examination on acoustic characteristics of vocal fold function. Comparison with phonation in controlled conditions may imply diagnostic information from the examination.

Study Design: Thirty males evaluated as having a normal voice were included in the study. The subjects were asked to phonate sustained /i/ with a naturally comfortable pitch and loudness in three consecutive experimental sequences as “control condition,” Acoustic analysis of fundamental frequency, jitter, shimmer, and harmonic to noise ration in the three different conditions were executed.

Results: The mean and standard deviation of Fo in control condition, anesthetic condition, and telescopic condition were 130.1 ±. 18.5 Hz, 125.7 ± 19.7 Hz, and 172.2 ± 35.1 Hz, respectively. The telescopic condition showed more negative change than that in control condition and anesthetic condition in other parameters. There was a significant difference (P < 0.001) between control condition and telescopic condition in all four parameters.

Conclusions: This study showed that anesthesia has little effect on voice performance for subjects with a normal voice. On the other hand, the acoustic characteristics changed significantly during telescopic performance. When doing interpretation of acoustic data, the abnormality of the acoustic characteristics might be the result of the procedures and not reflect vocal pathology. Laryngeal variations due to manipulation of telescope should be ruled out.

Researchers in this study used Kay’s Rhinolaryngeal Stroboscope, Model 9100, for laryngeal examinations and Kay’s Computerized Speech Lab, Model 4300B, for acoustic analysis.

“Outcome of Laryngeal Manual Therapy in Four Dutch Adults with Persistent Moderate-to-Severe Vocal Hyperfunction: A Pilot Study,” Van Lierde, Kristiane M., Sophia De Ley, Gregory Clement, Marc De Bodt, and Paul Van Cauwenberge, Journal of Voice, Vol. 18, No. 4, pp. 467-474, December 2004.

A relatively new management strategy for the treatment of voice disorders in the use of laryngeal manual therapy. The main purpose of the present pilot study is to document the outcome of vocal quality after a well-defined laryngeal manual therapy (LMT) program. Four Dutch professional voice users with a persistent moderate or severe muscle tension dysphonia were studied pretreatment (1 week before LMT) and posttreatment (1 week) after completion of manual therapy (25 sessions). These subjects had received several months of traditional voice therapy, without any success. To measure and compare, the effect of LMT objective and subjective assessment techniques were used. Perceptual voice assessment included a perceptual rating of the voice using the GRBAS scale. Furthermore, the vocal quality in this population was modeled by means of the Dysphonia Severity Index (DSI). All of the subjects selected for LMT showed improvement in perceptual vocal quality and DSI values. As the DSI is weighted variable including aerodynamic and acoustic measure, small improvements (closer to 5) are very indicative of vocal quality improvement. The use of LMT in professional voice users with persistent moderate-to-severe muscle tension dysphonia, especially in some subjects who have not responded to traditional voice therapy, is supported by this pilot study.

Kay’s CSL, Model 4300B, was used in conjunction with the Multi-Dimensional Voice Program (MDVP), Model 5105, and Voice Range Profile, Model 4326, to assess vocal quality in this study.

“Fragments of a Greek Trilogy: Impact on Phonation,” Ferrone, Carol, Grace Leung, and Lorraine Olson Ramig, Journal of Voice, Vol. 18, No. 4, pp. 488-499, December 2004.

This study documents the vocal characteristics of an actor before and after a series of eight performances involving extended voice use. The hypothesis was that this type of extended voice use would result in symptoms of vocal abuse and that damage to the actor’s voice would be evident in measures made after the performance series. Three pre-performance and three post-performance speech samples were gathered and analyzed using the CSL and Visi-Pitch II. Measurements taken included maximum phonational range; maximum sustained phonation; fundamental frequency during reading; maximum intensity levels; sound pressure levels for soft, moderate, and loud productions of sustained /a/; and perturbation including jitter, shimmer, harmonics-to-noise ratio, and an s/z ratio. Pre- and post-performance samples of the “Rainbow passage” and sustained vowel phonation were rated by a group of blinded listeners that included professional voice trainers and speech pathologists. In addition, sample lines from the performance were played for the listeners to judge whether this technique would result in symptoms of vocal abuse. Eleven out of 12 professional voice trainers rated that this technique would result in symptoms of vocal abuse. The data revealed post-performance improvement in phonational range, maximum intensity levels, perturbation measures, and s/z ratio. Measures of maximum sustained phonation, fundamental frequency, and sound pressure levels remained stable. Videoendoscopy revealed normal function of the larynx and vocal folds.

Kay’s Computerized Speech Lab (CSL), Model 4300B, was used for analyzing the Rainbow Passage and lines from the play. Kay’s Visi-Pitch II, Model 3300, was used to obtain measures of average fundamental frequency, jitter, shimmer, and noise-to-harmonic ratio on samples of a sustained /a/. Visi-Pitch II was also used to measure maximum phonational range.

“Voice Quality After Carbon Dioxide Laser and Conventional Surgery for T1A Glottic Carcinoma,” Schindler, Antonio, Francesca Palonta, Giuliana Preti, Francesco Ottaviani, Oskar Schindler, and Andrea Luigi Cavalot, Journal of Voice, Vol. 18, Number 4, pp. 545-550, December 2004.

The different types of small vocal fold tumor therapy allow the preservation of respiration and deglutition; the quality of phonation is the most important criterion for the patient. The aim of the study is to compare vocal function after treatment of T1a tumors by conventional and laser cordectomy. Fifty-seven male patients were included in the study: 27 underwent conventional cordectomy using an external approach, and 30 underwent an endoscopic microscopic laser cordectomy. Videolaryngoscopy were performed for each subject, and the maximal phonation time was measure. Spectrograms were recorded, and perturbation analysis was performed if a clear harmonic structure was visible. Voices were perceptually rated by two experienced phoniatricians using the GRBAS scale. Even though a slightly better voice was found after conventional surgery throughout the data, no statistically significant difference was measured in the two groups. The data on voice outcome per se do not indicate the selection of one surgical approach over another.

Kay’s Computerized Speech Lab, (CSL), Model 4300, and Multi-Dimensional Voice Program, Model 5105, were used to perform objective voice evaluations in this study.

“Study of Lubricant-Induced Changes in Chronic Snorers,” Wijewickrama, Rohan, C., David Blalock, and James W. Mims, Otolaryngology-Head and Neck Surgery, Vol. 131, No. 5, pp. 606-609, November 2004.

Objective: The efficacy of many of the noninvasive treatments for snoring has not been evaluated in controlled trials. This paper seeks to evaluate the efficacy of an oil-based spray in the treatment of snoring, in a double-blinded, placebo-controlled, crossover trial using objective acoustic analysis and subjective questionnaires.

Study Design and Setting: Participants were randomized to use both oil-based oral spray (treatment) and water-based oral spray (placebo) during a two-night in-home study period. Questionnaires were completed by participant and bed-partner in addition to audio-tape recordings which were analyzed for frequency, duration, and mean energy of snoring.

Results: Greatest snoring rate demonstrated 30% = benefit; 40% = no change; 30% = adverse effect (n = 20). Percent time snoring yielded: 30% benefit; 15% no change; 55% adverse effect (n = 12): benefit = 17%, no change = 33%, adverse effect = 50%. Bed-partner observations (n = 17) demonstrated 37% = benefit; 38% = no change; 25% adverse effect.

Conclusion/Significance: Objective and subjective evaluation of the performance of the oil-based Snoreless spray in comparison to placebo demonstrated a lack of efficacy in snoring reduction.

In this study, the audiotaped tokens (snores) were analyzed using Kay’s Computerized Speech Lab (CSL), Model 4300B.

“Factors Predicting Patient Perception of Dysphonia Caused by Benign Vocal Fold Lesions,” Behrman, Alison, Lucian Sulica, and Tina He, Laryngoscope, Vol. 114, pp. 1693-1700, October 2004.

Objective/Hypothesis: To access factors that may be predictive of patient perception of dysphonia severity, as quantified by the Voice Handicap Index (VHI) score. We hypothesize that 1) level of vocal demand; 2) auditory-perceptual evaluation of dysphonia severity; and 3) vocal function, as defined by phonatory glottal closure and mucosal wave vibration, are the most significant predictors of VHI score.

Study Design: Retrospective review of 100 patients with benign vocal fold lesions.

Methods: Variables assessed for predictive value to VHI score are level of vocal demands, auditory-perceptual evaluation of dysphonia severity, integrity of mucosal wave vibration and phonatory glottal closure, lesion type, duration of current complaint, smoking, age, and sex. Harmonic to noise ratio was assessed in a subset of 50 patients.

Results: Patients with routine voice use had significantly lower VHI scores than those with more intensive (nonsinging/acting) vocal demands. Patients who quit smoking had greater VHI scores than those who currently smoke or never started. Patients with long-standing dysphonia tended to have lower VHI scores than those with shorter duration vocal complaints. Auditory-perceptual assessment of dysphonia severity and harmonic to noise ratio were weak predictors of VHI score. Age, sex, lesion type, phonatory glottal closure, and mucosal wave vibration were not significant predictors of VHI score.

Conclusions: Patient perception of dysphonia severity is independent of many factors commonly assessed during the evaluation of voice disorders. It appears to be an import independent element in the assessment of the effect of a benign vocal fold lesion and critical to therapeutic decision-making.

In this study, acoustic data were obtained using an external microphone input to Kay’s Digital Video Stroboscopy System and sampled at 51.2 k samples/s before the endoscopic examination. The digital files were then analyzed using Kay’s Computerized Speech Lab (CSL).

“Voice Changes after Androgen Therapy for Hypogonadotrophic Hypogonadism,” Akcam, Timur, Erol Bolu, Albert L. Merati, Coskun Durms, Mustafa Gerek, and Yalcin Ozkaptan, Laryngoscope, Vol. 114, pp. 1587-1591, September 2004.

Objectives/Hypothesis: Males with isolated hypogonadotropic hypogonadism (IHH) fail to undergo normal sexual development, including the lack of masculinization of the larynx. The objective of this study was to measure the mean vocal fundamental frequency (Mfo) in IHH patients and determine the impact of androgen treatment. An additional aim was to compare the Mfo between IHH patients and controls.

Study/Design: Prospective observational study. 

Methods: Twenty-four patients with IHH were identified along with 30 normal males and females. Voice recordings were obtained on all subjects. Androgen therapy was administered to the IHH patients. The Mfo and serum sex hormone levels were measured before treatment and at intervals during therapy. These results were compared with the pretreatment data within the IHH group. Voice parameters were also compared between the pre- and posttreatment IHH patients and the normal males and females.

Results: The Mfo in untreated IHH patients was 229 ± 41 Hz. This was intermediate between the normal male (150 ± 22 Hz, P < .001) and normal female patients (256 ± 29 Hz, P < .01). After treatment, the Mfo in the IHH group decreased to 173 ± 30 Hz (P < .0001); indeed, their posttreatment Mfo approached that of normal males (P < .08). Serum hormone levels responded to the injected testosterone, but these levels did not directly correlate with Mfo.

Conclusions: Mfo in IHH patients is intermediate between normal male and female levels. After treatment with testosterone, these values approach the range of normal males. This prospective study details the impact of androgens on the larynx and vocal function in patients with IHH.

Kay’s CSL, in conjunction with the Multi-Dimensional Voice Program (MDVP), Model 5105, was used to determine the acoustic parameters in this study.

“Quality-of-Life Outcomes Following Laryngeal Endoscopic Surgery for Non-Neoplastic Vocal Fold Lesions,” Johns, Michael M., C. Gaelyn Garrett, Joanna Hwang, Robert H. Ossoff, and Mark S. Courey, Annals of Otology, Rhinology & Laryngology, Vol. 113, Number 8, pp. 597-601, August 2004.

Preservation of the vocal fold cover during laryngeal surgery should optimize vocal outcomes for patients with benign glottal lesions. The aim of the study was to evaluate changes in the quality of life, perceptual voice evaluation, and acoustic and aerodynamic measures of patients before and after endoscopic laryngeal microsurgery for true vocal fold cysts, polyps, and scarring. Pre-operative and postoperative Voice Handicap Index (VHI) scores, Short form 36 scores, and perceptual, acoustic, and aerodynamic voice measures were obtained prospectively from 42 patients who underwent phonomicrosurgery from February 2000 through May 2003. The mean (±SD) preoperative VHI was 49.6 ± 21. The mean postoperative VHI score at a minimum of 3 months after surgery decreased to 26.8 ± 21 (p < .001). When divided by lesion type, VHI scores improved significantly after surgery for vocal fold polyps and cysts. Although patients with vocal fold scarring demonstrated improvement in VHI scores after surgery, statistical significance was not achieved. For the entire group, the Short Form 36 scores were not significantly different from US norms either before or after operation. The acoustic data showed statistically significant decreases in jitter (2.05% to 1.26%), shimmer (7.06% to 4.03%), and noise-to-harmonics ratio (0.18 to 0.13) after surgery (p < .05) in female patients. The upper pitch limit increased after surgery in women (495.3 Hz to 654.9 Hz, p < .001). These results indicate that the voice-related quality of life and some acoustic parameters improved significantly for patients who have undergone laryngeal microsurgery for vocal fold cysts and polyps. Vocal fold scarring remains a difficult clinical problem with less favorable outcomes following surgical treatment in the patients set.

In this study, acoustic data were collected and analyzed using Kay’s CSL, Model 4300, in conjunction with Kay’s Multi-Dimensional Voice Program (MDVP).

“The Effect of Task on Determination of Habitual Loudness,” Zraick, Richard I., Whitney Marshall, Laura Smith-Olinde, and James C. Montague, Journal of Voice, Vol. 18, Number 2, pp. 176-182, June 2004.

The purpose of this study was to investigate if there is an effect of task on determination of habitual loudness. Four tasks commonly used to elicit habitual loudness were compared (automatic speech, elicited speech, spontaneous speech, and reading aloud). Participants were adult female speakers (N = 30) with normal voice. A one-way analysis of variance (ANOVA) revealed a statistically significant (p < 0.05) effect of task, with post-hoc analyses indicating that there was a statistically significant difference in habitual loudness elicited via automatic versus spontaneous speech (p < 0.05), and automatic speech versus reading aloud (p < 0.001). The issue of how habitual loudness is defined is considered. Implications of the use of one task for determination of habitual loudness are discussed, as in the possibility of a task effect on determination of other clinically useful vocal parameters.

In this study, Kay’s Visi-Pitch II, Model 3300, was used to determine whether each subject demonstrated normal vocal quality and speaking fundamental frequency and to obtain and analyze measurements of habitual vocal intensity.

“Vocal Aging and the Impact on Daily Life: A Longitudinal Study,” Verdonck-de Leeuw, Irma M. and Hans F. Mahieu, Journal of Voice, Vol. 18, Number 2, pp. 193-202, June 2004.

 Longitudinal studies on vocal aging are scarce, and information on the impact of age-related voice changes on daily life is lacking. This longitudinal study reports on age-related voice changes and the impact on daily life over a time period of 5 years on 11 healthy male speakers, age ranging from 50 to 81 years. All males completed a questionnaire on vocal performance in daily life, and perceptual and acoustical analyses of vocal quality and analyses of maximum performance tasks of vocal function (voice. range profile were performed. Results showed a significant deterioration of the acoustic voice signal as well as increased ratings on vocal roughness judged by experts after the time period of 5 years. An increase of self-reported voice instability and the tendency to avoid social parties supports these findings. Smoking males had a lower speaking fundamental frequency compared with nonsmoking males, and this seemed reversible for males who stop smoking. This study suggests a normal gradual vocal aging process with clear consequences in daily life, which should be taken into consideration in clinical practice as well as in studies concerning communication in social life.

Researchers in this study performed acoustic analyses of voice quality using Kay’s MDVP software in conjunction with the CSL, Model 4300B.

Measures of cepstral peak prominence, using the smoothing algorithm and linear regression analysis software developed by Hillenbrand have been shown to be reliable predictors of dysphonia in voice samples. Recently, the Computerized Speech Laboratory [(CSL) Kay Elemetrics, Pine Brook, New Jersey] has introduced cepstral analysis as a component of that software package. The cepstral peak, in this instance, is calculated by the voice clinician analyzing the phonatory sample by subtracting the value of the peak from the apparent baseline signal. This study compares the ability of cepstral peak values calculated from the CSL software to predict dysphonia reliably with that of the values produced by the smoothing algorithm and linear regression analysis of Hillenbrand. The results of this study show that linear regression analysis is an important step in calculating the cepstral peak prominence, thus limiting the usefulness of software programs that do not employ this step.

The voice samples in this study underwent cepstral analysis using Kay's core CSL software accessed from samples acquired within MDVP (Advanced version.

“Association between birth control pills and voice quality,” Amir, Ofer and Liat Kishon-Rabin, Laryngoscope, Vol. 114, pp. 1021-1026, June 2004.

Objective/Hypothesis: The objective was to extend our knowledge of the effect of birth control pills on voice quality in women based on various acoustic measures.

Study Design: A longitudinal comparative study of 14 healthy young women over a 36- to 45-day period.

Methods: Voices of seven women who used birth control pills and seven women who did not were recorded repeatedly approximately 20 times. Voice samples were analyzed acoustically, using an extended set of frequency perturbation parameters (jitter, relative average perturbation, pitch period perturbation quotient), amplitude perturbation parameters (shimmer, amplitude average perturbation quotient), and noise indices (noise-to-harmonics ratio, voice turbulence index).

Results: Voice quality and stability were found to be better among the women who used birth control pills. Lower values were found for all acoustic measures with the exception of voice turbulence index. Results also provided preliminary indication for vocal changes associated with the days preceding ovulation.

Conclusions: In contrast to the traditional view of oral contraceptives as a risk factor for voice quality, and in keeping with the authors’ previous work, the data in the present study showed that not only did oral contraceptives have no adverse effect on voice quality but, in effect, most acoustic measures showed improved voice quality among women who used the birth control pill. The differences in the noise indices between groups may also shed light on the nature of the effect on vocal fold regulation of vibration than on glottal adduction.

Kay's CSL, Model 4300B, and Multi-Dimensional Voice Program (MDVP) were used to conduct the acoustic analyses in this study.

“Medialization laryngoplasty with strap muscle transposition for vocal fold atrophy with or without sulcus vocalis,” Su, Chih-Ying, Shang-Shyue Tsai, Jeng-Fen Chiu, and Chu-An Cheng, Laryngoscope, Vol. 114, pp. 1106-1112, June 2004.

Objective: Vocal fold atrophy with or without sulcus vocalis may result in a spindle-shaped glottal incompetence (SGI). Because of varying drawbacks with all existing materials (e.g., Silastic block, Teflon, fat, etc.) used for medialization or augmentation of the atrophic vocal folds, there is a need to supplant these materials with a more stable, autologous tissue to correct the SGI.

Study Design: Thirty-two patients with vocal fold atrophy underwent medialization laryngoplasty with strap muscle transposition.

Methods: Under local or general anesthesia, the thyroid lamina on the more affected side was vertically incised 5 mm off the midline. The inner perichondrium was carefully elevated fro the overlying thyroid ala. Care was taken not to enter the laryngeal lumen. After dividing the thyrohyoid and cricothyroid membranes, the lamina was retracted laterally. To accommodate the muscle flap more easily, the caudal edge of the lamina was trimmed using a small burr. A bipedicled strap muscle flap was then transposed into the space between the lamina and the paraglottic soft tissue. The thyroid cartilages were carefully sutured back in place. All patients underwent pre- and post-operative voice evaluations including laryngostroboscopy, perceptual assessment, and acoustic and aerodynamic analyses. Patients who had been followed up for more than 3 months were enrolled in the study.

Results: A total of 27 of the 3 patients with complete pre- and postoperative voice function measurements were included in the analysis. Vocal improvement was demonstrated in 26 of these 27 (97%) patients. No dyspnea or other major complications were noted in any patients.

Conclusions: The results indicate that medialization laryngoplasty with strap muscle transposition is a prosthesis-free, safe, and effective technique for correcting SGI caused by vocal fold atrophy.

Videolaryngostroboscopy was performed pre- and post-operatively using Kay’s RLS, Model 9100, stroboscopic light source. Kay’s CSL, Model 4300B, and Aerophone II, Model 6800, were also used in this study to perform the acoustic and aerodynamic analyses, respectively.

“Beware of the ‘telephone effect’: the influence of telephone transmission on the measurement of Formant Frequencies,” Künzel, Hermann J., Forensic Linguistics, Vol. 8, pp. 80-112, November 2001.

Abstract: Speech scientists often have to work with speech signals that have been transmitted over the telephone. Although the acoustic properties of telephone transmission such as the band-pass filter characteristics are well know, little attention has been paid to their effect on the measurement of speech parameters. This study deals with artifacts introduced by the lower cut-off slope of the transmission channel on vowel formants. For theoretical reasons, frequency components may be assumed to be attenuated the lower they are. Therefore F1 of most vowels can be expected to be affected most. Attenuation of the lower components of a formant will necessarily increase the relative weight of the higher components for the determination of a formant and thus cause an artificial upward shift of its center frequency. An empirical investigation with directly and telephone-transmitted samples from ten male and ten female subjects shows that the predicted effect on F1 does in fact occur for all tested vowels except /a/, whose F1 is too high to be affected by the slope of the band-pass. The consequences of measurement errors arising from such artifacts are discusses with special reference to speaker identification and empirical dialectology.

Kay’s Multi-Speech software was used to obtain the relevant acoustic measurements in this study.

“The Effect of Auditory Feedback on Phonation Threshold Pressure Measurement,” Morgan, Michael D., Miguel A. Triana, and Thomas J. Milroy, Journal of Voice, Vol. 18, Number 1, pp. 46-55, March 2004.

The effect of auditory feedback on phonation threshold pressure (P_th) measurement was investigated in 14 females with normal, untrained voices. Two measurement systems (Glottal Enterprises MS 100—circumferentially vented mask and Kay Elemetrics Aerophone II—non-circumferentially vented mask) were examined under three conditions: (1) masked, (2) no mask, and (3) masked with enhanced auditory feedback-acoustic signal placed at ears through headphones. Masked with enhanced auditory feedback, in addition to subject training, significantly lowered P_th values regardless of mask design. The amount of auditory feedback provided by different mask designs was investigated and revealed a significant difference. Clinical significance of different auditory feedback levels provided by the two mask designs was investigated. Direct comparison of the mean values between systems was not possible because of each system’s design and calibration. Comparisons were accomplished by subtracting means of select-paired conditions (masked/no mask; masked/masked plus masked with enhanced auditory feedback) within each system and then comparing these difference scores from the same paired conditions between each system. No clinical significance in difference scores was revealed because of varying amounts of auditory feedback provided by the masks. Results support the use of enhanced auditory feedback, in addition to subject training, when measuring P_th.

In this study, Kay’s CSL, Model 4300B, and Multi-Dimensional Voice Program (MDVP) were used to ensure normal limits for Fo, jitter, and shimmer; Kay’s Real-Time Pitch Program was used to obtain each subject’s habitual pitch; Kay’s Voice Range Profile (VRP) program was used to obtain the nearest semitone to a subject’s habitual pitch; and, Kay’s Aerophone II, Model 6800, was used to acquire oral pressures and airflow measures.

“Outcome of Laryngeal and Velopharyngeal Biofeedback Treatment in Children and Young Adults: A Pilot Study,” Van Lierde, Kristiane M., Sofie Claeys, Marc De Bodt, and Paul Van Cauwenberge, Journal of Voice, Vol. 18, Number 1, pp. 97-106, March 2004.

A relatively new management strategy for the treatment of voice disorders is the use of laryngeal (LB) and velopharyngeal biofeedback (VB). The main purpose of the present pilot study is to document the outcome of vocal and velopharyngeal performances after a well-defined LB and VB treatment. Four subjects were studied pretreatment (1 week before LB or VB treatment) and posttreatment (1 week after the LB or VB treatment). To measure and compare the effect of LB and VB, objective and subjective assessment techniques were used. Perceptual voice assessment included perceptual rating of the voice using the GRBAS scale. Furthermore, the vocal quality in this population is modeled by means of the Dysphonia Severity Index. For the objective assessment of nasal resonance, the Nasometer and the Glatzel test were used. A perceptual evaluation of speech, the Gutzmann test, and the tests from Bzoch were used as subjective assessment techniques. Both patients selected for LB and VB treatment showed improvement of their performances. The resulting improvement, as measured by means of an objective approach, is in agreement with the perceived (auditory) improvement of voice and resonance. The use of LB and VB treatment in patients, especially in some subjects who are not responding to traditional voice or velopharyngeal therapy, must be encouraged.

Researchers in this study used Kay’s Multi-Dimensional Voice Program (MDVP) to obtain measures of highest frequency, lowest intensity, maximum phonation time (MPT) and jitter. Kay’s Nasometer was used to obtain nasalance values.

“Relationship Among Glottal Area, Static Supraglottic Compression, and Laryngeal Function Studies in Unilateral Vocal Fold Paresis and Paralysis,” Bielamowicz, Steven, Ritu Kapoor, Jerome Schwartz, and Sheila V. Stager, Journal of Voice, Vol. 18, Number 1, pp. 138-145, March 2004.

In this study, we evaluated the relationship between laryngeal function measures and glottal gap ratio and normalized measures of supraglottic behaviors in patients with unilateral vocal fold paresis (UVFP). Thirty-one patients were found to have unilateral vocal fold paresis by videoendoscopy and laryngeal electromyography, and 13 controls participated in this study. Patients with UVFP demonstrated significantly larger glottal gap ratios (p = 0.016) than control subjects. The nonparalyzed or contralateral vocal fold was associated with significantly more static false vocal fold compression (p = 0.03) compared with the paralyzed vocal fold or with the controls. Patients with unilateral vocal fold paresis were divided into subgroups: those with normal or abnormal maximum phonation time, flow, or pressure measures. Smaller glottal gap ratios were identified in patients with normal maximum phonation times and flow measures. Greater false vocal fold activity was identified in unilateral vocal fold paresis patients with normal laryngeal function measures than in unilateral vocal fold paresis patients with abnormal measures. These findings suggest that some patients with documented unilateral paresis and glottal incompetence can compensate for vocal fold weakness such that their acoustic and aerodynamic measures are normal.

All subjects in this study were examined by transnasal fiberoptic laryngoscopy using Kay’s RLS, Model 9100, light source. Kay’s Model 9105, 70o rigid endoscope was also used to visualize the larynx of each subject. Still images were digitized using Kay’s videostroboscopy software, ver. 1.6.

“Spastic/Spasmodic vs. Tremulous Vocal Quality: Motor Speech Profile Analysis,” Lundy, Donna, S., Soham Roy, Jun W. Xue, Roy R. Casiano, and Daniel Jassir, Journal of Voice, Vol. 18, Number 1, pp. 146-152, March 2004.

Strained, strangled, and tremulous vocal qualities that are typically seen in adductor spasmodic dysphonia (ADSD), voice tremor (Tremor), and the spastic dysarthria of amyotrophic lateral sclerosis (ALS) may sound similar and be difficult to differentiate. The purpose of this study was to determine if these vocal qualities of neurologic origin could be differentiated on the basis of acoustic and motor speech parameters. Three groups of subjects (ADSD, ALS, and Tremor) were analyzed by the Motor Speech Profile System (Kay Elemetrics, Lincoln Park, NJ) for fundamental frequency (Fo), standard deviation of Fo, diadochokinetic rate (ddk), standard deviation of ddk, mean intensity and standard deviation of ddk, frequency and amplitude variability in connected speech, and speaking rate in connected speech. Profiles of the three groups are presented with the significant features that differentiated one from the other.

All patients in this study underwent acoustic/motor speech analysis using the Motor Speech Profile, Model 4341, a software option for Kay’s Computerized Speech Lab.

“The Importance of the Voice in Male-to-Female Transsexualism,” Neumann, Kerstin and Cornelia Welzel, Journal of Voice, Vol. 18, Number 1, pp. 153-167, March 2004.

Transsexuality is a complex, permanent transposition involving a paradoxical feeling of belonging to the opposite sex. Furthermore, in the case of male-to-female transsexuals, the unchanged male voice, which is at odds with the female outward appearance, poses a serious obstacle to full social integration of the woman.

One way of permanently raising the fundamental frequency, requiring little effort, is modified cricothyroidopexy via miniplates, which has been used in our hospital since 1993 following a technique developed by Isshiki (thyroplasty type IV).

Until now, this operation has been performed on 67 female patients. To record the anatomical-morphological and functional data, preoperatively, post-operatively, and a year after the operation, a detailed voice diagnosis was made, laryngoscopy was carried out, X-rays were taken, and computer-assisted tomography was used to examine the larynx.

Thus far, the functional results have been good. On average, the fundamental frequency has been raised by about one fourth. Whereas none of the female patients had a female-speaking voice before the operation, after the operation, about 30% of the patients’ voices were in the female range, and 32% had at least a neutral-sounding voice.

Kay’s CSL, Model 4300B, was used to measure the voice range profile of subjects in this study.

“Muscle tension dysphonia in patients who use computerized speech recognition systems,” Olson, David, E.L., Raul M. Cruz, Krzysztof Izdebski, and Tracey Baldwin, Ear, Nose, and Throat Journal, Vol. 83, Number 3, pp. 195-198, March 2004.

The use of speech recognition systems as a replacement for other types of transcription systems is increasing rapidly, partly because many people are unable to use conventional keyboards as a result of upper-extremity repetitive strain injury (RSI). However, the frequent or continuous use of such systems can cause muscle tension dysphonia in some patients. The scientific literature suggests that there is an association between upper-extremity RSI and muscle tension dysphonia. We present a retrospective case series of five patients with workplace upper-extremity RSI who developed muscle tension dysphonia soon after they began using discrete computerized speech recognition software. The diagnosis of dysphonia was based on laryngovideostroboscopy, acoustic analyses, and voice load testing. All patients had normal voice when using everyday speech, but speaking into the computer resulted in the rapid onset of aperiodicity, strain, and a decrease in fundamental frequency. In three of the five patients, laryngovideostroboscopy showed posterior glottic overapproximation, but no other abnormalities. Treatment was centered on voice therapy and avoidance of long periods of using computerized speech recognition systems. The condition of three of the five patients improved with therapy. We conclude that computer speech recognition programs can lead to the onset of muscle tension dysphonia in some patients. These patients can be successfully treated with voice therapy.

Kay’s CSL, Model 4100, and a Kay stroboscopy system were used by researchers in this study to perform acoustic analysis and laryngovideostroboscopy, respectively.

“Laryngeal Function and Vocal Fatigue After Prolonged Reading in Individuals with Unilateral Vocal Fold Paralysis,” Kelchner, Lisa N., Linda Lee, and Joseph C. Stemple, Journal of Voice, Vol. 17, Number 4, pp. 513-528, December 2003.

The purpose of the present study was to examine the effect of prolonged loud reading, intended to induce fatigue, on vocal function in adults with unilateral vocal fold paralysis (UVFP). Subjects were 20 adults, 37-60 years old, with UVFP secondary to recurrent laryngeal nerve paralysis. Subjective ratings and instrumental measures of vocal function were obtained before and after reading. Statistical analysis revealed subjects rated their vocal quality and physical effort for voicing more severely following prolonged loud reading, whereas expert raters did not detect a significant perceptual difference in vocal quality. Reading fundamental frequency (Fo) was significantly increased following prolonged loud reading, as were mean airflow rates at all pitch conditions. Maximum phonation times for comfort and low pitches significantly decreased during posttests. Multiple regression analyses revealed significant associations between ratings of posttest physical effort and select posttest measures. Interpretation of results indicates the prolonged loud reading task was successful in vocally fatiguing most of the UVFP subjects. Key physiologic correlates of vocal fatigue, in individuals with UVFP, include further reduction of glottic efficiency, resulting in decreased regulation of glottic airflow and a temporary destabilization of speaking fundamental frequency.

Kay’s Visi-Pitch was used to collect data for measures of fundamental frequency and intensity during running speech; data for fundamental frequency, intensity, and noise-to-harmonic ratio were collected for sustained vowel /ah/ using Kay’s MDVP.

“Effects of Vocal Training on the Acoustic Parameters of the Singing Voice,” Mendes, Ana P., Howard B. Rothman, Christine Sapienza, and W.S. Brown, Jr., Journal of Voice, Vol. 17, Number 4, pp. 529-543, December 2003.

Vocal training (VT) has, in part, been associated with the distinctions in the physiological, acoustic, and perceptual parameters found in singers’ voices versus the voices of nonsingers. This study provided information on the changes in the singing voice as a function of VT over time. Fourteen college voice majors (12 females and 2 males; age range, 17-20 years) were recorded while singing, once a semester, for four consecutive semesters. Acoustic measures included fundamental frequency (Fo) and sound pressure level (SPL) of the 10% and 90% levels of the maximum phonational frequency range (MPFR), vibrato pulses per second, vibrato amplitude variation, and the presence of the singer’s formant. Results indicated that VT had a significant effect on the MPFR, Fo and SPL of the 90% level of the MPFR and the 90-10% range increased significantly as VT progressed. However, no vibrato or singers’ formant differences were detected as a function of training. This longitudinal study not only validates previous cross-sectional research, ie, that VT has a significant effect on the singing voice, but also it demonstrates that these effects can be acoustically detected by the fourth semester of college vocal training.

In this study, Kay’s CSL, Model 4300B, was used to perform the acoustic analyses.

“Tracking Outcomes after Phonosurgery for Sulcus Vocalis: A Case Report,” Welham, Nathan V., Bernard Rousseau, Charles N. Ford, and Diane M. Bless, Journal of Voice, Vol. 17, Number 4, pp. 571-578, December 2003.

Outcomes data after a surgical or behavioral intervention should be tracked until stability is reached. Often it is unclear how long patients should be followed and at what point an outcome can be considered stable. These issues have implications for treatment decision making, efficacy measurement, and the design of research studies. Vocal function data were collected 24 hours before and at 1, 6, and 12 months after phonosurgery for sulcus vocalis. One data series was collected daily during the first month after surgery, providing a unique opportunity to study voice changes in the immediate postoperative period. The different vocal function indices (acoustic, perceptual, videostroboscopic, aerodynamic, psychosocial) demonstrated a general pattern of improvement after intervention; however, they appeared to reach stability at different times. This report reinforces the value of following patients until complete outcome stability.

Laryngeal imaging was performed using a Kay RLS, Model 9100, attached to a rigid endoscope; Kay’s VRP, in conjunction with CSL, Model 4300B, was used to measure Fo range.

“Early Results of Transcutaneous Injection Laryngoplasty with Micronized Acellular Dermis Versus Type-I Thyroplasty for Glottic Incompetence Dysphonia Due to Unilateral Vocal Fold Paralysis,” Lundy, Donna S., Roy R. Casiano, Mark E. McClinton, and Jun W. Xue, Journal of Voice, Vol. 17, Number 4, pp. 589-595, December 2003.

Medialization thyroplasty (type I) has become the gold standard to improve glottic closure due to unilateral vocal fold paralysis. A newer injection method utilizing homologous collagen from cadaveric human tissue has been described as an attractive alternative as no donor site is required, there is a very low risk of hypersensitivity, and the intact, acellular collagen fibers may suffer a reduced long-term reabsorption rate. Preliminary results on eight patients comparing presurgical and postsurgical parameters (perceptual, stroboscopic, acoustic, and aerodynamic) revealed comparable results when compared with a control group of individuals, age- and sex-matched, that had undergone standard medialization thyroplasty (type I). Further study is needed to assess the long-term results with this minimally invasive method of vocal fold medialization.

Researchers in this study used a Kay stroboscopy system to assess the degree of glottal closure; acoustic analysis, including jitter rate and noise-to-harmonic ratio, was performed using Kay’s MDVP.

“Maxillary obturators: the relationship between patient satisfaction and speech outcome,” Rieger, Jana M., John F. Wolfaardt, Naresh Jha, and Hadi Seikaly, Head and Neck, pp. 895-903, November 2003.

Abstract:

Background: Patient satisfaction with a maxillary obturator has been studied in relation to extent of surgical defect, sociodemographic characteristics, scores on mental health inventories, and psychosocial adjustment to illness scales. However, review of the literature reveals limited study of the relationship between patient satisfaction with an obturator and clinical speech outcome measures. The purpose of this study is to relate patient satisfaction scores obtained by questionnaire with those obtained by means of clinical speech measurements.

Methods: Acoustical, aeromechanical, and perceptual measurements of speech were collected for 20 patients after receiving a definitive obturator. Patient satisfaction with their obturator was later measured with the Obturator Functioning Scale (OFS).

Results: Results reveal that poorer aeromechanical speech results were associated with patient-reported avoidance of social events, whereas lower speech intelligibility outcomes were related to overall poorer perception of speech function on the OFS. Several background patient characteristics were significantly related to several responses on the OFS and to the aeromechanical assessment outcomes.

Conclusions: Results from instrumental assessments of speech seem to be informative regarding not only speech outcome but also a patient’s satisfaction with the obturator. Consideration of background patient characteristics is important when interpreting both clinically obtained and patient-perceived outcomes.

Kay’s Nasometer, Model 6200, was used to sample and evaluate the resonance balance of oral and nasal acoustic speech energy in this study.

“Cymetra injection for unilateral vocal fold paralysis,” Karpenko, Andrew N., Robert J. Meleca, James P. Dworkin, and Robert J. Stachler, Annals of Otology, Rhinology & Laryngology, Vol. 112, Number 11, pp. 927-934, November 2003.

Cymetra has shown excellent tissue biocompatibility, a low rate of resorption, and no tissue reactivity when injected for treatment of facial wrinkling. On the basis of these findings, we hypothesize that injection of Cymetra into the thyroarytenoid muscle for treatment of glottal incompetence may demonstrate similar findings and lead to long-term improvement in voice quality and glottal gap closure. Ten patients with breathy dysphonia caused by unilateral vocal fold paralysis underwent transoral injection of Cymetra into the thyroarytenoid muscle. Each subject underwent preoperative and postoperative acoustic analysis, aerodynamic measures, taped voice sampling, and videostroboscopy. Significant improvements were identified in maximum phonation time, relative glottal area, and subjective judgment of glottal competency. These results were not maintained at the 3-month study interval. No significant change in quantitative or subjective voice quality was noted for the study group during the investigation. Resorption of cymetra may play a significant role in contributing to these findings.

Kay’s RLS, Model 9100, was used in the study to observe laryngeal anatomy and phonatory biomechanics. Kay’s Computerized Speech Lab (CSL), Model 4300, and Aerophone II were used to perform the acoustic and speech aerodynamic analysis, respectively.

“Acoustic analysis of autologous fat injection versus thyroplasty in the same patient,” Hartl, Dana M., Ollivier Laccourreye, Jacqueline Vaissière, and Daniel F. Brasnu, Annals of Otology, Rhinology & Laryngology, Vol. 112, Number 11, pp. 987-992, November 2003.

We objectively measured the acoustic effects of treatment of unilateral vocal fold paralysis by injection of autologous fat and by polytetrafluoroethylene throplasty, in the same patient. To our knowledge, this is the first report comparing the two techniques by using the patients’s normal voice as the control. The voice of a male patient was recorded before and after onset of unilateral vocal fold paralysis, after treatment with autologous fat, and after polytetrafluoroethylene throplasty. Acoustic analysis was performed on a long-term average spectrum of text and on the MDVP (Kay Elemetrics) evaluation of the vowel /a/. Jitter and shimmer were not normalized, but they improved to a greater extent after fat injection. The cepstral peak prominence, spectral skewness, and long-term average spectrum returned to preparalytic values after both treatments, but improved to a greater extent after fat injection. This study showed that both techniques can return the voice to preparalytic values. Spectral measurements best reflected the voice improvement. Further prespective studies in a larger number of patients will be necessary to confirm these results and to determine the long-term objective voice outcome obtained with these techniques.

Kay’s CSL Model, 4300B was used for the acoustic analysis in this study; Kay’s MDVP was used to determine jitter, shimmer, degree of voicelessness, and number of unvoiced segments for a 500-ms midvowel token.

“Voice and deglutition functions after the supracricoid and total laryngectomy procedures for advanced stage laryngeal carcinoma,” Dworkin, James Paul, Robert J. Meleca, Mark A Zacharek, Robert J. Stachler, Raza Pasha, G.G. Abkarian, Richard A. Culatta, and John R. Jacobs, Otolaryngology-Head and Neck Surgery, Vol. 129, Number 4, pp. 311-320, October 2003.

OBJECTIVE: This investigation compared speech and deglutition functions after alternative surgical treatments for advanced stage laryngeal carcinoma: the supracricoid laryngectony (SCL) versus the total laryngectomy (TL).

STUDY DESIGN AND SETTING: Cohort investigational Wayne State University School of Medicine.

METHODS: Quantitative studies of laryngeal biomechanics, acoustic and speech aerodynamic features, and deglutition skills of these individuals were coupled to listener and patient self-impressions of speech and voice characteristics for group comparative analyses.

RESULTS: Results revealed that patients from each subgroup performed comparably relative to speech intelligibility and voice quality disturbances. Videostroboscopy of the neoglottal mechanisms in these two populations helped to explain these outcomes. Acoustic and speech aerodynamic testing demonstrated variably abnormal features in both surgical subgroups. Whereas the SCL patients eventually achieved full oral diets, they required many sessions of swallowing therapy to obtain this objective and eliminate tube feeding supplementation. The TL patients did not evidence protracted swallowing difficulties or the need for specific exercises in order to remove their feeding tubes postoperatively. References to organ preservation strategies in lieu of surgical management are included for completeness purposes.

CONCLUSION: The SCL and TL surgical procedures for advanced stage laryngeal carcinoma resulted in equivalent speech and swallowing functional outcomes.

Kay’s CSL, Model 4300, and Aerophone II were used to collect all acoustic and speech aerodynamic data, respectively. Kay’s RLS, Model 9100, was used to observe structure and function of the neoglottis during all phonatory assessments.

“Functional outcomes after primary oropharyngeal cancer resection and reconstruction with the radial forearm free flap,” Seikaly, Hadi, Jana Rieger, John Wolfaardt, Gerald Moysa, Jeffery Harris, and Naresh Jha, Laryngoscope, Vol. 113, pp. 897–904, May 2003.

Objective: To report prospectively collected aeromechanical, acoustical, and perceptual speech outcomes, as well as preliminary swallowing data, in patients having reconstruction with radial forearm free flaps after primary resection for oropharyngeal cancer.

Study Design: Prospective cohort study.

Methods: Acoustical, aeromechanical, and perceptual speech data and swallowing data were gathered at three evaluation times (preoperatively and before and after radiation therapy) for patients treated for oropharyngeal cancer by means of primary resection and reconstruction with a radial forearm free flap. Degree of involvement of the soft palate and base of tongue, along with reconstructive techniques, were entered as between-group factors in the analysis.

Results: There were no significant differences in speech intelligibility between the patient groups based on the degree of palate and tongue resected. However, patients with resections of half or more than half of the soft palate had significantly higher nasalance values and larger velopharyngeal orifice areas than individuals who had less than half of the soft palate resected. Significant within-subject differences were revealed across evaluation times for the dependent variables nasalance, velopharyngeal orifice area, and word intelligibility. Ninety-four percent of the patients were able to resume a normal or soft diet. There was a 6% incidence of aspiration in 128 swallows that were analyzed. The amount of base of tongue resected did not significantly affect any of the speech or swallowing parameters.

Conclusions: Radial forearm free flaps are a good reconstructive option after oropharyngeal cancer extirpation. Our acoustic and aeromechanical results indicated that issues related to quality of the speech signal require further study for resections of half or more than half of the soft palate.

Kay’s Nasometer, Model 6200 was used to collect information regarding resonance balance and to obtain nasalance scores.

“Speech outcomes in patients rehabilitated with maxillary obturator prostheses after maxillectomy: a prospective study,” Rieger J., J. H. and N. Jha, International Journal of Prosthodontics, Vol. 15(2), pp. 139-44, March/April 2002.

PURPOSE: Speech outcome measurements are valuable in guiding treatment and determining the effectiveness of rehabilitation with a maxillary obturator prosthesis in individuals with palatal resection. Although speech outcome data exist in the literature for such patients, relatively few reports have used clinical tools designed to measure the acoustic, physiologic, and perceptual bases of speech. This investigation reports these measures for individuals rehabilitated with a maxillary obturator.

MATERIALS AND METHODS: Speech measurements were collected prospectively at three clinical visit times (preoperative, postresection without an obturator, and with a definitive obturator) for 12 patients assigned to three groups based on the extent of their resection (< half the hard palate, > or = half the hard palate, hard and soft palates). Acoustic data were obtained with the Nasometer, aeromechanical data were collected with the PERCI-SARS, and perceptual ratings of speech intelligibility were obtained through listener analysis.

RESULTS: Significant differences existed among the three treatments for all dependent variables and revealed that speech without an obturator is significantly different from the preoperative state, while speech with an obturator does not differ significantly from preoperative function. Individuals with soft palate involvement exhibited significantly poorer nasalance values than individuals with involvement of the hard palate only.

CONCLUSION: Rehabilitation with a maxillary obturator is successful in restoring preoperative speech function. Rehabilitation of individuals with involvement of the soft palate may be more challenging.

In this study, Kay’s Nasometer was used to obtain nasalance values from the acoustic data collected.

“Cepstral Peak Prominence: A more reliable measure of dysphonia,” Heman-Ackah, Yolanda D., Reinhardt J. Heuer, Deirdre D. Michael, Rosemary Ostrowski, Michelle Horman, Margaret M. Baroody, James Hillenbrand, and Robert T. Sataloff, Annals of Otology, Rhinology & Laryngology, Vol. 112, Number 4, pp. 324-333, April 2003.

Quantification of perceptual voice characteristics allows the assessment of voice changes. Acoustic measures of jitter, shimmer, and noise-to-harmonic ratio (NHR) are often unreliable. Measures of cepstral peak prominence (CPP) may be more reliable predictors of dysphonia. Trained listeners analyzed voice samples from 281 patients. The NHR, amplitude perturbation quotient, smoothed pitch perturbation quotient, percent jitter, and CPP were obtained from sustained vowel phonation, and the CPP was obtained from running speech. For the first time, normal and abnormal values of CPP were defined, and they were compared with other acoustic measures used to predict dysphonia. The CPP for running speech is a good predictor and a more reliable measure of dysphonia than are acoustic measures of jitter, shimmer, and NHR.

Kay’s CSL, Model 4300B, was used to digitize the voice samples collected in this study. Acoustic analysis was performed using Kay’s MDVP to obtain measures of jitter, shimmer, and noise-to-harmonic ratio.

“Comparison of voice characteristics following three different methods of treatment for laryngeal cancer,” Eksteen, Eddie C., Jana Rieger, Margaret Nesbitt, and Hadi Seikaly, Journal of Otolaryngology, Vol. 32, Number 4, pp. 250-253, March 2003.

Introduction: Laryngeal cancer treatment has become more complex and diversified in past decades. Many different methods of treatment have evolved, and most have been able to restore the patient’s function and maintain some form of functional speech. This study was designed to evaluate the voice and speech characteristics of patients who have undergone different treatments for laryngeal cancer and to compare those characteristics with those of age- and sex-matched normal laryngeal speakers.

Methods: Twenty-two male subjects participated in the study. Five men were treated with radiation therapy, 6 men had supracricoid partial laryngectomy, 6 men had undergone total laryngectomy with tracheoesophageal puncture, and 5 men were normal laryngeal speakers. Acoustic, acromechanical, and perceptual assessments of speech were collected.

Results: Significant age effects were found for maximum phonation times. As age increased, maximum phonation time decreased (p < .005). Significant differences were found between groups for the following dependent variables: percentage of voiceless phonation, maximum phonation time, laryngeal airway resistance, subglottal pressure, oral flow, and word intelligibility. Trends in the data for differences between groups were noted for the following acoustic variables: noise-to-harmonics ratio, jitter, and shimmer.

Conclusions: All patients developed or maintained a source of voicing after treatment and could use speech functionally, as demonstrated by normal sentence intelligibility. The radiation treatment group had voices that differed the least from the control group, whereas the opposite was true for the surgical groups, especially for those with total laryngectomy.

In this study, Kay’s Multi-Dimensional Voice Program (MDVP) in conjunction with the CSL, Model 4400, was used to perform the acoustic analysis, specifically measures of fundamental frequency, noise-to-harmonic ratio, jitter, shimmer, and percentage of voiceless phonation on speech samples of the sustained vowel/ah/; fundamental frequency was obtained for connected speech samples.

“Vocal Dose Measures: Quantifying Accumulated Vibration Exposure in Vocal Fold Tissues,” Titze, Ingo R., Jan G. Svec, and Peter S. Popolo. JSLHR, Vol. 46, Number 4, pp. 919-932, August 2003.

To measure the exposure to self-induced tissue vibration in speech, three vocal doses were defined and described: distance dose, which accumulates the distance that tissue particles of the vocal folds travel in an oscillatory trajectory; energy dissipation dose, which accumulates the total amount of heat dissipated over a unit volume of vocal fold tissues; and time dose, which accumulates the total phonation time. These doses were compared to a previously used vocal dose measure, the vocal loading index, which accumulates the number of vibration cycles of the vocal folds. Empirical rules for viscosity and vocal fold deformation were used to calculate all the doses from the fundamental frequency (F0) and sound pressure level (SPL) values of speech. Six participants were asked to read in normal, monotone, and exaggerated speech and the doses associated with these vocalizations were calculated. The results showed that large F0 and SPL variations in speech affected the dose measures, suggesting that accumulation of phonation time alone is insufficient. The vibration exposure of the vocal folds in normal speech was related to the industrial limits for hand-transmitted vibration, in which the safe distance dose was derived to be about 500 m. This limit was found rather low for vocalization; it was related to a comparable time dose of about 17 min of continuous vocalization, or about 35 min of continuous reading with normal breathing and unvoiced segments. The voicing pauses in normal speech and dialogue effectively prolong ht e safe time dose. The derived safety limits for vocalization will likely require refinement based on a more detailed knowledge of the differences in hand and vocal fold tissue morphology and their response to vibrational stress, and on the effect of recovery of the vocal fold tissue during voicing pauses.

In this study, Kay’s Computerized Speech Lab (CSL), Model 4400, was used in conjunction with a DAT recorder and direct DAT interface for multi-channel data acquisition (both acoustic and EGG data) and storage.

“Perceptual Evaluation of Tracheoesophageal Speech by Naive and Experienced Judges Through the Use of Semantic Differential Scales,” Van As, Corina,  Florien J. Koopmans-van Beinum, Louis C.W. Pols, and Frans J.M. Hilgers, JSLHR, Vol. 46, Number 4, pp. 947-959, August 2003.

The present study was conducted to investigate voice quality in tracheoesophageal speech by means of perceptual evaluations and to develop a clinically useful subset of perceptual scales sufficient for these perceptual evaluations. The perceptual ratings were obtained from both naïve and trained raters (speech-language pathologists [SLPs] after listening to a read-aloud text. The perceptual evaluations were performed by means of 19 semantic dipolar 7-point scales for the naïve raters and 20 semantic bipolar 7-point scales for the trained raters. The trained raters were also asked to judge the overall voice quality as good, reasonable, or poor. Both naïve listeners and trained SLPs were able to perform reliable perceptual judgments. Naïve raters judged the tracheoesophageal voice as more deviant than the trained raters did. Naïve raters made judgments based on 2 underlying perceptual dimensions (voice quality and pitch), whereas the trained raters made judgments based on 4 underlying perceptual dimensions (voice quality, tonicity, pitch, and tempo). These perceptual dimensions were further subdivided into a subset of 4 perceptual scales for the naïve raters and a subset of 8 perceptual scales for the trained raters. This appeared to provide a sufficient coverage of the underlying perceptual dimensions used by the listeners.

The authors used Kay’s Computerized Speech Lab (CSL), Model 4300B (in conjunction with a DAT) for recording the tracheoesophageal speech samples which were evaluated perceptually in this study.

“Changes in the Human Vocal Tract Due to Aging and the Acoustic Correlates of Speech Production: A Pilot Study,” An Xue, Steve and Grace Jianping Hao, JSLHR, Vol. 46, Number 3, pp. 689-701, June 2003.

This investigation used a derivation of acoustic reflection (AR) technology to make cross-sectional measurements of changes due to aging in the oral and pharyngeal lumina of male and female speakers. The purpose of the study was to establish preliminary normative data for such changes due to aging in the formant frequencies of selected spoken vowels and their long-term average spectra (LTAS) analysis. Thirty-eight young men and women and 38 elderly men and women were involved in the study. The oral and pharyngeal lumina of the participants were measured with AT technology, and their formant frequencies were analyzed using the Kay Elemetrics Computerized Speech Lab. The findings have delineated specific and similar patterns of aging changes in human vocal tract configurations in speakers of both genders. Namely the oral cavity length and volume of elderly speakers increased significantly compared to their young cohorts. The total vocal tract volume of elderly speakers also showed a significant increment, whereas the total vocal tract length of elderly speakers did not differ significantly from their young cohorts. Elderly speakers of both genders also showed similar patterns of acoustic changes of speech production, that is, consistent lowering of formant frequencies (especially F1) across selected vowel productions. Although new research models are still needed to succinctly account for the speech acoustic changes of the elderly, especially for their specific patterns of human vocal tract dimensional changes, this study has innovatively applied the noninvasive and cost-effective AR technology to monitor age-related human oral and pharyngeal lumina changes that have direct consequences for speech production.

Kay’s Computerized Speech Lab (CSL), Model 4300B, was used for analysis of formant frequencies of the word tokens produced by the study’s participants.

“Voice, Speech, and Swallowing Outcomes in Laser-Treated Laryngeal Cancer,” Jepsen, Matthew C., Deepak Gurushanthaiah, Nelson Roy, Marshall E. Smith, Steven D. Gray, and R. Kim Davis, Laryngoscope, Vol. 113, Number 6, pp. 923-928, June 2003.

To describe preliminary voice, speech, and swallowing outcomes in patients treated by endoscopic laser excision of laryngeal cancer with or without adjuvant radiation therapy. Study Design: Retrospective review. Methods: Seventeen surgically treated patients (five T2 glottic and 12 clinically staged T2 supraglottic squamous cell carcinomas) participated in the study. Self-ratings of voice (Voice Handicap Index) and swallowing (M.D. Anderson Dysphagia Inventory) were completed, as well as independent auditory-perceptual ratings of voice and speech recordings. Results: Although no significant difference between Voice Handicap Index, M.D. Anderson Dysphagia Inventory, and listener ratings was identified based on tumor site and irradiation status, there was a trend toward poorer outcomes in patients who received adjuvant radiation therapy. Whereas the patients having supraglottic cancer tended to report better voice but poorer swallowing outcomes, the glottic cancer group displayed the opposite pattern. Severity on Voice Handicap Index correlated significantly with listener severity ratings of speech, suggesting that the patients’ perception of their voice handicap was similar to the listeners’ judgments of their speech severity. Conclusions: The results suggest the following trends: 1) Adjuvant radiation therapy was associated with poorer outcomes for voice, speech, and swallowing and may be associated with more impairment than surgery alone and 2) poorer outcomes on voice and swallowing were observed for the glottic and supraglottic cancer groups, respectively. To bolster these preliminary finds, additional outcomes studies in patients treated with conservation therapy are needed.

“Acoustic Analysis of Pathological Voices Compressed with MPEG System,” Gonzalez, Julio, Teresa Cervera, and M. Jose Llau, Journal of Voice, Vol. 17, Number 2, pp. 126-139, June 2003.

The MPEG-1 Layer 3 compression schema of audio signal, commonly known as mp3, has caused a great impact in recent years as it has reached high compression rates while conserving a high sound quality. Music and speech samples compressed at high bitrates are perceptually indistinguishable from the original samples, but very little was known about how compression acoustically affects the voice signal. A previous work with normal voices showed a high fidelity of high-bitrate compressions both in voice parameters and the amplitude-frequency spectrum. In the present work, dysphonic voices were tested through two studies. In the first study, spectrograms, long-term average spectra (LTAS), and fast Fourier transform (FFT) spectra of compressed and original samples of running speech were compared. In the second study, intensities, formant frequencies, formant bandwidths, and a multidimensional set of voice parameters were tested in a set of sustained phonations. Results showed that compression of high bitrates (96 and 128 kbps) preserved the relevant acoustic properties of the pathological voices. With compressions at lower bitrates, fidelity decreases, introducing some important alterations. Results from both works, Gonzalez and Cervera and this paper, open up the possibility of using MPEG-compression at high bitrates to store or transmit high-quality speech recordings, without altering their acoustic properties.

In this study, voice samples from Kay’s Disordered Voice Database were used; in addition, Kay’s Multi-Dimensional Voice Program was used to compare ten voice parameters (across original versus compressed speech samples) including Fo, Jitter, Shimmer, Relative Average Perturbation, Amplitude Perturbation Quotient, Noise to Harmonic Ratio, Voice Turbulence Index, Soft Phonation Index, Number of Subharmonic Segments, and Number of Unvoiced Segments.

“Vibrato Rate Adjustment,” Dromey, Christopher, Neisha Carter, and Arden Hopkin, Journal of Voice, Vol. 17, Number 2, pp. 168-178, June 2003.

The goal of the present study was to document the acoustic changes that occur as singers attempt to increase or decrease their vibrato rate to match target stimuli. Eight advanced singing students produced vowels with vibrato in three registers, both naturally and while attempting to match faster or slower rate stimuli. Slower rates were associated with lower intensity and less steady vibrato. Faster rates involved increased vibrato extent in the chest register and increased intensity in the head register. Singers whose spontaneous vibrato rates ere naturally either slower or faster tended to also be relatively slower or faster when matching target rates. This ability to modify rate may have beneficial effects on the artistic quality of the voice for performance.

In this study, Kay’s Computerized Speech Lab (CSL), Model 4300B was used to digitize the acoustic signals; Kay’s Motor Speech Profile (MSP) was subsequently used to analyze each singer’s vibrato.

“Pitch Matching Accuracy of Trained Singers, Untrained Subjects with Talented Singing Voices, and Untrained Subjects with Nontalented Singing Voices in Conditions of Varying Feedback,” Watts, Christopher, Jessica Murphy, and Kathryn Barnes-Burroughs, Journal of Voice, Vol. 17, Number 2, pp. 185-194, June 2003.

At a physiological level, the act of singing involves control and coordination of several systems involved in the production of sound, including respiration, phonation, resonance, and afferent systems used to monitor production. The ability to produce a melodious singing voice (e.g. in tune with accurate pitch) is dependent on control over those motor and sensory systems. To test this position, trained singers and untrained subjects with and without expressed singing talent were asked to match pitches of target pure tones. The ability to match pitch reflected the ability to accurately integrate sensory perception wit motor planning and execution. Pitch matching accuracy was measured at the onset of phonation (prephonatory set) before external feedback could be utilized to adjust the voiced source, during phonation when external auditory feedback could be utilized and during phonation when external auditory feedback was masked. Results revealed trained singers and untrained subjects with singing talent were no different in their pitch-matching abilities when measured before or after external feedback could be utilized. The untrained subjects with singing talent were also significantly more accurate than the trained singers when external auditory feedback was masked. Both groups were significantly more accurate than the untrained subjects without singing talent.

Kay’s Computerized Speech Lab (CSL) was used for signal generation and signal acquisition in this study. Kay’s Voice Range Profile software was used to measure each participant’s fundamental frequency range.

“Effect of Hydration and Vocal Rest on the Vocal Fatigue in Amateur Karaoke Singers,” Yiu, Edwin M-L and Rainy MM Chan, Journal of Voice, Vol. 17, Number 2, pp. 216-227, June 2003.

Karaoke singing is a very popular entertainment among young people in Asia. It is a leisure singing activity with the singer’s voice amplified with special acoustic effects in the backdrop of music. Music video and song captions are shown on television screen to remind the singers during singing. It is not uncommon to find participants singing continuously for four to five hours each time. As most of the karaoke singers have no formal training in singing, these amateur singers are more vulnerable to developing voice problems under these intensive singing activities. This study reports the performance of 20 young amateur singers (10 males and 10 females, aged between 20-25 years) on a series of phonatory function tasks carried out during continuous karaoke singing. Half of the singers were given water to drink and short duration of vocal rests at regular intervals during singing and the other half sang continuously without taking any water or rest. The subjects who were given hydration and vocal rests sang significantly longer than those who did not take any water or rest. The voice quality, as measured by perceptual and acoustic measures, and vocal function, as measured by phonetogram, did not show any significant changes during singing in the subjects who were given water and rest during the singing. However, subjects who sang continuously without drinking water and taking rests showed significant changes in the jitter measure and the highest pitch they could produce during singing. These results suggest that hydration and vocal rests are useful strategies to preserve voice function and quality during karaoke singing. This information is useful educational information for karaoke singers.

Kay’s Multi-Dimensional Voice Program (MDVP) was used in conjunction with the Computerized Speech Lab (CSL) for voice assessment, specifically to obtain mean fundamental frequency, jitter (percent), shimmer (dB), and noise-to-harmonic ratios.

“Instrumental and Perceptual Evaluations of Two Related Singers, Buder,” Eugene, H. and Teresa Wolf, Journal of Voice, Vol. 17, Number 2, pp. 228-244, June 2003.

The primary goal of this study was to characterize a performer’s singing and speaking voice. One woman was not admitted to a premier choral group, but her sister, who was comparable in physical characteristics and background, was admitted and provided a valuable control subject. The perceptual judgment of a vocal coach who conducted the group’s auditions was decisive in discriminating these 2 singers. The singer not admitted to the group described a history of voice pathology, lacked a functional head register, and spoke with a voice characterized by hoarseness. Multiple listener judgments and acoustic and aerodynamic evaluations of both singers provided a more systematic basis for determining: 1) the phonatory basis for this judgment; 2) whether similar judgments would be made by groups of vocal coaches and speech-language pathologists; and 3) whether the type of tasks (e.g., sung vs. spoken) would influence these judgments. Statistically significant differences were observed between the ratings of vocal health provided by two different groups of listeners. Significant interactions were also observed as a function of the types of voice samples heard by these listeners. Instrumental analyses provided evidence that, in comparison to her sister, the rejected singer had a compromised vocal range, glottal insufficiencies as assessed aerodynamically and electroglottographically, and impaired acoustic quality, especially in her speaking voice.

In this study, Kay’s Computerized Speech Lab (CSL), Model 4300B, was used to acquire voice samples; Kay’s Voice Range Profile (VRP), Model 4326; CSL Pitch Program, Model 4331; Multi-Dimensional Voice Program (MDVP), Model 4305; Electroglottograph (EGG), Model 4338; and Aerophone II, Model 6800, were used to noninvasively evaluate various vocal functions.

“En Route to the Three-Dimensional Registration and Analysis of Speech Movements: Instrumental Techniques for the Study of Articulatory Kinematics,” Earnest, Margaret M. and Ludo Max, Contemporary Issues in Communication Science and Disorders, Vol. 30, pp. 5-25, Spring 2003.

Increasing our understanding of the physiological processes underlying speech production is crucial for both theoretical and clinical reasons. Such gains in theory and clinical application, however, depend on the availability and use of technologically advanced instruments that can accurately reveal the processes of interest. Consequently, it is essential that not only researchers but also clinicians and students in communication sciences and disorders have access to up-to-date information about the most recent developments in the area of instrumental analyses of speech production. Those professionals involved in research continually need to make important decisions regarding the most appropriate instruments to address their specific research questions, whereas those in clinical practice need at least a basic understanding of the same information to interpret the contemporary literature and to decide when a specific instrument is ready to be used for diagnosis or treatment. Therefore, it is unfortunate that, despite numerous rapid and exciting advances in analog and digital technology, instrumental speech analysis procedures receive relatively little attention in most speech-language pathology students’ academic curriculum. Hence, the purpose of this paper is to provide a summary of this important information by presenting an overview of various instrumental techniques that are being used in several laboratories or that are currently in an advanced stage of development. To limit the scope of this work, only instruments suitable for the transduction of articulatory movements are presented. Specific applications, capabilities, and limitations of each of the systems are discussed.

In this overview of well-established instrumental techniques, Kay’s Palatometer was cited as one of the most commonly used systems for electropalatography.

“A Preliminary Study of Speech Rates in Young Australian English-Speaking Children,” Robb, Michael, Harvey Gilbert, Ricki Reed, and Amanda Bisson, Contemporary Issues in Communication Science and Disorders, Vol. 30, pp. 84-91, Spring 2003.

Speaking rate and articulation rate data are provided for a group of 10 Australian children (aged 30-51 months). Articulation rates were significantly faster than overall speaking rates. Speaking rate and articulation rate were positively correlated with utterances up to seven syllables in length. The results are compared to previous data obtained for older Australian children, as well as data obtained for same-aged American English-speaking children. The clinical applicability of the present data is discussed.

Kay’s Computerized Speech Lab (CSL), Model 4300B, was used for the acoustic analysis of each child’s individual utterances in this study.

“Laryngeal Effects Of Antigen Stimulation Challenge with Perennial Allergen Dermatophagoides Pteronyssinus,” Reidy, Patrick M., James P. Dworkin, and John H. Krouse, Otolaryngology-Head and Neck Surgery, Vol. 128, Number 4, pp. 455-462, April 2003.

OBJECTIVE: We conducted a pilot study to assess the effects of antigen stimulation on the appearance and function of the larynx.

STUDY DESIGN AND SUBJECTS: The prospective, double-blind, randomized study included 9 adult patients with a skin-prick test positive for Dermatophagoides pteronyssinus.

MAIN OUTCOME MEASURES: Subjects were blindly challenged via nebulizer with either an active antigenic suspension or placebo. Baseline and 30-minute evaluations of the larynx were performed. Assessments included subjective voice and videostroboscopic assessments, acoustic analysis of voice, speech aerodynamic testing, and allergy and voice handicap questionnaires.

RESULTS: Although both inflammation and increased mucus were noted, there were no significant differences between the antigen- and placebo-exposed subjects on any of the measures obtained.

CONCLUSIONS: Our preliminary investigation was not successful in demonstrating a direct causal relationship between antigen exposure and physical or functional changes in the larynx. Future studies will involve modifications to our current methodology, including increasing the concentration of antigen, prolonging the exposure time, and observing for late phase responses.

In this study, laryngeal anatomy and physiology were analyzed using Kay’s RLS, Model 9100. Kay’s CSL, Model 4300, was used for acoustic analysis, specifically to measure jitter, shimmer, Fo, and harmonic-to-noise ratio. The Aerophone was used to obtain the aerodynamic measurements of mean transglottic airflow, glottal resistance, and subglottal pressure.

“An Alternative Surgical Procedure for the Treatment of Vocal Fold Retention Cyst,” Chang, Hsin-Pin and Shyue-Yih Chang, Otolaryngology-Head and Neck Surgery, Vol. 128, Number 4, pp. 470-477, April 2003.

OBJECTIVE: Enucleation is the standard surgical procedure for vocal fold retention cyst, but it is sometimes technically challenging when the cyst is large. A simple alternative procedure, which evolved from the concept of marsupialization of cystic lesions, is presented, and the treatment results are reported.

METHODS: Termed the “wide-opening method,” this technique involves the removal of the medial half of the cyst with its overlying mucosa, which creates a large opening that prevents content retention. Twenty-one consecutive patients with a cyst with a diameter of greater than 2 mm were treated by this method. Videostroboscopy and voice function assessments were performed preoperatively and postoperatively.  

RESULTS: The procedure was completed on all patients without difficulty. Voice function assessments showed statistically significant improvement post-operatively. Videostroboscopy showed improved vocal fold vibration postoperatively in all patients, although in 9 patients the postoperative wound with mild local stiffness was observable. Recurrence was noted in 1 patient.

CONCLUSIONS: The wide-opening method is simple in technique, especially when the cyst is large. Voice improvement can be achieved postoperatively, and the recurrence rate is low.

In this study, Kay’s CSL was used to perform acoustic analysis including jitter (%), shimmer (dB), and HNR. Kay’s Aerophone II was used for aerodynamic measurements, while the Voice Range Profile (VRP) was used to obtain pitch range and intensity range.

“Vocal Outcome After Endoscopic Cordectomies for TIS and T1 Glottic Carcinomas,” Peretti, Giorgio, Cesare Piazza, Giovanna Cantarella, Cristiano Balzanelli, and Piero Nicolai, Annals of Otology, Rhinology & Laryngology, Vol. 112, Number 2, pp. 174-179, February 2003.

A cohort of 101 patients with previously untreated glottic cancer (15 Tis, 66 T1a, and 20 T1b) who underwent endoscopic CO2 laser excision between January 1995 and December 1997 was prospectively analyzed. The depth and extension of the excision were graded according to the European Laryngological Society Classification including 5 types of cordectomy. All patients were subsequently examined every 2 months for a period ranging from 30 to 66 months (mean, 48 months). The rates of 5-year overall survival, disease-free survival, ultimate local control with laser alone, and laryngeal preservation were 85%, 87%, 93%, and 95%, respectively. Sixty-nine patients underwent, at least 1 year after surgery, videolaryngostroboscopy combined with perceptual and objective evaluation of the voice, and spirometry. Acoustic parameters were compared with those obtained in a matched control group by Kruskal-Wallis test. No statistically significant difference was found (p> .05) between patients submitted to subepithelial (type I) and subligamental (type II) cordectomies and controls.

Kay’s 70-degree rigid endoscope and Digital Strobe, Model 9200, were used to perform the videolaryngostroboscopic examinations in this study. The Multi-Dimensional Voice Program (MDVP), in conjunction with the CSL, Model 4300B, was used for voice assessment, specifically to obtain objective measures of fundamental frequency, jitter, shimmer, and noise-to-harmonic ratio.

“Mid-Basal-to-Ceiling Versus Mid-Ceiling-to-Basal Elicitation of Maximum Phonational Frequency Range,” Zraick, Richard I., Mary P. Keyes, James C. Montague, and J. Hope Keiser, Journal of Voice, Vol. 16, Number 3, pp. 317-322, September 2002.

The purpose of this study was to investigate if there was an effect of task on the determination of maximum phonational frequency range (MPFR). Two tasks commonly used to elicit MPFR in clinical voice evaluations were compared. Normal adult females (n = 30) were examined. No statistically significant effect of task was found. Both tasks (mid-basal-to-ceiling and mid-ceiling-to-basal) were found to have a high positive correlation (0.89). Implications of the use on one task to determine maximum phonational frequency range are discussed, as is the possibility of a task effect on determination of other voice parameters.

The Voice Quality Assessment module of the Visi-Pitch II was used to obtain the quantitative acoustic measurements (i.e., max Fo, min Fo, MPFR: hertz; MPFR: semitones) reported in this study.

“Spectral Changes Due to Performance Environment in Singers, Nonsingers, and Actors,” Rothman, Howard B., W.S. Brown, Jr., and J. Ronald LaFond, Journal of Voice, Vol. 16, Number 3, pp. 323-332, September 2002.

From postrecording interviews of professional singers, it was hypothesized that recording environments, i.e., sound-treated environment versus an auditorium, may induce different vocal behaviors. To test this hypothesis, three groups consisting of nonsingers, singers, and actors were recorded in two different recording environments: a sound-treated booth (IAC) and an auditorium (AUD). Three recordings were obtained from each participant: recording one (IAC) and two (AUD1) required the participants to read in a normal voice; recording three (AUD2) required participants to pretend that they were “performing” before a full house. Results indicated that only the singers and the actors exhibited significant spectral and/or frequency/duration differences from one recording environment to another, with the most dramatic differences exhibited by the singers. It was concluded that the environment in which we record experimental samples from professional voice users, especially singers, should be considered as a variable that can affect results.

Frequency measures in this study were obtained using the Multi-Dimensional Voice Program (MDVP); duration and spectral measures were obtained with the FFT spectrum analysis option in the CSL.

“Poor Voice Quality in Future Elite Vocal Performers and Professional Voice Users,” Timmermans, B., M.S. De Bodt, F.L. Wuyts, A. Boudewijns, G. Clement, A. Peeters, and P.H. Van de Heyning, Journal of Voice, Vol. 16, Number 3, pp. 372-382, September 2002.

The voice quality of 86 occupational voice users, i.e., students of a high school for audiovisual communication, was assessed by means of a multi-dimensional test battery containing: the GRBAS scale, videolaryngostroboscopy, maximum phonation time, jitter, lowest intensity, highest frequency, dysphonia severity index (DSI), and voice handicap index (VHI). In a questionnaire on daily habits the prevalence of smoking, eating habits, and vocal abuse were recorded. A comparison of the voice characteristics of the future occupational voice users with a control group revealed significant differences. The results of the VHI and the DSI of these students revealed significantly worse scores than the score of a control group characterized by no vocal complaints. Moreover, the questionnaire on daily habits showed that the future elite vocal performers and professional voice users take less precaution for the care of their voices. These findings support the importance of a good balanced vocal coaching.

In this study, the Multi-Dimensional Voice Program (MDVP), Model 4305, was used for acoustic analysis, specifically jitter (%); the CSL was used to analyze fundamental frequency.

“Nasalance Changes After Functional Endoscopic Sinus Surgery,” Soneghet, Renata, Rodrigo Paula Santos, Mara Behlau, Walter Habermann, Gerhard Friedrich, and Heinz Stammberger, Journal of Voice, Vol. 16, Number 3, pp. 392-397, September 2002.

Forty adult patients diagnosed with chronic rhinosinusitis who underwent functional endoscopic sinus surgery (FESS), were analyzed with respect to postoperative resonatory voice changes. For evaluation the patients were asked about their subjective impression of voice changes using a questionnaire. An objective assessment was performed by determining the so-called nasalance using the Nasometer (Kay Elemetrics), preoperatively, on the immediate postoperative follow-up (2 days after surgery), and approximately 1 month after surgery. The mean nasalance values increased significantly one month after FESS whereas the immediate postoperative control (2 days after surgery) showed a decrease of nasalance. Although FESS is a minimally invasive procedure, it can change the acoustic characteristics of the vocal tract in the long term and produce a significant increase in nasality. The authors strongly recommend that clinicians inform all patients, in particular voice professionals, about the possible effects of endonasal sinus surgery on voice quality.

The Nasometer was used to assess nasalance at three different stages of this study: preoperatively, 2 days postoperatively, and 1 month postoperatively.

“Voice and Treatment Outcome from Phonosurgical Management of Early Glottic Cancer,” Zeitels, Steven M., Robert E. Hillman, Ramon A. Franco, and Glenn W. Bunting, Annals of Otolaryngology, Vol. 111, Number 12, Supplement 190, pp. 3-20, December 2002.

Phonosurgical management of early glottic cancer has evolved considerably, but objective vocal outcome data are sparse. A prospective clinical trial was done on 32 patients with unilateral cancer (T1a in 28 and T2a in 4) who underwent ultranarrow-margin resection; 15 had resection superficial to the vocal ligament, and 17 deep to it. The subepithelial infusion technique facilitated selection of these patients for the appropriate procedure. All are cancer-free without radiotherapy or open surgery. Involvement of the anterior commissure (22/32) or the vocal process (15/32) of the arytenoid cartilage did not influence local control. Nine of 17 patients had resection of paraglottic musculature, and all underwent medialization reconstruction by lipoinjection and/or Gore-Tex laryngoplasty. Eight of the 17 had resections deep to the vocal ligament, but without vocalis muscle, and 1 of the 8 underwent medialization. Posttreatment vocal function measures were obtained for all patients. A clear majority of the patients displayed normal values for average fundamental frequency (72%) during connected speech, and normal noise-to-harmonic ratio (75%) and average glottal airflow (91%) measures during sustained vowels. Smaller majorities of patients displayed normal values for average sound pressure level (SPL: 59%) during connected speech and for maximum ranges for fundamental frequency (56%) and SPL (59%). Fewer than half of the patients displayed normal values for sustained vowel measures of jitter (45%), shimmer (22%), and maximum phonation time (34%). Almost all patients had elevated subglottal pressures and reduced values for the ratio of SPL to subglottal pressure (vocal efficiency). There were significant improvements in a majority of patients for most vocal function measures after medialization reconstruction. Normal or near-normal conversation-level voices were achieved in most cases, regardless of the disease depth, by utilization of a spectrum of resection and reconstruction options. These favorable results are based on establishing aerodynamic glottal competency and preserving the layered microstructure of noncancerous glottal tissue.

In this study, CSL was used for acoustic analysis, Aerophone II for aerodynamic measurements, and the Computer-Integrated  RLS Strobscopy System for laryngeal imaging and functional assessment.

“Phonomicrosurgery in Singers and Performing Artists: Treatment Outcomes, Management Theories, and Future Directions,” Zeitels, Steven M., Robert E. Hillman, Rosemary Desloge, Marcello Mauri, and Patricia B. Doyle, Annals of Otolaryngology, Vol. 111, Number 12, Supplement 190, pp. 21-40, December 2002.

Phonomicrosurgery in performing artists has historically been approached with great trepidation, and vocal outcome data are sparse. The vocal liability of surgically disturbing the superficial lamina propria (SLP) and epithelium must be balanced with the inherent detrimental vocal effect of the lesion(s). A prospective investigation was performed on 185 performing artists who underwent phonomicrosurgical resection of 365 lesions: 201 nodules, 71 polyps, 66 varices and ectasias, 13 cysts, 8 keratotic lesions, 2 granulomas, 2 Reinke’s edema, and 2 papillomas. Nearly all patients with SLP lesions reported improvement in their postsurgical vocal function. This subjective result was supported by objective acoustic analysis and aerodynamic measures. All postsurgical objective vocal function measures fell within normal limits, including a few that displayed presurgical abnormalities. However, given the relative insensitivity of standard objective measures to assess higher-level vocal performance-related factors, it is even more noteworthy that 8 of 24 objective measures displayed statistically significant postsurgical improvements in vocal function. Such changes in objective measures mostly reflect overall enhancement in the efficiency of voice production. Phonomicrosurgical resection of vocal fold lesions in performing artists is enjoying an expanding role because of a variety of improvements in diagnostic assessment, surgical instrumentation and techniques, and specialized rehabilitation. Most of the lesions are the result of phonotrauma and arise within the SLP. Successful management depends on prudent patient selection and counseling, ultraprecise technique, and vigorous vocal rehabilitation. Furthermore, an understanding of the vocal function and dysfunction of this high-performance population provides all otolaryngologists who manage laryngeal problems with valuable information that they can extrapolate for use in their practices.

The authors used CSL, Electroglottograph, Aerophone II, and Computer-Integrated RLS Stroboscopy System for objective instrumental assessment pre- and post-surgery in this study. 

“Electroglottographic Evaluation of Gender and Vowel Effects During Modal and Vocal Fry Phonation,” Chen, Yang, Michael P. Robb, and Harvey R. Gilbert, Journal of Speech, Language, and Hearing Research, Vol. 45, pp. 821-829, October 2002.

Two unique characteristics of vocal fry register are the occurrence of multiple opening and closing phases occurring within one vibratory cycle and a similar vocal fundamental frequency (Fo) between women and men. The present study tested the hypothesis that significant differences in glottal symmetry exist between women and men during modal phonation, with no significant differences during vocal fry phonation. Consistent with previous studies of modal phonation, it was also hypothesized that a vowel effect would be apparent during vocal fry phonation. Five women and 5 men sustained modal and vocal fry phonations in four vowel contexts (a, ae, u, i). Vocal Fo, duration of opening and closing phase, and contact symmetry (speed quotient) were derived from the electroglottographic (EGG) waveforms. Both female and male speakers demonstrated significantly higher SQ values in vocal fry register than in their modal register, indicating a longer opening phase duration per glottal cycle. Women demonstrated a significantly greater increase in SQ during vocal fry phonations than men, indicating greater asymmetry between opening and closing durations. The results confirmed that gender differences in vocal fold contact behavior not only exist during modal register but also during vocal fry register. No vowel effects on vocal fold contact behavior as inferred using the SQ measure were found for either modal or vocal fry registers. Possible contributing factors to multiple opening and closing phases occurring within a vibratory cycle are discussed.

The Computerized Speech Lab (CSL), Model 4300B, was used for data acquisition and measurement in this study; the Laryngograph was used for obtaining the electroglottographic ( EGG) waveforms.   

“The Influence of Pitch and Loudness Changes on the Acoustics of Vocal Tremor,” Dromey, Christopher, Paul Warrick, and Jonathan Irish, Journal of Speech, Language, and Hearing Research, Vol. 45, pp. 879-890, October 2002.

The effect of tremor on phonation is to modulate an otherwise steady sound source in its amplitude, fundamental frequency, or both. The severity of untreated vocal tremor has been reported to change under certain conditions that may be related to muscle tension. In order to better understand the phenomenon of vocal tremor, its acoustic properties were examined as individuals volitionally altered their pitch and loudness. These voice conditions were anticipated to alter the tension of the intrinsic laryngeal muscles. The voices of 10 individuals with a diagnosis of voice tremor were recorded before participating in a longitudinal treatment study. They produced vowels at low and high pitch and loudness levels as well as in a comfortable voice condition. Acoustic analysis quantified the amplitude and frequency modulations of the speakers’ voices across the various conditions. Individual speakers varied in the way the pitch and loudness changes affected their tremor, but the following statistically significant effects for the speakers as a group were observed: Higher pitch phonation was associated with a more rapid rate for both amplitude and frequency modulations. Amplitude modulation became faster for louder phonation. Low-pitched phonation led to decreases in the extent of amplitude tremor. Varying pitch led to dramatic changes in the phase relationship between amplitude and frequency modulation in some of the speakers, whereas this effect was not apparent in other speakers.

The Computerized Speech Lab (CSL), Model 4300B, was used for data acquisition; the Multi-Dimensional Voice Program (MDVP) was used for tremor analysis.

“Changes in Speech Production in a Child With a Cochlear Implant: Acoustic and Kinematic Evidence,” Goffman, Lisa, David J. Ertmer, and Christa Erdle, Journal of Speech, Language, and Hearing Research, Vol. 45, pp. 879-890, October 2002.

A method is presented for examining change in motor patterns used to produce linguistic contrasts. In this case study, the method is applied to a child receiving new auditory input following cochlear implantation. This child experienced hearing loss at age 3 years and received a multi-channel cochlear implant at age 7 years. Data collection points occurred both pre- and post-implant and included acoustic and kinematic analysis. Overall, this child’s speech output was transcribed as accurate across the pre- and post-implant periods. Post-implant, with the onset of new auditory experience, acoustic durations showed a predictable maturational change, usually decreasing in duration. Conversely, the spatiotemporal stability of speech movements initially became more variable post-implantation. The auditory perturbations experienced by this child during development led to changes in the physiological underpinnings of speech production, even when speech output was perceived as accurate.

The Computerized Speech Lab (CSL), Model 4300B, was used for acquisition of speech samples and acoustic analysis performed in this study. Acoustic analysis included wideband spectrograms, amplitude and waveform displays to measure durations of initial consonants, consonant-vowel transitions, and vowels. 

“Voice Amplification Versus Vocal Hygiene Instruction for Teachers With Voice Disorders: A Treatment Outcomes Study,” Roy, Nelson, Barbara Weinrich, Steven D. Gray, Kristine Tanner, Sue Walker Toledo, Heather Dove, Kim Corbin-Lewis, and Joseph C. Stemple, Journal of Speech, Language, and Hearing Research, Vol. 45, pp. 625-638, August 2002.

Voice problems are common among schoolteachers. This prospective, randomized clinical trial used patient-based treatment outcomes measures combined with acoustic analysis to evaluate the effectiveness of two treatment programs. Forty-four voice-disordered teachers were randomly assigned to one of three groups: voice amplification using ChatterVox portable amplifier (VA, n=15), vocal hygiene (VH, n=15), and a non-treatment control group (n=14). Before and after a 6-week treatment phase, all teachers completed: (a) the Voice Handicap Index (VHI), an instrument designed to appraise the self-perceived psychological consequences of voice disorders; (b) a voice severity self-rating scale; and (c) an audio recording for later acoustic analysis. Based on pre- and post-treatment comparisons, only the amplification group experienced significant reductions on mean VHI scores (p=.045), voice severity self-ratings (p=.012), and the acoustic measures of percent jitter (p=.031) and shimmer (p=.008). The non-treatment control group reported a significant increase in level of vocal handicap as assessed by the VHI (p=.012). Although most pre- to post-treatment changes were in the desired direction, no significant improvements were observed within the VH group on any of the dependent measures.

Between-group comparisons involving the three possible pairings of the groups revealed a pattern of results to suggest that: (a) compared to the control group, both treatment groups (i.e., VA and VH) experienced significantly more improvement on specific outcomes measures and (b) there were no significant differences between the VA and VH groups to indicate superiority of one treatment over another. Results, however, from a post-treatment questionnaire regarding the perceived benefits of treatment revealed that, compared to the VH group, the VA group reported more clarity of their speaking and singing voice (p=.061), greater ease of voice production (p=.001), and greater compliance with the treatment program (p=.045). These findings clearly support the clinical utility of voice amplification as an alternative for the treatment of voice problems in teachers.

In this study, acoustic samples were digitized using the Computerized Speech Lab (CSL), Model 4300B. Quantitative acoustic analysis (jitter, shimmer and noise-to-harmonic ratio) was performed with the Multi-Dimensional Voice Program (MDVP).

“Coarticulation and Formant Transition Rate in Young Children Who Stutter,” Chang, Soo-Eun, Ralph N. Ohde, and Edward G. Conture, Journal of Speech, Language, and Hearing Research, Vol. 45, pp. 676-688, August 2002.

The purpose of this study was to assess anticipatory coarticulation and second formant (F2) transition rate (FTR) of speech production in young children who stutter (CWS) and who do not stutter (CWNS). A total of 14 CWS and 14 age- and gender-matched CWNS in three age groups (3-, 4-, and 5- year-olds) participated in a picture-naming task that elicited single-word utterances. The initial consonant-vowel (CV) syllables of these utterances, comprising either bilabial [b m] or alveolar [d n s z] consonants and a number of vowels [i I e E Ï u o O AI AU], were used for acoustic analysis. To assess coarticulation and speech movement velocity, the F2 onset frequency and F2 vowel target frequency (for coarticulation) and FTR (for speech movement velocity) were computed for each CV syllable and for each participant. Based on these measures, locus equation statistics of slope, y-intercept, and standard error of estimate as well as the FTR were analyzed. Findings revealed a significant main effect for place of articulation and a significantly larger difference in FTR between the two places of articulation for CWNS than for CWS. Findings suggest that the organization of the FTR production for place of articulation may not be as contrastive or refined in CWS as in CWNS, a subtle difficulty in the speed of speech-language production, which may contribute to the disruption of their speech fluency.

The Computerized Speech Lab (CSL), Model 4300B, was used for acoustic analysis performed in this study.

“Laryngeal Collagen Injection as an Adjunct to Medialization Laryngoplasty,” Hoffman, Henry, Daniel McCabe, Timothy McCulloch, Sung M. Jin, and Michael Karnell, Laryngoscope, Vol. 112, pp. 1407-1413, August 2002.

OBJECTIVES/HYPOTHESIS: Dysphonia associated with laryngeal paralysis may be identified in the short term postoperatively or may develop years after successful medialization laryngoplasty. In selected cases, laryngeal collagen injection permits further medialization of one or both vocal folds by small increments to improve phonation after medialization thyroplasty. The study seeks to determine whether collagen injections result in measurable improvements in voice quality and vocal function when offered to select patients who have received medialization thyroplasty.

STUDY DESIGN:  Retrospective review of patient charts and voice database.

METHODS:  Seven patients were treated with Zyderm II collagen using indirect mirror laryngoscopy with a curved injection apparatus. Changes in voice quality and function were assessed by comparing measures obtained before treatment (mean period, 5.6 d), shortly after treatment (mean period, 38.1 d), and in the long term after treatment (mean period, 226 d).

RESULTS: Mean self-ratings of the patient, clinician’s ratings, and objective measures demonstrated measurable improvement in vocal function after collagen injection.

CONCLUSIONS: The office-based procedure offers a simple, efficient adjunct to open techniques of medialization laryngoplasty. Techniques of anesthesia, injection, and patient selection are discussed.

The authors used Kay’s stroboscopy system for vocal fold imaging and the Multi-Dimensional Voice Program (MDVP) for quantitative acoustic measurements reported in the study.

“Acoustic Signature of the Normal Swallow: Characterization by Age, Gender, and Bolus Volume,” Cichero, Julie A. Y. and Bruce E. Murdoch, Annals of Otology, Rhinology, and Laryngology, Vol. 111 (7), pp. 623-632, July 2002.

Despite growing clinical use, cervical auscultation suffers from a lack of research-based data. One of the strongest criticisms of cervical auscultation is that there has been little research to demonstrate how dysphagic swallowing sounds are different from normal swallowing sounds. In order to answer this question, however, one first needs to document the acoustic characteristics of “normal,” non-dysphagic swallowing sounds. This article provides the first normative database of normal swallowing sounds for the adult population. The current investigation documents the acoustic characteristics of normal swallowing sounds for individuals from 18 to more than 60 years of age over a range of thin liquid volumes. Previous research has shown the normal swallow to be a dynamic event. The normal swallow is sensitive to aging  of the oropharyngeal system, and also to the volume of bolus swallowed. The current investigation found that the acoustic signals generated during swallowing were sensitive to an individual’s age and to the volume of the bolus swallowed. There were also some gender-specific differences in the acoustic profile of the swallowing sound. It is anticipated that the results will provide a catalyst for further research into cervical auscultation.

The Computerized Speech Lab (CSL), Model 4300B, was used for digitizing and analyzing the swallowing sounds in this study.

“A Preliminary Report on Micronized AlloDerm Injection Laryngoplasty,” Pearl, Adam W., Peak Woo, Rosemary Ostrowski, Jackie Mojica, David Mandell, and Peter Costantino, Laryngoscope, Vol. 112, pp. 990-996, June 2002.

OBJECTIVES: To report the preliminary data of voice and quality-of-life improvement after micronized AlloDerm injection laryngoplasty in patients with unilateral vocal cord paralysis.

STUDY DESIGN: A prospective study was conducted in patients with unilateral vocal cord paralysis who underwent injection laryngoplasty with micronized AlloDerm.

METHODS: Preoperative and postoperative patient evaluation consisted of videostrobolaryngoscopy, computer voice analysis, airflow, and voice handicap index (VHI) assessment. All injections were conducted with the patient under general anesthesia using the Storz injector system and a 22-gauge spinal needle.

RESULTS: Fourteen patients received injection with an average amount of 0.641 mL. Twelve patients were available for evaluation. Initial results at 4 weeks (n=12) showed significant increase in habitual phonation time from 3.84 to 6.72 seconds (P<.01) and a decrease in airflow from 0.616 to 0.295 L/s (P<.01). The VHI rating improved from 62.8 to 37.5 (P<.01). Jitter and shimmer also improved significantly (P<.05). Stroboscopic findings showed complete closure of glottic gap in 10 patients with excellent return of mucosal wave on the injected side. The mucosal wave return after injection was rapid with little evidence of tissue reaction. Postoperative follow-up at 3 months (n=8) demonstrated slight resorption of the material, but sustained excellent voice was noted in 87.5%. Minimal morbidity and tissue reaction were noted.

CONCLUSIONS: Micronized AlloDerm appears to be a safe new material that is suitable for injection laryngoplasty. Longer results are pending.

The authors used Kay instrumentation for objective assessment of patient performance before and after surgery. The Digital Strobe was used  for stroboscopic imaging. The Computerized Speech Lab (CSL) and the Multi-Dimensional Voice Program (MDVP) were used for acoustic analysis.  Real-Time Pitch (CSL software module) was used  for maximum phonation time assessment.  Aerophone II was used  for aerodynamic analysis.

“Fundamental Frequency Onset and Offset Behavior: A Comparative Study of Children and Adults,” Robb, Michael P. and Allan B. Smith, Journal of Speech, Language, and Hearing Research, Vol. 45, pp. 446-456, June 2002.

Short-term changes in vowel fundamental frequency (Fo) immediately preceding (Fo offset) and following (Fo onset) production of voiceless obstruents were examined in groups of 4-year-olds, 8-year-olds, and 21-year-olds. Definitive patterns of laryngeal behavior were observed for each measure. Fo was found to significantly lower at vowel offset across age groups, with no significant differences noted between groups, suggesting that Fo offset is simply an acoustic consequence of producing a voiceless obstruent preceded by a vowel. The Fo at vowel onset was high and significantly decreased thereafter. Age-related differences were identified for Fo onset with 4-year-olds in that their Fo rose to a lesser degree than that of adults. However, adult females demonstrated a greater change in both Fo onset and Fo offset behavior than adult males and children, suggesting that age-related differences in Fo behavior are likely to be influenced by sex. The results are discussed with regard to the physiologic constraints of Fo surrounding voiceless obstruent production in children and adults.

The Computerized Speech Lab (CSL), Model 4300B, was used for data digitization and analysis done in this study.

“Speaking Slowly: Effects of Four Self-Guided Training Approaches on Adults’ Speech Rate and Naturalness,” Logan, Kenneth J., Rosalyn R. Roberts, Aneesha P. Pretto, and Megan J. Morey, American Journal of Speech-Language Pathology, Vol. 11, pp. 163-174, May 2002.

Speech-language pathologists often ask parents of children who stutter to reduce their conversational pace when talking with their children. Little is known, however, about how best to help parents accomplish this task. Two experiments were conducted to examine this issue. In Experiment 1, adult females altered speech rate via one of four self-guided methods. Post-training speech rates for all four experimental groups (n=8) were significantly slower than those of speakers in a control group. The extent of rate reduction varied significantly across groups, and speakers, rated their resultant speech as unnatural. In Experiment 2, 39 female listeners rated the naturalness of sentences from the five groups in Experiment 1. Naturalness ratings were higher for the Control group than for a group using a self-devised rate-reduction method (SDM). In turn, SDM ratings were higher than those for groups trained to alter articulation rate and intra-sentence pauses. Across groups, the slower a speaker’s post-training speech rate, the less natural listeners judged the speech to sound (r=.95). Results suggest that although none of the methods were clearly superior, adults can readily produce moderately slower, relatively natural-sounding speech using self-devised methods. Speakers’ and listeners’ perceptions of speech naturalness may differ considerably, however, and this must be considered during training.

Speech samples in this study were digitized and analyzed using the CSL, Model 4300B. Specifically, spectrographic and waveform displays were used for making the numerous precise durational measurements (e.g., pause time, syllabic rate, word duration, etc.) related to overall speech rate for the various rate reduction techniques.

“Nasalance, Nasality, Voice, and Articulation After Uvulopalatopharyngoplasty,” Van Lierde, Kristiane, John Van Borsel, and Mieke Moerman, Laryngoscope, Vol. 112, pp. 873-878, May 2002.

OBJECTIVES/HYPOTHESIS: The main purpose of the study was to determine the impact of uvulopalatopharygoplasty (UPPP) on nasalance and nasality. It was hypothesized that nasalance would change from the presurgical to the postsurgical condition because the surgical protocol involves removal of palatal tissue. An additional objective of the study was to provide objective and subjective data about changes in voice and articulation after UPPP. Because the surgical procedure of UPPP does not involve laryngeal tissue, it was hypothesized that the voice characteristics remain relatively stable. Because of removal of effective velar length, articulation problems of the uvular /R/ can occur in the Dutch language.

STUDY DESIGN: Prospective study in which 26 men were studied before (1 week before UPPP) surgery).

METHODS: The Nasometer was used to obtain nasalance scores. The mirror-fogging test, a perceptual evaluation of each subject’s readings, and the Gutzmann and the Bzoch hypernasality tests were used for the assessment of nasality. For the assessment of articulation, a phonetic analysis was performed. Voice assessment included a perceptual rating of the voice and a determination of fundamental frequency.

RESULTS: No significant differences were found between the conditions before and after surgery regarding nasalance (except for the vowel /i/), nasality, and voice. Regarding articulation, only 1 patient showed a derhotacized /R/.

CONCLUSIONS: The findings of the study indicate that UPPP does not have an impact on nasality, voice, and articulation. Regarding nasalance, no significant nasalance change occurred after UPPP, except for the high vowel /i/.

The Nasometer, Model 6200, was used to assess nasalance pre- and post-surgically in this study. Fundamental frequency measurements were made using the Multi-Dimensional Voice Program (MDVP), a software option for the Computerized Speech Lab (CSL).

“Acoustic Cues to the Voicing Feature in Tracheoesophageal Speech,” Searl, Jeffrey P. and Mary A. Carpenter, Journal of Speech, Language, and Hearing Research, Vol. 45, pp. 282-294,  April 2002.

Tracheoesophageal (TE) speakers often have difficulty producing the voiced/voiceless distinction. This limitation has been attributed to use of the pharyngoesophageal segment as the phonatory source. The nature of this tissue may preclude precise control of voicing onset, a contributing cue to a phoneme’s voicing feature, at least in laryngeal speech. The purpose of this study was to determine whether voiced and voiceless consonants produced by the TE speakers could be differentiated from those produced by laryngeal speakers using four acoustic measures associated with the voicing characteristic of consonants in fricative cognate pairs embedded in a carrier phrase. Three of the four acoustic measures contributed significantly to the discriminant models that differentiated accurately perceived TE and laryngeal samples. The three variables were consonant sound pressure level, consonant duration, and preceding vowel duration. In general, values for each measure were higher/longer for the TE group. The discriminant functions were interpreted as a reflection of the TE speaker attempts at overarticulation.

The CSL, Model 4300B, was used to make the voice onset time (VOT), preceding vowel duration, consonant duration, and consonant dB SPL measurements used in this study.

“Computer-Assisted Voice Analysis: Establishing a Pediatric Database,”Campisi, Paolo, Ted L. Tewfik, John J. Manoukian, Melvin D. Schloss, Elaine Pelland-Glais, and Nader Sadeghi, Archives of Otolaryngology - Head and Neck Surgery, Vol. 128, pp. 156-160, February 2002.

OBJECTIVES: To establish and characterize the first pediatric normative database for the Multi-Dimensional Voice Program, a computerized voice analysis system, and to compare the normative data with the vocal profiles of patients with vocal fold nodules.

DESIGNS: A cross-sectional, observational design was used to establish the normative database. The comparative study was completed using a case-control design.

SETTING: University-based outpatient pediatric otolaryngology clinic.

PARTICIPANTS: One hundred control subjects (50 boys and 50 girls) aged 4 to 18 years contributed to the normative database. The voices of 26 patients (19 boys and 7 girls) with bilateral vocal fold nodules were also analyzed.

MAIN OUTCOME MEASURES: Demographic data, including sex, age, height, weight, body mass index, and cigarette smoke exposure, were obtained. The Multi-Dimensional Voice Program extracted up to 33 acoustic variables from each voice analysis.

RESULTS: The mean (SEM) values of each of the acoustic variables are presented. At age 12, boys experience a dramatic decrease in fundamental frequency measurements. The voices of patients with vocal fold nodules had significantly elevated frequency perturbation measurements compared with control subjects (p<.001).

CONCLUSIONS: The vocal profile of children is uniform across all girls and prepubescent boys. Patients with vocal fold nodules demonstrated a consistent acoustic profile characterized by an elevation in frequency perturbation measurements. Normal acoustic reference ranges may be used to detect vocal fold pathologic abnormalities and to monitor the effects of voice therapy.

The Multi-Dimensional Voice Program (MDVP) used in conjunction with a CSL, Model 4300B was used for this pediatric normative data study.

“An Acoustic Analysis of Excellent Female Esophageal, Tracheoesophageal, and Laryngeal Speakers,” Bellandese, Mary H., Jay W. Lerman, and Harvey R. Gilbert, Journal of Speech, Language, and Hearing Research, Vol. 44, 1315-1320, December 2001.

Acoustic data for female esophageal speakers is sparse, particularly with regard to characteristics of female tracheoesophageal speakers. This study quantified and compared six acoustic characteristics of excellent female tracheoesophageal (TE), standard esophageal (SE), and laryngeal (LA) speakers. Results indicated there were no significant differences between TE and SE speakers with regard to mean Fo of sustained /a/, mean Fo (reading), signal-to-noise ratio, total duration of passage read, number of pauses, and syllables per minute. Significant differences were found between LA speakers and both alaryngeal groups for all variables, with the exception of mean Fo (reading). 

The Computerized Speech Lab (CSL, Model 4300B) was used for data acquisition of speech samples in this study.

“Laryngoscopic, Acoustic, and Environmental Characteristics of High-Risk Vocal Performers,” Hoffman-Ruddy, Bari, Jeffrey Lehman, Carl Crandell, David Ingram, and Christine Sapienza, Journal of Voice, Vol. 15, Number 4, pp. 543-552, December 2001.

Vocal performance often requires excessively high vocal demand. In particular “high risk” performers, a group of individuals who use their voices at their maximum effort level, are often exposed to unique vocal abuse characteristics which include high environmental and performance demands and inconsistencies of cast performance. Three categories of high-risk performers were studied: musical theater, choral ensemble, and street theater. Musical theater performers produce a Broadway, West End “belting” style voice. Street theater performers use a high-energy pitch-varying dialogue in order to imitate a desired character voice. Choral ensemble performance requires group cohesion and blending of four-part harmony. The melodies require sustained vocal durations within each of the respective registers. For each of these studied groups, vocal tasks of sustained production of /i/ and /a/ were subjected to analysis. Acoustic measures included fundamental frequency, standard deviation of fundamental frequency, jitter percent, shimmer percent, and noise-to-harmonic ratio. Laryngostroboscopic parameters were assessed during sustained /i/. Environmental acoustic sound field measurements were made using an A weighting and linear weighting sound pressure level. These weightings were used to describe noise levels and vocal output, respectively, within performance environments. Results of the analysis suggest that high-risk performers are a unique performance type defined by distinctive, acoustic, laryngostroboscopic, and environmental characteristics.

“A Comparison of Radiation-Induced and Presbylaryngeal Dysphonia,” Behrman, Allison, Allan L. Abramson, and David Myssiorek, Otolaryngology-Head and Neck Surgery, Vol. 125, Number 3, pp. 193-200, September 2001.

OBJECTIVE: The goal of this study was to assess voice after radiotherapy compared with patients with presbylaryngeal dysphonia.

STUDY DESIGN AND SETTING: Prospective assessment of 20 patients aged 60+ years who remained free of disease longer than 1 year after radiotherapy for T1 squamous cell carcinoma and retrospective review of 46 patients aged 60+ with presbylaryngeal dysphonia, conducted at a tertiary care, academic hospital. Assessment data included videostroboscopy, spectrography, voice range profile, and Voice Handicap Index.

RESULTS: Eighty percent of the radiotherapy patients reported a voice disorder. Acoustic data and functional measures reflected similar limitations and abnormalities for both groups. A high incidence of glottal gap in all patients may have been associated with increased mucosal stiffness in the radiotherapy group and vocal fold atrophy in the presbylaryngeal group.

CONCLUSION: Patient perception and functional outcome of voice were similar for both groups, despite differences in etiology of abnormal vocal fold vibratory behavior.

SIGNIFICANCE: Radiotherapy in older individuals may yield dysphonia that is no greater than that caused by normal aging.

Kay's RLS Stroboscopy System and Computerized Speech Lab (CSL) were used in this study. Specifically, spectrography and the Voice Range Profile (software option for CSL) were used for acoustic analysis.

“Failed Medialization Laryngoplasty: Management by Revision Surgery,” Woo, Peak, Adam W. Pearl, Ming-Wang Hsiung, and Peter Som, Otolaryngology–Head and Neck Surgery, Vol. 124, Number 6, June 2001.

“An Investigation of a Modal-Falsetto Register Transition Hypothesis Using Helox Gas,” Spencer, Martin L. and Ingo R. Titze, Journal of Voice, Vol. 15, Number 1, pp. 15-24, March 2001.

“Objective Voice Analysis after Autologous Fat Injection for Unilateral Vocal Fold Paralysis,” Hartel, Dana M., et al., Annals of Otology, Rhinology, and Laryngology, Vol. 110 (3), March 2001.

“Acoustic Comparison of Vowel Articulation in Normal and Reverse Phonation,” Robb, Michael, et al. JSLHR, Vol. 44, pp. 118-127, February 2001.

“Beginning to Talk at 20 Months: Early Vocal Development in a Young Cochlear Implant Recipient,” Ertmer, David J. and Jennifer A. Mellon, JSLHR, Vol. 44, pp. 192-206, February 2001.

“Acoustic, Aerodynamic, and Videostroboscopic Features of Bilateral Vocal Fold Lesions,” Rosen, Clark A., Lori E. Lombard, and Thomas Murray, Annals of Otology, Rhinology, and Laryngology, Vol. 109 (9), September 2000.

“The Dysphonia Severity Index: An Objective Measure of Vocal Quality Based on a Multiparameter Approach,” Wuyts, Floris L., Marc S. De Bodt,  et al. Journal of Speech, Language, and Hearing Research, Vol. 43, pp. 796-809,  June 2000.