The effects of vocal tract constrictions on aerodynamic measures in a synthetic vocal fold model.

According to nonlinear source-filter theory, as the strength of the coupling between the source and filter increases, typically by a decrease in the vocal tract cross-sectional area, the resultant increase in the inertance of the vocal tract yields an increase in the interactions between acoustic pressures within the vocal tract and the changing glottal airflow and/or the vibratory pattern of the vocal folds as noted in Titze [(2008). J. Acoust. Soc. Am. 123(4), 1902-1915]. The purpose of the current research was to examine the effects of parametric vocal tract constrictions mimicking epilaryngeal tube and lip narrowing on aerodynamic measures in a dynamic self-oscillating physical model of the vocal folds and vocal tract. Multilayered silicone vocal fold models were created based on Murray and Thomson [(2011). J. Visualized Exp. 58, e3498] and Murray and Thomson [(2012). J. Acoust. Soc. Am. 132(5), 3428-3438] and mounted to a simple synthetic trachea and supraglottal vocal tract model. Four constriction cross-sectional areas were examined at two locations (i.e., at the epilarynx and lip regions). Phonation threshold pressure and flow were measured at phonation onset and offset using four M5-CONV vocal fold models. Results indicated that both constriction magnitude and location are relevant factors in determining glottal aerodynamics. In general, a narrow epilarynx tube or lip constriction resulted in the lowest onset pressures and airflows while the no vocal tract condition resulted in the highest onset pressures and airflows.

Using a vertical three-mass computational model of the vocal folds to match human phonation of three adult males.

Computer models of phonation are used to study various parameters that are difficult to control, measure, and observe in human subjects. Imitating human phonation by varying the prephonatory conditions of computer models offers insight into the variations that occur across human phonatory production. In the present study, a vertical three-mass computer model of phonation [Perrine, Scherer, Fulcher, and Zhai (2020). J. Acoust. Soc. Am. 147, 1727-1737], driven by empirical pressures from a physical model of the vocal folds (model M5), with a vocal tract following the design of Ishizaka and Flanagan [(1972). Bell Sys. Tech. J. 51, 1233-1268] was used to match prolonged vowels produced by three male subjects using various pitch and loudness levels. The prephonatory conditions of tissue mass and tension, subglottal pressure, glottal diameter and angle, posterior glottal gap, false vocal fold gap, and vocal tract cross-sectional areas were varied in the model to match the model output with the fundamental frequency, alternating current airflow, direct current airflow, skewing quotient, open quotient, maximum flow negative derivative, and the first three formant frequencies from the human production. Parameters were matched between the model and human subjects with an average overall percent mismatch of 4.40% (standard deviation = 6.75%), suggesting a reasonable ability of the simple low dimensional model to mimic these variables.

Phonation threshold pressure using a 3-mass model of phonation with empirical pressure values.

Understanding the control parameters that influence phonation threshold pressure can have important implications for ease of phonation. Using a computer model of phonation can aid in studying parameters not easily controllable through human experimental work and may provide a means of explaining variations seen across human participants. A vertical 3-mass computer model of phonation with empirical driving pressures was used to obtain phonation threshold pressures for a variety of prephonatory conditions that may be realistically produced by humans. The resulting phonation threshold pressures are reasonable compared to results from human studies and may extend beyond the range of phonatory control parameters studied in human experiments. In addition, the present work adds a formula for calculating phonation threshold pressure based on the prephonatory glottal angle, the tension of the vocal folds, and the prephonatory diameter. Of special interest is that, as the prephonatory angle of convergence increases from 0 degrees (the rectangular glottis condition), the phonation threshold pressure increases in a nearly linear fashion.

Recent measurements with a synthetic two-layer model of the vocal folds and extension of Titze's surface wave model to a body-cover model.

The experiments of Mendelsohn and Zhang in 2011 (J. Acoust. Soc. Am. 130, 2961-2968) with six synthetic, two-layer models of the vocal folds were undertaken to better understand the role that the body layer plays in determining the properties of phonation. This rich data set provides an opportunity to extend Titze's surface wave model to a body-cover model. Much of Mendelsohn and Zhang's data can be interpreted with this model by assuming that the ratio of the spring constants of the two oscillators is that of the ratio of the Young's moduli for the two layers, and that the ratio of the masses of the oscillators is proportional to the ratio of the depths of the two layers.

Effects of the Lidcombe Program and Parent-Child Interaction Therapy on Stuttering Reduction in Preschool Children.

PURPOSE: The present study explored the effectiveness of the Lidcombe Program, the parent-child interaction therapy (PCIT) approach, and an integrated (Lid-PCIT) program on the treatment of children who stutter. METHODS: The present research was a single-subject study with an alternative treatment design. Participants were 6 preschool children who were randomly assigned into three groups. Each group received the entire indirect (PCIT), direct (Lidcombe), or integrated (Lid-PCIT) program and were assessed through severity rating (SR), and percent stuttered syllables (%SS), and video analysis. RESULTS: For all children the SR and the %SS were reduced but the percentage of non-overlapping data of the three interventions showed that it was reduced more in the Lidcombe and in the Lid-PCIT programs. CONCLUSIONS: This study provided preliminary evidence that Lidcombe, PCIT, and integrated programs were effective in reducing the SR and the %SS in preschool children who stutter. These results are potentially important as both indirect and direct interventions in the primary years can help children who stutter to overcome their disorder.

Entrance loss coefficients and exit coefficients for a physical model of the glottis with convergent angles.

Pressure distributions were obtained for 5°, 10°, and 20° convergent angles with a static physical model (M5) of the glottis. Measurements were made for minimal glottal diameters from d = 0.005-0.32 cm with a range of transglottal pressures of interest for phonation. Entrance loss coefficients were calculated at the glottal entrance for each minimal diameter and transglottal pressure to measure how far the flows in this region deviate from Bernoulli flow. Exit coefficients were also calculated to determine the presence and magnitude of pressure recovery near the glottal exit. The entrance loss coefficients for the three convergent angles vary from values near 2.3-3.4 for d = 0.005 cm to values near 0.6 for d = 0.32 cm. These coefficients extend the tables of entrance loss and exit coefficients obtained for the uniform glottis according to Fulcher, Scherer, and Powell [J. Acoust. Soc. Am. 129, 1548-1553 (2011)].

Gender Perception of Speech: Dependence on Fundamental Frequency, Implied Vocal Tract Length, and Source Spectral Tilt.

OBJECTIVE: To investigate how listeners use fundamental frequency, implied vocal tract length, and source spectral tilt to infer speaker gender. METHODS: Sound files each containing the vowels /i, æ, ɑ, u/ interspersed by brief silences were synthesized. Each of the 210 stimuli was a combination of 10 values for fundamental frequency and 7 values for implied vocal tract length (and the associated formant frequencies) ranging from male-typical to female-typical, and 3 values for source spectral tilt approximating the voice qualities of breathy, normal, and pressed. Twenty-three listeners judged each synthesized "speaker" as "female" or "male." Generalized linear mixed model analysis was used to determine the extent to which fundamental frequency, implied vocal track length, and spectral tilt influenced listener judgment. RESULTS: Increasing fundamental frequency and decreasing implied vocal tract length resulted in increased probability of female judgment. Two interactions were identified: An increase in fundamental frequency and also a decrease in source spectral tilt (more negative) resulted in a greater increase in the probability of female judgment when the vocal tract length was relatively short. CONCLUSIONS: The relationships among fundamental frequency, implied vocal tract length, source spectral tilt, and probability of female judgment changed across the range of normal values, suggesting that the relative contributions of fundamental frequency and implied vocal tract length to gender perception varied over the ranges studied. There was no threshold of fundamental frequency or implied vocal tract length that dramatically shifted the perception between male and female.

Viscous effects in a static physical model of the uniform glottis.

The classic work on laryngeal flow resistance by van den Berg et al. [J. Acoust. Soc. Am. 29, 626-631 (1957)] is revisited. These authors used a formula to summarize their measurements, and thus they separated the effects of entrance loss and pressure recovery from those of viscosity within the glottis. Analysis of intraglottal pressure distributions obtained from the physical model M5 [R. Scherer et al., J. Acoust. Soc. Am. 109, 1616-1630 (2001)] reveals substantial regions within the glottis where the pressure gradient is almost constant for glottal diameters from 0.005 to 0.16 cm, as expected when viscous effects dominate the flow resistance of a narrow channel. For this set of glottal diameters, the part of the pressure gradient that has a linear dependence on the glottal volume velocity is isolated. The inverse cube diameter of the Poiseuille expression for glottal flows is examined with the data set provided by the M5 intraglottal pressure distributions. The Poiseuille effect is found to give a reasonable account of viscous effects in the diameter interval from 0.0075 to 0.02 cm, but an inverse 2.59 power law gives a closer fit across all diameters.

Vocal Tract Discomfort Symptoms in Elementary and High School Teachers.

OBJECTIVES: The vocal tract discomfort scale is a self-rating seven-point Likert scale that quantifies frequency and severity of eight qualitative descriptors including burning, tight, dry, aching, tickling, sore, irritable, and lump in the throat, and ranges from 0 (never/none) to 6 (always/extreme; Mathieson et al. 2009). The objectives of the current study were to compare the vocal tract discomfort scale results between elementary school teachers and high school teachers and between male and female teachers using the Persian vocal tract discomfort scale. Also, teachers in different age ranges and with different experiences were compared regarding vocal tract discomfort symptoms. METHODS: The researchers chose 20 elementary and high schools by simple random sampling in Khorramabad, Iran. The survey was given to available teachers of the selected schools. Considering the inclusion criteria, required sample size, and after excluding questionnaires that were not correctly answered, 120 were selected such that 30 were chosen for each subgroup. Subjects consisted of 60 elementary school teachers (30 females and 30 males) with the mean age of 40.92 years (standard deviation = 6.07) and 60 high school teachers (30 females and 30 males) with the mean age of 40.67 years (standard deviation = 6.00). SPSS 25 was used for analyzing the data. RESULTS: Results indicated that the frequency and severity of the vocal tract discomfort in elementary school teachers were significantly higher than for the high school teachers with a medium to large effect size. Although the frequency and severity of the symptoms were higher in female compared with male teachers, those differences were not significantly different. Younger teachers had lower frequency and severity ratings of vocal tract discomfort symptoms than older teachers. Teaching experience was not an important factor in predicting vocal tract discomfort symptoms in teachers. CONCLUSIONS: The results of this study suggest that there is higher frequency, greater severity, and higher percentages of vocal tract discomfort symptoms in elementary compared with high school teachers. In addition, although the mean frequency and severity of vocal tract discomfort symptoms were not significantly different between females and males, females reported higher percentages of the symptoms. Because each of the eight vocal tract symptoms was experienced at the time of testing by between 42% (tightness) and 68% (dryness) of the participants, it is suggested that an educational program regarding vocal tract discomfort may be helpful for this profession.

Objective Measures of Two Musical Interpretations of an Excerpt From Berlioz's "La mort d'Ophélie".

OBJECTIVE/HYPOTHESIS: This study aimed to determine objective production differences relative to two emotional interpretations in performing an excerpt from a classical art song. The null hypothesis was proposed. METHODS: The first author recorded an excerpt from an art song. The excerpt was sung with two contrasting musical interpretations: an "empathetic legato" approach, and a "sarcastic" approach characterized by emphatic attacks. Microphone, airflow, and electroglottography signals were digitized. The vowels were analyzed in terms of intensity, long term average spectra, fundamental frequency (fo), airflow vibrato rate and extent, vowel onset slope, intensity comparison of harmonic frequencies, and glottal measures based on electroglottograph waveforms. Four consonant tokens were analyzed relative to airflow, voice onset time, and production duration. RESULTS & CONCLUSIONS: The emphatic performance had faster vowel onset, increased glottal adduction, increased intensity of harmonics in 2-3 kHz, increased intensity in the fourth and fifth formants, inferred subglottal pressure increase, increased airflow for /f/, and greater aspiration airflow for /p, t/. Vibrato extents for intensity, fo, and airflow were wider in the emphatic approach. Findings revealed larger EGGW25 and peak-to-peak amplitude values of the electroglottography waveform, suggesting greater vocal fold contact area and longer glottal closure for the emphatic approach. Long-term average spectrum analyses of the entire production displayed minor variation across all formant frequencies, suggesting an insignificant change in vocal tract shaping between the two approaches. This single-case objective study emphasizes the reality of physiological, aerodynamic, and acoustic production differences in the interpretive and pedagogical aspects of art song performance.

Chronic voice disorder after coronavirus disease 2019 infection and its treatment using the cricothyroid visor maneuver: a case report.

BACKGROUND: Regarding human coronavirus, the severe acute respiratory syndrome coronavirus 2 pandemic, the novelty of disease, and consequently the lack of studies, the etiology of dysphonia in patients with coronavirus disease 2019 is still unknown and needs to be investigated. The purpose of the current study is to investigate the effect of a new manual therapy technique, cricothyroid visor maneuver, on muscle tension dysphonia symptoms for a patient who had experienced dysphonia symptoms due to the coronavirus disease 2019 infection. CASE PRESENTATION: A 55-year-old retired Iranian teacher who was diagnosed with muscle tension dysphonia by an otolaryngologist participated in this study. Fifty days before being referred to an otolaryngologist, he was diagnosed with coronavirus disease 2019 on the basis of the results of a standard laboratory test, namely real-time polymerase chain reaction. Treatment was provided in ten sessions. Pre- and post-treatment audio recordings of sustained vowels, selected sentences, and connected speech samples were submitted for auditory perceptual and acoustic analysis to assess the effects of the treatment program. Also, videolaryngostroboscopy voice quality perceptions by the patient, both before and after therapy, were assessed. The reduction in all features of the Consensus Auditory-Perceptual Evaluation of Voice was observed. The results of acoustic assessment showed that jitter (35.13%) and shimmer (20.48%) decreased; moreover, the harmonics-to-noise ratio (1.17%), cepstral peak prominence smoothed (28.53%) and maximum phonation time (15.5%) increased after treatment sessions. The scores of four parameters of Stroboscopy Examination Rating Form (SERF) form changed after cricothyroid visor maneuver therapy. Also, the visual analog scales score at the pre-treatment assessment was 40, and increased to 90 at the post-treatment assessment. CONCLUSIONS: The effectiveness of cricothyroid visor maneuver therapy on dysphonia associated with coronavirus disease 2019 was investigated in the current study. This case study has highlighted chronic dysphonia after coronavirus disease 2019 infection, and suggests that the cricothyroid visor maneuver therapy approach may have positive outcomes for patients with muscle tension dysphonia with this background.

Vocal Tract Discomforts among Smokers.

INTRODUCTION: Smoking is a dangerous behavior for the human body and the vocal tract. Smoking can cause several laryngeal and vocal tract symptoms in smokers. One of these symptoms can be physical discomfort experienced by this population. Therefore, the aim of the present study was to investigate vocal tract discomfort (VTD) in smokers compared to healthy non-smoker participants. MATERIALS AND METHODS: The smokers group was forty-eight men with a mean age of 47.54 ± 9.21 years, and the matched non-smokers group was 48 men with a mean age of 44.88 ± 10.81 years. The participants underwent vocal tract discomfort assessment using the Persian version of the VTD scale. Statistical Package for the Social Science (SPSS) was used for statistical analysis and the Mann-Whitney U test was used to compare variables between groups. RESULTS: The smokers more frequently had VTD symptoms (P < 0.05) than non-smokers for all items of the VTD scale with the exception of aches. Also, smokers had more significant VTD severity in all items than non-smokers (P < 0.05). Moreover, there were significant statistical differences between the total score of both frequency and severity of VTD between smokers and non-smokers. The most to the least VTD symptoms in smokers were irritation, sore, tickling, burning, tightness, lump in the throat, dry, and aching symptoms, respectively. CONCLUSION: The present study suggests that smoking can cause more physical vocal tract discomfort in smokers compared to non-smokers. These results can inform future research and interventions in the smoker population.

Development and Psychometric Evaluation of the Laryngeal Palpation Pain Scale (LPPS).

INTRODUCTION: One of the most important assessment and therapy methods for patients with muscle tension dysphonia (MTD) and other voice disorders is laryngeal palpation. However, there is no comprehensive scale for measuring pain during laryngeal palpation. The goal of the present study was to develop and validate a new scale to evaluate pain during palpation for patients with MTD. METHODS: The present study consisted of two phases: (1) Development of the Laryngeal Palpation Pain Scale (LPPS) based on an in-depth literature review, the palpatory evaluation of MTD patients, interviews with experts in the field of voice disorders, and consultation with a registered pain expert, and (2) evaluation of the validity and reliability of the LPPS. The validity of the LPPS was investigated using qualitative and quantitative content validity, qualitative face validity, discriminant validity, and convergent validity. Content validity of the LPPS was assessed by experts' opinions (10 speech-language pathologists and five laryngologists), and face validity was investigated using the opinions of speech-language pathologists. The reliability of the LPPS was determined using test-retest and inter-rater reliability. RESULTS: The item generation phase of the study led to the development of a scale to assess pain during palpation that included eleven locations in the neck region for palpatory assessment. These 11 items were divided into 13 different items (neck locations) based on the opinions of the experts. The content validity ratio values of all scale items were higher than 0.78. The content validity index (CVI) value for each of the items of the scale was higher than 0.79 and for the entire scale CVI (S-CVI) was 0.915. The results of the reliability of the LPPS items were satisfactory with weighted kappa values ranging from 0.655 to 1 for the test-retest and 0.77-1 for the inter-rater reliability. Convergent validity of the LPPS was shown with a significant positive correlation (r = 0.68) between the LPPS and the pain severity of vocal tract discomfort (P < 0.001). Moreover, MTD patients had more pain severity than the control group in all items of the LPPS (P < 0.05) except for the submental item (P = 0.89). These results indicate that the LPPS can differentiate MTD patients from healthy subjects. The final version of the LPPS includes 13 potential pain locations. The severity of pain at each of these locations is determined on a numeric pain rating scale of zero (no pain) to ten (the most severe pain). CONCLUSION: The study showed that the LPPS is a valid and reliable scale to assess pain in MTD patients during palpation evaluations. More studies are recommended for further psychometric evaluation of the LPPS including responsiveness to change (the use in before-and-after intervention studies) and concurrent validity of the LPPS. The LPPS can be used for clinical and research purposes.

Ventricular pressures in phonating excised larynges.

Pressure in the laryngeal ventricle was measured with a beveled needle connected to a pressure transducer in excised canine larynges. Air pressures within the ventricle were obtained for different adduction levels of the true vocal folds (TVFs), false vocal folds (FVFs), and subglottal pressures (Ps). Results indicated that the air pressures in the ventricle appear to be strongly related to the motion of the FVFs rather than to the effects of TVF vibration. Both dc and ac pressures depend on FVF adduction, amplitude of motion of the FVFs, and whether the FVFs touch each other during the vibratory cycle. Mean and peak-to-peak pressures in the ventricle were as high as 65% of the mean and peak-to-peak Ps, respectively, when the FVFs vibrated with large amplitude and contact each cycle. If the glottis was not closed, a medial movement of the FVFs appeared to create a positive pressure pulse on the Ps signal due to an increase in the laryngeal flow resistance. The electroglottograph signal showed evidence of tissue contact for both the TVFs and the FVFs. The study suggests that the laryngeal ventricle acts as a relatively independent aero-acoustic chamber that depends primarily upon the motion of the FVFs.

The effect of entrance radii on intraglottal pressure distributions in the divergent glottis.

Modeling laryngeal aerodynamics requires specification of the glottal geometry. Changing the glottal exit radius alters the intraglottal pressure distributions in the converging glottis [Scherer et al., J. Acoust. Soc. Am. 110, 2267-2269 (2001)]. This study examined the effects of the glottal entrance radius on the intraglottal pressure distributions for divergent angles of 5°, 10°, 20°, 30°, and 40°. Glottal airflow and minimal glottal diameter were held constant at 73.2 cm(3)/s and 0.02 cm, respectively. The computational code FLUENT was used to obtain the pressure distributions. Results suggest that a smaller glottal entrance radius tends to (1) lower the transglottal pressure (reduce glottal flow resistance), although this is angle dependent, (2) make the pressure dip near the glottal entrance more negative in value, (3) increase the slope of the pressure distribution just upstream of the glottal entrance, and (4) make the initial pressure recovery (rise) in the glottis steeper. A general empirical equation for transglottal pressure as a function of radius, angle, and separation point location is offered. These results suggest that glottal entrance curvature for the divergent glottis significantly affects the driving pressures on the vocal folds, and needs to be well specified when building computational and physical models.

Phonation threshold pressure and the elastic shear modulus: comparison of two-mass model calculations with experiments.

Ishizaka and Flanagan's classic two-mass model of vocal fold motion is applied to small oscillations where the equations become linear and the aerodynamic driving force is described by an effective stiffness. The solution of these equations includes an analytic formula for the two eigenfrequencies; this shows that conjugate imaginary parts of the frequencies emerge beyond eigenvalue synchronization and that one of the imaginary parts becomes zero at a pressure signaling the instability associated with the onset of threshold. Using recent measurements by Fulcher et al. of intraglottal pressure distributions [J. Acoust. Soc. Am. 129, 1548-1553 (2011).] to inform the behavior of the entrance loss coefficients, an analytic formula for threshold pressure is derived. It fits most of the measurements Chan and Titze reported for their 2006 physical model of the vocal fold mucosa. Two sectors of the mass-stiffness parameter space are used to produce these fits. One is based on a rescaling of the typical glottal parameters of the original Ishizaka and Flanagan work. The second requires setting two of the spring constants equal and should be closer to the experimental conditions. In both cases, values of the elastic shear modulus are calculated from the spring constants.

The effects of aging on acoustic parameters of voice.

BACKGROUND/AIMS: There are no studies of the phonatory parameters of elderly Iranian speakers. The purpose of this study was to obtain normative acoustic data for a group of elderly Iranian male and female speakers over 70 years of age. Four selected acoustic parameters [fundamental frequency (F0), jitter, shimmer, and harmonics-to-noise ratio] were obtained and compared to a group of young and middle-aged speakers. METHODS: Subjects were 21 Iranian elderly men and 20 Iranian elderly women. The age range for both male (mean ± SD: 77.09 ± 5.84) and female subjects (77.55 ± 4.34) was 70-90 years. The control group consisted of 40 Iranian young and middle-aged adults who were 20-49 years old (20 men and 20 women). The age range for the females was 23-40 years (30 ± 4.76) and for the males it was 21-49 years (30.1 ± 8.51). Each subject phonated 5/a/vowels with constant pitch and loudness for at least 5 s. The mid 3-second portion of the tokens was analyzed using the Dr. Speech 4.3u software (subprogram: Vocal Assessment; Dr. Speech, Tiger Electronics, Seattle, Wash., USA). RESULTS: F0 was greater for elderly males than for young and middle-aged males. Conversely, F0 was greater for young and middle-aged females than for elderly females. Average shimmer was significantly higher in elderly males than in elderly females. Likewise, jitter was significantly higher in elderly males than in elderly females. Both shimmer and jitter were significantly greater in elderly speakers than in the young and middle-aged speakers. In addition, the harmonics-to-noise ratio was significantly greater for young and middle-aged males and females than for elderly males and females. CONCLUSIONS: The results of this study indicate that elderly Iranian speakers had significantly greater vocal instability than young and middle-aged Iranian adults, as measured by the selected acoustic parameters. As the elderly population in Iran and the world continues to increase rapidly, studies of this kind are needed for researchers, educators, and practitioners to better understand the effects of aging on all aspects of human speech-language communication. Voice is an important factor for communication, and its change with age alters the communication process.

Vocal Fry Patterns While Reading.

INTRODUCTION: The use of vocal fry is common in running speech and has potential psychosocial and vocal health consequences. Determining the different patterns of vocal fry is relevant to differentiating phonatory function, understanding cultural and linguistic use of vocal fry, and clinical diagnostics and intervention. The purpose of this project was to study and categorize patterns of vocal fry in running speech. METHODOLOGY: Analyses were performed on recordings of the Rainbow Passage read out loud by five healthy females 18-21 years old. Praat was used to create audio files with text grids. The audio recordings were examined visually (the audio signal and its spectrogram) and perceptually in order to determine different patterns of vocal fry seen in the audio signal. Criteria for detecting vocal fry were (1) the presence of an acoustic transient (a relatively large and fast dip in acoustic pressure, presumably near glottal closure) with a relatively long cycle period compared to normal phonation periods, or (2) a frequency at or lower than approximately an octave below the nearby normal speaking fundamental frequency. RESULTS: There were 174 total vocal fry samples obtained from the recordings. Six vocal fry patterns were observed. The patterns were: single pulse fry (FRY1), double pulse fry (FRY2), multiple pulse fry (FRY3), period doubling fry (FRY4), inaudible fry (FRY5), and indeterminate vocal fry (FRY6). Single pulse fry was divided into a single (one) pulse fry cycle (FRY1a), a series of even single pulse fry cycles (FRY1b), and a series of uneven single pulse fry cycles (FRY1c). Double pulse fry was divided into a primary then another primary pulse fry cycle (FRY2a), a secondary then a primary pulse fry cycle (FRY2b), and a primary then a secondary pulse fry cycle (FRY2c). Multiple pulse fry, where a higher frequency was modulated by a lower frequency, was divided into the higher frequency being near the speaking fundamental frequency (FRY3a) and the higher frequency being inconsistent or well below the expected speaking fundamental frequency (FRY3b). The category single pulse fry had the most samples, with 76% of the total occurrences, followed by period doubling 13%, and the rest 11%. Relative to where the fry patterns occurred within syllables, 36% occurred at the onset of the syllable, 26% early in the syllable, 25% later in the syllable, and 13% at the end of the syllable. These tallies did not include the sixth category, indeterminate vocal fry (FRY6), which was not included in the study proper but recognized as indicating complicated patterns that did not fall within the first five categories. CONCLUSIONS: Vocal fry is a complex, multifaceted phenomenon. The results of this study suggest that there are identifiable patterns of vocal fry. These patterns need to be differentiated especially regarding the glottal adductory nature and phonatory function of each pattern, glottal closure appearing to be the primary physiological causative factor of the salient negative pressure dips (the adduction behavior will be reported in a study in progress). Further research is necessary to determine other potential categories of vocal fry, determine if there are individual idiosyncratic patterns of vocal fry, determine possible differences in vocal fry produced by individuals of different ages and gender expression and other factors, and research the physiologic, acoustic, aerodynamic, and perceptual reality of each pattern.

Construct and Discriminant Validity of the Persian Version of the Consensus Auditory Perceptual Evaluation of Voice (CAPE-V).

PURPOSE: Five dimensions of voice assessment are considered as visual evaluation, videostroboscopy, acoustic, aerodynamic, patient-based, and auditory-perceptual. Auditory-perceptual voice assessment scales are the standard scales for clinicians to document voice therapy outcomes in dysphonic patients. The primary objective of the present study was to investigate the construct and discriminant validities of the Persian Version of the CAPE-V (ATSHA). A secondary objective was to determine the differences between experienced and inexperienced raters in the auditory-perceptual assessment of voice. METHOD: Forty normal and forty individuals with dysphonia were rated by five experienced and five inexperienced raters. Pathological subgroups were vocal fold nodules, vocal fold polyps, unilateral vocal fold paralysis (UVFP), and Reinke's edema. The differences between normal and pathologic groups were observed by independent t tests for all perceptual parameters (P < 0.05). Construct validity was documented for the scale of interest. The Kruskal-Wallis and Mann-Whitney comparisons were used to examine discriminant validity. RESULTS: Findings of these tests showed that scores of all pathological subgroups were significantly different except for the parameter of "strain" in sustained vowels (P < 0.05). Results of the Wilcoxon Matched-Pairs Signed Rank Test indicated that experienced and inexperienced raters were significantly different in auditory-perceptual judgments of voice. CONCLUSION: It seems that the Persian Version of the CAPE-V is a consistent predictor of normal and pathological voices. Moreover, we found that experienced listeners have different auditory-perceptual skills in evaluation of voice that make them more precise than inexperienced listeners.

Phonation threshold pressure: comparison of calculations and measurements taken with physical models of the vocal fold mucosa.

In an important paper on the physics of small amplitude oscillations, Titze showed that the essence of the vertical phase difference, which allows energy to be transferred from the flowing air to the motion of the vocal folds, could be captured in a surface wave model, and he derived a formula for the phonation threshold pressure with an explicit dependence on the geometrical and biomechanical properties of the vocal folds. The formula inspired a series of experiments [e.g., R. Chan and I. Titze, J. Acoust. Soc. Am 119, 2351-2362 (2006)]. Although the experiments support many aspects of Titze's formula, including a linear dependence on the glottal half-width, the behavior of the experiments at the smallest values of this parameter is not consistent with the formula. It is shown that a key element for removing this discrepancy lies in a careful examination of the properties of the entrance loss coefficient. In particular, measurements of the entrance loss coefficient at small widths done with a physical model of the glottis (M5) show that this coefficient varies inversely with the glottal width. A numerical solution of the time-dependent equations of the surface wave model shows that adding a supraglottal vocal tract lowers the phonation threshold pressure by an amount approximately consistent with Chan and Titze's experiments.