Journal of Voice

Published by Elsevier BV

Print ISSN: 0892-1997


Speaking Fo and cepstral periodicity analysis of conversational speech in a 105-year-old woman: Variability of aging effects
  • Article

October 1996


29 Reads


Peter B. Mueller
We investigated speaking fundamental frequency and periodicity of voicing during conversational speech in a 105-year-old woman. Analyses revealed higher mean speaking fundamental frequency compared to previously published data obtained from elderly women. In the absence of normative data, the results of cepstrum analyses performed on vowels produced during connected speech revealed less periodicity for the 105-year-old woman's voice than for a 35-year-old woman's voice. The main finding of this study indicates that previously reported group trends regarding aging effects on mean speaking fundamental frequency of the female voice cannot simply be attributed to all elderly individuals. These results stress the importance, for clinical and research purposes, of recognizing the existence of considerable intra- as well as intersubject variability in the effects of aging on the voice.

Data on subglottal pressure and SPL at varied vocal loudness and pitch in 8- to 11-year-old children

July 1998


76 Reads

Phonation threshold pressure has been defined as the minimum subglottal pressure to generate phonation. Previous research has indicated that children may habitually employ higher subglottal pressures than adults. In the present investigation sound pressure level (SPL) and subglottal pressures at different pitch levels were measured at and above phonation threshold in nine children. Phonation threshold values were scattered in reasonable agreement with Titzes' prediction, although a discrepancy was noted regarding the frequency dependence in some voices. At normal conversational loudness and loudest level of phonation the children's Ps values were between two to four and four to eight times the predicted threshold values, respectively. At normal conversational loudness and habitual pitch subglottal pressures were lower than those previously observed for children, but similar to those found for female adults. The SPL in softest and loudest phonation were somewhat lower as compared to previous phonetogram data for children and for female adults. At normal loudness and habitual pitch the SPL values were similar to those of female adults. For a doubling of Ps mean SPL increased by 10.5 dB on the average.

Aerodynamic Measurements: Normative Data for Children Ages 6:0 to 10:11 Years

September 2005


160 Reads

Normative measures of open quotient, speed quotient, maximum flow declination rate (MFDR), and subglottal pressure were determined for 75 children between the ages of 6 years 0 months and 10 years 11 months. The participants produced a sustained /a/ at low, comfort, and high pitches for a minimum of 5 seconds, and five to seven repetitions of /pa/ at low, comfort, and high pitches. No statistically significant differences were found in the mean measures of any aerodynamic variables (open quotient, speed quotient, maximum flow declination rate, subglottal pressure) between the frequency levels (low, comfort, high pitches). Also, no strong evidence (P > .05) exists that age or sex effect differed between the frequency levels (low, comfort, high) for any of the aerodynamic measures. For /a/ response tasks, mean open quotient measures increased slightly from low to comfort frequency and from comfort to high frequency. Mean speed quotient measures showed minimal differences between low and comfort frequency, with decreased mean measures for high frequency. Mean MFDR measures increased from low to comfort frequency and from comfort to high frequency. Mean subglottal pressure measures increased slightly from low to comfort frequency and from comfort to high frequency.

G. Paul Moore Lecture--1993. New voices for old

July 1995


8 Reads

Otolaryngology and voice science have entered the era of "phonosurgery." Several techniques allow voice professionals to intervene to restore or modify the voice in patients with immobile vocal folds and other problems related to voice production. It is necessary and appropriate that physicians and speech and language pathologists critically examine what has been accomplished and what may yet be possible for further voice improvement.

Dynamic Biomechanical Strain Inhibits IL-1β–induced Inflammation in Vocal Fold Fibroblasts

December 2007


29 Reads






Despite the fact that vocal folds are subjected to extensive mechanical forces, the role of mechanical strain in vocal fold wound healing has been overlooked. Recent studies on other tissues have demonstrated that low physiological levels of mechanical forces are beneficial to injured tissues, reduce inflammation, and induce synthesis of matrix-associated proteins essential for enhanced wound healing. In this study, we speculated that mechanical strain of low magnitudes also attenuates the production of inflammatory mediators and alters the extracellular matrix synthesis to augment wound healing in cultured vocal fold fibroblasts. To test this hypothesis, fibroblasts from rabbit vocal folds were isolated and exposed to various magnitudes of cyclic tensile strain (CTS) in the presence or absence of interleukin-1beta (IL-1beta). Results suggest that IL-1beta activates proinflammatory gene transcription in vocal fold fibroblasts. Furthermore, CTS abrogates the IL-1beta-induced proinflammatory gene induction in a magnitude-dependent manner. In addition, CTS blocks IL-1beta-mediated inhibition of collagen type I synthesis, and thereby upregulates collagen synthesis in the presence of IL-1beta. These findings are the first to reveal the potential utility of low levels of mechanical signals in vocal fold wound healing, and support the emerging on vivo data suggesting beneficial effects of vocal exercise on acute phonotrauma.

24 Hours prior to curtain

April 2000


26 Reads

A retrospective review was conducted of 40 singers presenting with acute voice problems prior to performance. The purpose of this study was to determine the reasons for seeking emergent voice treatment, the types of acute voice disorders, and the performance outcome. The patients were assessed by age, singing style, years of experience, chief complaint, laryngovideostroboscopic findings, and treatment regimens. The outcomes were classified as full, restricted, or no performance. The majority of patients were classical singers. Laryngovideostroboscopy frequently revealed a pattern of early glottic contact at the mid-portion of the membranous vocal fold in patients with acute laryngitis. Experienced singers uniformly sought treatment many days before their performance compared with inexperienced singers who presented closer in time to performance. Six patients initially withheld information, which had a bearing on their acute management. The results of this study suggest that there is a need to accurately diagnose and treat the singer's emergent problem and educate singers regarding early evaluation of medical problems. With modern evaluation techniques and multi-modality treatment, 85% of the singers proceeded to full performance without negative sequelae.

Formant frequency development: 15 to 36 months
  • Article
  • Full-text available

October 1997


129 Reads

Developmental characteristics of formant 1 (F1) and formant 2 (F2) are reported for spontaneous vocalizations produced by four young children. Each child was systematically sampled at between 15 and 36 months of age. Results indicated that both F1 and F2 remained relatively unchanged prior to 24 months of age. Significant decreases in average F1 and F2 occurred between 24 and 36 months. When F1 and F2 values were categorized according to tongue elevation and tongue advancement, the most significant changes were associated with high/back articulations. The pattern of formant frequencies noted in the present group of children appears to reflect developmental changes in vocal tract growth and reconfiguration.

The Effect of Noise on Computer-Aided Measures of Voice: A Comparison of CSpeechSP and the Multi-Dimensional Voice Program Software Using the CSL 4300B Module and Multi-Speech for Windows

March 2003


123 Reads

The effect of noise on computer-derived samples of voice was compared across three different hardware/software configurations. The hardware/software systems included a stand-alone A/D converter (CSL Module 4300B) coupled to a custom Pentium PC used in conjunction with the Multi-Dimensional Voice Program (MDVP) software, and a Creative Labs A/D converter coupled to the same custom PC under software control of MDVP/Multispeech and CSpeechSP. Voice samples were taken from 10 female subjects, then mixed with computer fan noise creating three different signal-to-noise (S/N) levels. Mixed signals were analyzed on the three hardware/software systems. Results revealed that fundamental frequency was most resistant to the degradation effect of noise across systems; jitter and shimmer values, however, were more variable across all configurations. Jitter and shimmer values were significantly higher under certain S/N levels for the MDVP 4300B based system as compared to MDVP for Multi-Speech and CSpeechSP. The findings punctuate the need for sensitivity to recording environments, careful selection of hardware/software equipment arrays, and the establishment of minimal recording conditions (>25 dBA S/N) for voice sampling and analysis using computer-assisted methods.

A study of the effectiveness of voice therapy in the treatment of 45 patients with nonorganic dysphonia

March 1999


231 Reads

Forty-five patients diagnosed as having nonorganic dysphonia were assigned in rotation to 1 of 3 groups. Patients in group 1 received no treatment and acted as a control group. Patients in groups 2 and 3 received a program of indirect therapy and direct with indirect therapy, respectively. A range of qualitative and quantitative measures were carried out on all patients before and after treatment to evaluate change in voice quality over time. Results revealed a significant difference between the 3 treatment groups in the amount of change for the voice severity, electrolaryngograph, and shimmer measurements and on ratings provided by a patient questionnaire (P<0.05). However, other measures failed to show significant differences between the 3 groups. Most of the patients (86%) in group 1 showed no significant change on any of the measures. Some patients in treatment group 2 (46%) showed significant change in voice quality. Fourteen out of 15 patients (93%) in treatment group showed significant changes in voice quality.

Ultrastructural Evaluation of 585-nm Pulsed-Dye Laser-Treated Glottal Dysplasia

February 2007


17 Reads

To describe the ultrastructural changes occurring within pulsed-dye laser (PDL)-treated glottal tissues. Prospective. Nine patients presenting with glottal dysplasia requiring biopsy to rule out microinvasive carcinoma were enrolled in this prospective study. At least two samples were obtained in each case: one from a PDL-treated area and another from a non-PDL-treated area (obtained from a nonphonatory region as an internal control). In some cases, a third sample was obtained from the junction between PDL- and non-PDL-treated areas. All samples were examined with light microscopy (H and E stain) and transmission electron microscopy. Observations were made of morphological changes within the epithelium, epithelial/ superficial lamina propria (SLP) junction, and the lamina propria of tissues treated with the PDL. Eight of nine patients were followed for a period of 9-25 months (mean, 18 months) with two recurrences that were retreated with awake-PDL and followed for an additional 8.3 and 9.5 months without recurrence. Vocal fold appearance returned to normal within 3-4 weeks posttreatment. Intraepithelial desmosome junctions were preferentially destroyed, and regional blood vessels were coagulated. The PDL consistently caused a separation of epithelial cells away from the basement membrane. The PDL allowed for both a surgical and a nonsurgical multimodality method for treatment of precancerous lesions with minimal effects on the SLP.

Effects of Inhalatory Abdominal Wall Movement on Vertical Laryngeal Position During Phonation

October 2001


95 Reads

The configuration of the body resulting from inhalatory behavior is sometimes considered a factor of relevance to voice production in singing and speaking pedagogy and in clinical voice therapy. The present investigation compares two different inhalatory behaviors: (1) with a "paradoxical" inward movement of the abdominal wall, and (2) with an expansion of the abdominal wall, both with regard to the effect on vertical laryngeal position during the subsequent phonation. Seventeen male and 17 female healthy, vocally untrained subjects participated. No instructions were given regarding movements of the rib cage. Inhaled air volume as measured by respiratory inductive plethysmography, was controlled to reach 70% inspiratory capacity. Vertical laryngeal position was recorded by two-channel electroglottography during the subsequent vowel production. A significant effect was found; the abdomen-out condition was associated with a higher laryngeal position than the abdomen-in condition. This result apparently contradicted a hypothesis that an expansion of the abdominal wall would allow the diaphragm to descend deeper in the torso, thereby increasing the tracheal pull, which would result in a lower laryngeal position. In a post-hoc experiment including 6 of the subjects, body posture was studied by digital video recordings, revealing that the two inhalatory modes were clearly associated with postural changes affecting laryngeal position. The "paradoxical" inward movement of the abdominal wall was associated with a recession of the chin toward the neck, such that the larynx appeared in a lower position in the neck, for reasons of a postural change. The results suggest that the laryngeal position can be affected by the inhalatory behavior if no attention is paid to posture, implying that instructions from clinicians and pedagogues regarding breathing behavior must be carefully formulated and adjusted in order to ensure that the intended goals are reached.

Active and Passive Properties of Canine Abduction/Adduction Laryngeal Muscles

October 2005


53 Reads

Active and passive characteristics of the canine adductor- abductor muscles were investigated through a series of experiments conducted in vitro. Samples of canine posterior cricoarytenoid muscle (PCA), lateral cricoarytenoid muscle (LCA), and interarytenoid muscle (IA) were dissected from dog larynges excised a few minutes before death and kept in Krebs-Ringer solution at a temperature of 37 degrees C +/- 1 degree C and a pH of 7.4 +/- 0.05. Active twitch and tetanic force was obtained in an isometric condition by applying field stimulation to the muscle samples through a pair of parallel-plate platinum electrodes. Force and elongation of the samples were obtained electronically with a dual-servo system (ergometer). The results indicate that the twitch contraction times of the three muscles are very similar, with the average of 32 +/- 1.9 ms for PCA, 29 +/- 1.6 ms for LCA, and 32 +/- 2.4 ms for IA across all elongations. Thus, PCA, LCA, and IA muscles are all faster than the cricothyroid (CT) muscles but slower than the thyroarytenoid (TA) muscles. The tetanic force response times of these muscles are also similar, with a maximum rate of force increase of 0.14 N/ms.

Botulinum Toxin Therapy for Abductor Spasmodic Dysphonia

April 2006


112 Reads

Botulinum toxin has been widely accepted as an effective therapy for controlling the symptoms of adductor spasmodic dysphonia (ADSD). Reported experience with botulinum treatment for abductor spasmodic dysphonia (ABSD) has been less impressive. Factors that may impair outcomes for ABSD include differences in the pathophysiology of ADSD and ABSD and limitation of maximal dose from airway restriction with posterior cricoarytenoid muscle (PCA) weakness. We report our experience with botulinum injection of the PCA with an asymmetric dose escalation protocol, based on clinical observations that in ABSD, abductor spasms are often stronger on one side, usually the left. The nondominant side was injected with 1.25 units. Dominant side dose began at 5 units, with step-wise increments of 5 units per week until one of three endpoints was reached: Elimination of breathy voice breaks, complete abductor paralysis of the dominant side, or airway compromise. Fourteen of 17 patients achieved good or fair voice, with dominant-side doses ranging from 10 to 25 units. Exercise intolerance limited PCA dose in two patients. One patient had persisting breathiness that improved with medialization thyroplasty. Asymmetric botulinum toxin injection into PCA muscles can suppress abductor spasm in patients with ABSD, but breathiness may persist, because of inadequate glottal closure.

Inspiratory pressure threshold training for upper airway limitation: A case of bilateral abductor vocal fold paralysis

October 2003


198 Reads

A single subject design was used to determine if pressure threshold training strengthens the inspiratory muscles in a subject with a limited glottal airway as well as diminish dyspnea and improve parameters of speech. The subject was a 19-year-old woman whose glottal airway was limited due to bilateral abductor vocal fold paralysis following a thyroidectomy. A 5-week inspiratory muscle strength-training program was implemented using a pressure-threshold trainer to strengthen the inspiratory muscles with the intent of enabling the generation of higher inspiratory pressures. The pressure threshold on the trainer was set at 75% of the subject's maximum inspiratory pressure (MIP). The subject was required to generate sufficient inspiratory pressure to bring air through the trainer during an inspiratory maneuver. MIP was the dependent variable used as an indication of inspiratory muscle strength. MIP increased by 47% following the training program. Maximal minute ventilation and oxygen uptake increased posttraining. Dyspnea during exercise and speech decreased as reported by the subject. Total reading duration and pause duration demonstrated a declining trend during connected speech. The results indicated that inspiratory muscle training using a pressure threshold device improves functional tasks such as exercise and speech in a subject with upper airway limitation.

Acoustic Measures of Symptoms in Abductor Spasmodic Dysphonia

October 2001


189 Reads

Speech of patients with abductor spasmodic dysphonia (ABSD) was analyzed using acoustic analyses to determine: (1) which acoustic measures differed from controls and were independent factors representing patients' voice control difficulties, and (2) whether acoustic measures related to blinded perceptual counts of the symptom frequency in the same patients. Patients' voice onset time for voiceless consonants in speech were significantly longer than the controls (p = 0.015). A principle components analysis identified three factors that accounted for 95% of the variance: the first factor included sentence and word duration, frequency shifts, and aperiodic instances; the second was phonatory breaks; and the third was voice onset time. Significant relationships with perceptual counts of symptoms were found for the measures of acoustic disruptions in sentences and sentence duration. Finally, a multiple regression demonstrated that the acoustic measures related well with the perceptual counts (r2 = 0.84) with word duration most highly related and none of the other measures contributing once the effect of word duration was partialed out. The results indicate that some of the voice motor control deficits, namely aperiodicity, phonatory breaks, and frequency shifts, which occur in patients with ABSD, are similar to those previously found in adductor spasmodic dysphonia. Results also indicate that acoustic measures of intermittent disruptions in speech, voice onset time, and speech duration are closely related to the perception of symptom frequency in the disorder.

FIGURE 1. Mean semitone difference scores for individuals with accurate and inaccurate pitch matching abilities in four stimuli conditions. 
Fundamental Frequencies for Each Participant's Own Voice Sample and Digitally Derived Samples Used for Pitch Discrimination and Pitch Matching Tasks
Individual Means and Standard Deviations of Absolute Semitone Differences for the Three Conditions of the Pitch Matching Task
Pitch Discrimination and Pitch Matching Abilities

August 2008


295 Reads

Various stimulus types have been investigated in pitch discrimination and pitch matching tasks. However, previous studies have not explored the use of recorded samples of an individual's own voice in performing these two tasks. The purpose of this study was to investigate pitch discrimination and pitch matching abilities using three stimuli conditions (participant's own voice, a neutral female voice, and nonvocal complex tones) to determine if pitch discrimination and/or pitch matching abilities are influenced by the type of stimuli presented. Results of the pitch discrimination tasks yielded no significant difference in discrimination ability for the three stimuli. For the pitch matching tasks, a significant difference was found for the participants' voice versus neutral female voice and the participants' voice versus tonal stimuli. There was no significant difference in pitch matching ability between the neutral female voice and the tonal stimuli. There was no significant correlation between pitch discrimination and pitch matching abilities for any of the three stimuli types. These results suggest that it is easier to match the pitch of one's own voice than to match the pitch of a neutral female voice and nonvocal complex tones, although no difference was found for pitch discrimination abilities. One possible implication of this study is that differences in matching the pitch of one's own voice compared to matching other stimuli types may help to differentiate the source of singing inaccuracy (motor vs discrimination skills).

TABLE 1 . Frequency Pairs of the Pitch Discrimination Test Stimulus in Hz 
TABLE 2 . Pitch Production Test Stimuli and Frequencies of Screech Stimuli (Hz) 
TABLE 3 . Pitch Discrimination and Pitch Production Accuracy Accuracy Within 
TABLE 5 . Participants Who Discriminated Pitches Inaccurately and Produced Pitches Inaccurately Participant Discrimination Production at Semitone level 
Pitch Discrimination and Pitch Matching Abilities of Adults who Sing Inaccurately

October 2005


1,177 Reads

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.

Abnormal soft palate posturing in patients with laryngeal movement disorders

January 1997


24 Reads

Laryngeal movement disorders (LMDs), including spasmodic dysphonia and essential voice tremor, have been described as focal disorders affecting the muscles of the larynx. Little reference has been made to possible hyperfunction of supralaryngeal structures and/or palatal involvement. Videonasolaryngoscopic examinations of 83 patients with LMDs revealed a significantly high incidence of abnormal soft palate posturing (84%). Further associations and implications are presented.

The Value of Laryngeal Electromyography in the Evaluation of Laryngeal Motion Abnormalities

October 2006


37 Reads

Laryngeal electromyography (EMG) functions routinely as a prognostic tool in the evaluation of vocal fold paralysis, as a guide for therapeutic injections into the laryngeal muscles, and more recently as an assessment tool in the evaluation of vocal fold paresis. This study investigates the clinical utility of laryngeal EMG as a diagnostic aid in the evaluation of movement disorders of the larynx in patients complaining of dysphonia. A retrospective chart review of all laryngeal EMGs performed at a tertiary laryngology referral center over a 13-month period was performed. All laryngeal EMGs were performed to evaluate laryngeal motion abnormalities in dysphonic patients. Thirty-seven laryngeal EMGs were completed during this study period. Analysis of the data revealed that the medical treatment plan changed as a result of findings on laryngeal EMG in 10/37 patients (27.0%); laryngeal EMG guided and/or confirmed the course of treatment in 12/37 patients (32.4%) and did not change the treatment plan in 15/37 patients (40.5%). Laryngeal EMG is a useful diagnostic tool that, in this study, contributed significantly to and helped guide the evaluation and management of motion disorders in the larynx of dysphonic patients.

An Exploration of Skin Acceleration Level as a Measure of Phonatory Function in Singing

February 2008


72 Reads

Two kinds of fluctuations are observed in phonetogram recordings of singing. Sound pressure level (SPL) can vary due to vibrato and also due to the effect of open and closed vowels. Since vowel variation is mostly a consequence of vocal tract modification and is not directly related to phonatory function, it could be helpful to suppress such variation when studying phonation. Skin acceleration level (SAL), measured at the jugular notch and on the sternum, might be less influenced by effects of the vocal tract. It is explored in this study as an alternative measure to SPL. Five female singers sang vowel series on selected pitches and in different tasks. Recorded data were used to investigate two null hypotheses: (1) SPL and SAL are equally influenced by vowel variation and (2) SPL and SAL are equally correlated to subglottal pressure (P(S)). Interestingly, the vowel variation effect was small in both SPL and SAL. Furthermore, in comparison to SPL, SAL correlated weakly to P(S). SAL exhibited practically no dependence on fundamental frequency, rather, its major determinant was the musical dynamic. This results in a non-sloping, square-like phonetogram contour. These outcomes show that SAL potentially can facilitate phonetographic analysis of the singing voice.

Acoustic analysis of functional dysphonia: Before and after voice therapy (accent method)

July 1994


128 Reads

Ten patients who were referred to a speech pathologist for functional voice disorders were treated with voice therapy using the accent method. The vocal folds were normal except in three females who had moderate bilateral nodules. The voices were analyzed acoustically before and after treatment. Of the parameters tested, pitch perturbation quotient, amplitude perturbation quotient, normalized noise energy for 1-4 kHz, and fundamental frequency showed significant improvement.

The accent method of voice therapy: Effect of accentuations on FO, SPL, and airflow

January 1994


158 Reads

The effect of the increased flow rate (delta U) in response to the Accent Method exercises on fundamental frequency (FO) and sound pressure level (SPL) was studied in three subjects (professionally trained, trained, and untrained in this method). In all the subjects, the rhythmic accentuated exercises produced a variable degree of increase in FO (delta FO) and SPL (delta SPL). The professionally trained subject showed greater delta FO and delta SPL in response to the delta U in the fastest tempo, which requires higher skills. Both trained subjects showed a greater correlation between delta U and both delta SPL and delta FO, as well as between delta FO and delta SPL, as compared to the untrained subject. The effects of the accentuated exercises on FO and SPL in response to the increased airflow rate (delta U) thus appear to demonstrate the treating effectiveness of the Accent Method.

Scaling of Voice Pleasantness and Acceptability in Tracheoesophageal Speakers

October 2005


25 Reads

The purpose of this study was (1) to determine the psychophysical character of auditory-perceptual ratings of voice pleasantness (VP) and voice acceptability (VA) for tracheoesophageal (TE) speakers using direct magnitude estimation (DME) and equal-appearing interval (EAI) scaling procedures and (2) to determine the relationship between listeners' ratings of VP and VA. Ten adult listeners judged overall VP and VA from connected speech samples produced by 20 adult male TE speakers. Although results yielded a prothetic continuum for VP and a metathetic continuum for VA, the amount of variance accounted for by a curvilinear model of VP was minimally more than that accounted for by a linear model. Results also revealed a significant relationship between VP and VA (r = 0.939). Findings from this study do not suggest any greater validity associated with VP and VA ratings obtained by the DME than the EAI method. As a result of the significant relationship between these ratings and to the ease of applying EAI scales, it is recommended that VA be used as a current clinical outcome measure. These data illustrate the need to identify attributes that best describe TE speech that are measured appropriately and are clinically useful.

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