阻塞性睡眠呼吸暂停低通气综合征对嗓音质量的影响

目的　探讨阻塞性睡眠呼吸暂停低通气综合征（OSAHS）对嗓音质量的影响。方法　运行Dr.Speech声学参数分析软件,采用电声门图检测方法对82例OSAHS患者及53例健康人电声门图信号的基频微扰、振幅微扰、标准化噪声能量、接触率微扰、接触幂微扰、声带振动及电声门图波形进行测试分析。结果　正常发声时,22例轻度OSAHS患者电声门图信号的基频微扰、振幅微扰、标准化噪声能量、接触率微扰、接触幂微扰分别为（1.037±1.493）%、（5.627±1.872）%、（-16.109±1.719）dB、（2.638±0.633）%、（166.789±30.492）% ;24例中度OSAHS患者各项指标分别为（1.578±0.362）%、（8.478±1.635）%、（-11.517±1.614）dB、（6.043±0.936）%、（255.210±91.224）%;36例重度OSAHS患者各项指标分别为（2.138±1.384）%、（14.888±4.089）%、（-7.677±2.151）dB、（11.749±7.164）%、（431.233±259.266）%,均明显高于53例对照组（0.517±0.303）%、（3.299±2.196）%、（- 2 1 . 9 3 3±5 . 4 7 7）d B、（1 . 3 2 2±0 . 9 4 2）%、（58.834±131.849）%,差异均有统计学意义。全部OSAHS患者的声带振动规律性均严重失常,电声门图波形不规律。结论　OSAHS患者上呼吸道结构改变,引起非生理性呼吸,声带黏膜干燥,弹性减弱,电声门图声学指标升高,振动严重失常,应对OSAHS患者的嗓音质量予以关注,尽早治疗。     

A comparison of selected phonatory behaviors of healthy aged and young adults.

Selected phonatory behaviors of healthy aged and young men and women were compared. Inverse-filtered air flow, electroglottograph (EGG), and intraoral air pressure signals were recorded as subjects phonated in each of four conditions: normal, soft, loud, loud/high pitched. Minimum flow offset, flow amplitude, air flow duty cycle, EGG duty cycle, estimated subglottal pressure, and fundamental frequency were derived from the recorded signals and compared among age/gender groups. Males had significantly greater flow amplitude than females regardless of age. Significant Age x Sex interactions were found for fundamental frequency and duty cycle measures. Duty cycles and fundamental frequency increased for males and decreased for females with aging. For the normal phonatory condition, aged men had significantly greater duty cycle measures, flow amplitude, and estimated subglottal pressure than young men. There were significant differences in fundamental frequency and EGG duty cycle between aged and young women during normal phonation. It was concluded that the effects of aging on phonatory behaviors are different in degree and kind for men and women. Fewer significant age-related differences in phonatory measures for women than men were consistent with reports of less age-related laryngeal degeneration in females than males.     

Electroglottographic evaluation of gender and vowel effects during modal and vocal fry phonation.

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 (F0) between women and men. The present study tested the hypothesis that significant differences in glottal cycle 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 F0, duration of opening and closing phase, and contact symmetry (speed quotient) were derived from 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.     

电声门图与声学测试技术在病理性嗓音诊断中的运用

目的：探讨电声门图(EGG)和声学测试参数值与嗓音疾病诊断的相关性。方法：采用EGG及声学测试两种检测方法对207例正常人和296例喉部疾病患者进行测试。运用Dr．Speech 3．0软件，计算出嗓音声学分析参数，并对数据进行统计学分析。结果：声带息肉和声带小结患者的振幅微扰(shimmer)和频率微扰(jitter)变化率相近，但shimmer的敏感度较jitter更高。声带息肉、声带小结、喉鳞状细胞癌与对照组相比，习惯基频、jitter和shimmer增大，谐噪比减小。喉鳞状细胞癌患者接触幂值高于对照组，接触率与之比较差异无统计学意义。结论：EGG和声学测试参数值及波形的变化可为喉部疾病的诊断提供客观的量化指标。     

Effect of superior laryngeal nerve stimulation on phonation in an in vivo canine model

We investigated the effect of variation in superior laryngeal nerve stimulation (SLNS) on vocal fold vibration. Photoglottography (PGG), electroglottography (EGG), and subglottic pressure (Psub) were measured in seven mongrel dogs using an in vivo canine model of phonation. The PGG, EGG, and Psub signals were examined at three SLNS frequencies (100 Hz, 130 Hz, and 160 Hz) using a constant rate of air flow. Increasing SLNS, which causes a contraction of the cricothyroid muscle, produced a marked increase in Fo, little change in Psub, an increase in the open quotient, and a decrease in the closed quotient of the glottal cycle.     

Vocal efficiency measurements in subjects with vocal polyps and nodules: a preliminary report

Vocal efficiency is a quantitative measure of the ability of the larynx to convert subglottal power to acoustic power. On the basis of the scant previous literature and clinical intuition, we tested the hypothesis that vocal efficiency, as an indicator of the functional status of the larynx, is abnormally reduced in persons with vocal nodules and polyps. Because the most difficult aspect of obtaining measures of vocal efficiency has been the determination of subglottal pressure, we applied a noninvasive airflow interruption technique for this purpose. Subjects with normal voices (n = 22), vocal polyps (n = 14), and vocal nodules (n = 16) phonated at different intensities into a mask connected by way of piping to a flow meter, a pressure transducer, and an acoustic microphone. Inflation of a balloon-type valve located within the piping provided interruption of phonation. The intraoral pressure plateau occurring during flow interruption was used to estimate subglottal pressure. Subglottal power and acoustic power were determined, and their quotient provided a measure of vocal efficiency. The vocal efficiency in the normal subjects averaged 1.15 x 10(-5) at 70 dB, 3.17 x 10(-5) at 75 dB, 7.52 x 10(-5) at 80 dB, and 1.41 x 10(-4) at 85 dB. The vocal efficiency in the patients with vocal polyps averaged 3.62 x 10(-6) at 70 dB, 8.34 x 10(-6) at 75 dB, 2.10 x 10(-5) at 80 dB, and 4.26 x 10(-5) at 85 dB. The vocal efficiency in the patients with vocal nodules averaged 4.32 x 10(-6) at 70 dB, 1.57 x 10(-5) at 75 dB, 4.26 x 10(-5) at 80 dB, and 8.34 x 10(-5) at 85 dB. As compared to the normal subjects, the patients with laryngeal polyps or vocal nodules had significantly reduced vocal efficiency. These results provide quantitative verification of the clinical impression of inefficient phonation in patients with mass lesions of the vocal folds.     

Effectiveness of the Computed Analysis of Electroglottographic Signals in Muscle Tension Dysphonia

Objective: To investigate the usefulness of electroglottography (EGG) parameters in the diagnosis and estimation of efficacy of voice therapy for muscle tension dysphonia (MTD). Patients and Methods: Nineteen MTD participants, an equivalent number of dysphonic ('organic') patients with vocal fold lesions and as many normal speakers were enrolled. Acoustic (Ac) and EGG signals during sustained phonation were recorded simultaneously. The period and amplitude perturbation quotient of both signals, the closed quotient (CQ) of EGG signals (mean CQ) and its standard deviation (CQSD) were calculated, and subsequently compared among the three groups. These parameters in the MTD group were compared before and after voice therapy. Results: The perturbation measures of both signals in the MTD group were either as high as or significantly higher than those in the organic group or the control group, respectively. Both the Ac and EGG parameters after therapy significantly decreased. The CQSD, but not mean CQ, also decreased after therapy. Conclusion: EGG parameters related to the regularity of vocal fold vibration, but not to the degree of vocal fold contact (mean CQ), are useful for the diagnosis and estimation of voice therapy outcome in MTD.     

Use of the 'real-ear to dial difference' to derive real-ear SPL from hearing level obtained with insert earphones

The electroacoustic characteristics of a hearing instrument are normally selected for individuals using data obtained during audiological assessment. The precise inter-relationship between the electroacoustic and audiometric variables is most readily appreciated when they have been measured at the same reference point, such as the tympanic membrane. However, it is not always possible to obtain the real-ear sound pressure level (SPL) directly if this is below the noise floor of the probe-tube microphone system or if the subject is unco-operative. The real-ear SPL may be derived by adding the subject's real-ear to dial difference (REDD) acoustic transform to the audiometer dial setting. The aim of the present study was to confirm the validity of the Audioscan RM500 to measure the REDD with the ER-3A insert earphone. A probe-tube microphone was used to measure the real-ear SPL and REDD from the right ears of 16 adult subjects ranging in age from 22 to 41 years (mean age 27 years). Measurements were made from 0.25 kHz to 6 kHz at a dial setting of 70 dB with an ER-3A insert earphone and two earmould configurations: the EAR-LINK foam ear-tip and the subjects' customized skeleton earmoulds. Mean REDD varied as a function of frequency but was typically approximately 12 dB with a standard deviation (SD) of +/- 1.7 dB and +/- 2.7 dB for the foam ear-tip and customized earmould, respectively. The mean test-retest difference of the REDD varied with frequency but was typically 0.5 dB (SD 1 dB). Over the frequency range 0.5-4 kHz, the derived values were found to be within 5 dB of the measured values in 95% of subjects when using the EAR-LINK foam ear-tip and within 4 dB when using the skeleton earmould. The individually measured REDD transform can be used in clinical practice to derive a valid estimate of real-ear SPL when it has not been possible to measure this directly.     

Contralateral suppression of distortion product otoacoustic emissions: effect of the primary frequency in Dpgrams

The amplitude of the 2f1-f2 distortion product otoacoustic emission (DPOAE) can be suppressed by presenting contralateral acoustic stimulation. To test the hypothesis that DPOAE contralateral suppression is influenced by the primary frequency in DPgrams, DPgrams were recorded at resolutions of 1, 8, and 17 pts/octave, in the absence and presence of contralateral broadband noise (BBN). Participants were 20 normal-hearing human adults. In DPgrams with higher frequency resolutions, DPOAE suppression at amplitude peaks in DPgrams (8 pts/octave: Mean = - 0.92 dB, SD = 0.71 for BBN at 60 dB SPL; 17 pts/octave: Mean = - 0.25 to -1.44 dB, SD = 0.51 to 0.86 for BBN at 40 to 70 dB SPL, respectively) was larger than the suppression at the dips in DPgrams (8 pts/octave: Mean = - 0.13 dB, SD = 1.00; 17 pts/octave: Mean = - 0.03 to -0.73 dB, SD = 0.55 to 0.91). A larger intersubject variability in DPOAE contralateral suppression was observed at the dips. The results suggest that measuring DPOAE contralateral suppression at the primary frequencies corresponding to the peaks in DPgrams with higher frequency resolutions may improve the assessment of the efferent system function.     

声带振动功能的定量检测

目的：探讨声带振动功能的定量检测技术及其影响因素。方法：应用计算机软件,分析６０例正常人动态喉镜图像和电声门图参数,结合性别、频率和声强,进行统计分析。结果：声带振动周期中发声频率增加伴随开放相相对延长（ＣＱ减小,ＯＱ增大）,而声强增加则开放相相对缩短,且渐闭相缩短更明显（ＯＱ减小,ＳＱ增大）,男性较女性声门闭合相长（ＯＱ小）。发声时声带闭合的速度大于开放的速度（ＣＶ〈ＯＶ,ＣＣＰ〈ＣＯＰ）。结论     

Calculating the Hearing Threshold from the Stapedius Reflex Threshold for Different Sound Stimuli

The acoustic stapedius reflex depends not only on stimulus intensity, but also on stimulus frequency, as far as reflex threshold, amplitude of response and reflex decay are concerned. The stapedius reflex threshold (SRT) for wide-band noise has been proved lower than that for pure tones. Our own investigations dealt with the relation between the SRTs for pure tones, white noise, and a 24-tone mixture (one single tone at every critical band width) in normal-hearing persons and patients suffering from sensorineural hearing loss

In normal hearing, the SRT for pure tones was measures at 70-85 dB (73-105 dB SPL) above the normal-hearing threshold in a free sound-field, the SRT for white noise (average) at 46.5 dB (68.5 dB SPL) and the SRT for the 24-tone mixture at 47.0 dB (67.2 dB SPL). In 125 patients (223 ears), the difference level between the mean SRT for tones of 0.5-4 kHz and the SRT for white noise (dl 2) was correlated with the difference level between the mean SRT for tones of 0.5-4 kHz and the mean hearing threshold for tones of 0.5-4 kHz (dl 1). The functions were found to be roughly linear: dl 2 = dl 1/2.5 and dl 1 = 2.5 dl 2. Validity: 73% ～ 10 dB; 17% ～ 15 dB, and 10% ～ 20 dB. Since the dB-value of the mean SRT for pure tones of 0.5-4 kHz can be read from the audiogram, it is possible to calculate the mean hearing threshold for 0.5-4 kHz from dl 2 with equal validity: mean hearing threshold 0.5-4 kHz = SRT tones -2.5 dl 2

In cases of falling threshold curves the results become less exact and in addition to the SRT for white noise and pure tones, the SRT for two tone-mixtures was determined, namely for one low-pass noise consisting of 12 sine waves of 100-1 600 Hz, and for one high-pass noise consisting of 12 sine waves of 1.8-13.5 kHz. In normal hearing, the dl 2 for the low-pass noise is ～ 15 dB and for the high-pass noise ～ 20 dB (3:4). In falling audiograms, the dl 2 for the high-pass noise was found to be equal or lower than that for the low-pass noise. Investigations in sleeping children indicated that these relations were practically unchanged

A correlation of the free-field findings with the loudness calculated by Zwicker's procedure showed that the triggering of the stapedius reflex by wide-band sounds is due to the centrally summated loudness and not the SPL     

High-speed digital imaging and electroglottography of tracheoesophageal phonation by Amatsu's method

Background. Our previous findings have indicated that the thyropharyngeal muscles form a retropharyngeal prominence during alaryngeal phonation via the TE fistula. This prominence forms a so-called ‘neoglottis’, which is thought to function as the vibratory source. To better understand the mechanism of TE phonation, we analyzed the vibration of the neoglottis using electroglottography (EGG) and a high-speed digital imaging system. Patients and methods. Two volunteers who use TE phonation for their daily speech communication were subjected to this study. The vibrations of the neoglottis were recorded simultaneously as EGG and high-speed imaging with acoustic signals. Results. The vibrations of the neoglottis, recorded by means of high-speed digital imaging, were exactly synchronized with the waveforms of the acoustic signals and EGG. Conclusions. These results further confirm the neoglottis as the source of vibration during tracheoesophageal (TE) phonation.     

Usefulness of electroglottogram (EGG) and photoglottogram (PGG) for the analysis or vocal fold vibration--a high speed digital imaging study

Simultaneous recordings of EGG, PGG and high-speed digital imaging (HSDI) of vocal fold vibration were made in 3 normal male subjects and the results were compared to evaluate the usefulness of EGG and PGG for the analysis of the vibratory pattern. Each subject was required to produce sounds of 3 different pitches at 3 different intensity levels in the recording sessions and the 27 sets of data samples were collected. For each data set, the glottal area waveform (GAW), glottal width waveform (GWW), EGG, differentiated EGG, PGG, differentiated PGG, and voice waveform were displayed in a graphic form on the same time axis and their patterns were compared. Based on the analysis of GAW and GWW, it was found that there were variations in the pattern of closing and opening of the vocal fold margin corresponding to the differences in the type of phonation. The EGG waveform appeared to correspond well to that of the movement of the vocal fold margin in the closing phase, while the correspondency was less apparent in the opening phase. It is considered that the EGG waveform is dependent on the mode of contact between the two vocal folds and that a careful observation of the EGG is useful and practical for predicting the pattern of vocal fold vibration. On the other hand, it was difficult to determine the onset of the closing and opening phases only from PGG waveform and there was a timing difference between the PGG and GAW. Although PGG seemed to be useful for judging the presence or absence of the opening phase and for the pitch measurement, it is considered to be unsuitable for a precise cycle-by-cycle analysis of the pattern of vocal fold vibration.     

Subtotal carbon dioxide laser arytenoidectomy for the treatment of bilateral vocal fold immobility: long-term results

Sixty-nine patients underwent subtotal carbon dioxide laser arytenoidectomy for treatment of bilateral vocal fold immobility between 1985 and 2000. The population included 69 patients whose mean age was 56 years (SD, 16 years; range, 11 to 82 years). The mean follow-up was 50 months (SD, 44 months; range, 1 to 181 months). The overall postoperative peak expiratory/peak inspiratory flow ratio (normal value, 1) significantly improved (closer to 1; p = .0036). Voice analyses were also undertaken for 27 patients, almost exclusively after operation, given the context of initial emergency. The maximum phonation time averaged 6.57 seconds (median, 6 seconds). The phonation quotient remained high, with a mean of 503 (median, 440), and the mean conversational voice intensity remained around 59 dB. The median frequency analysis type was 3. The advantage of subtotal arytenoidectomy lies in the fact that it maintains a certain degree of rigidity along the posterior limit of the arytenoid frame, preventing inward collapse of the mucosa and thus lowering the risk of aspiration.     

The effect of recurrent laryngeal nerve stimulation on phonation in an in vivo canine model

The present investigation was designed to examine the effect of variation in recurrent laryngeal nerve stimulation (RLNS) on vocal fold vibration. Photoglottography (PGG), electroglottography (EGG), and subglottic pressure (Psub) were measured in seven mongrel dogs using an in vivo canine model of phonation. The PGG, EGG, and Psub signals were examined at three fundamental frequencies (F0) (100 Hz, 130 Hz, and 160 Hz) for RLNS, using a constant rate of air flow. Increasing RLNS, which caused activation of the intrinsic laryngeal muscles, produced a modest increase in F0, a marked increase in Psub, no change in the open quotient (OQ), and an increase in the closing quotient (CQ). Phase quotient (Qp), which describes the interval between opening of the lower and upper fold margins, decreased with increasing RLNS.     

Contralateral suppression of distortion product otoacoustic emissions: Effect of the primary frequency in Dpgrams

The amplitude of the 2f1–f2 distortion product otoacoustic emission (DPOAE) can be suppressed by presenting contralateral acoustic stimulation. To test the hypothesis that DPOAE contralateral suppression is influenced by the primary frequency in DPgrams, DPgrams were recorded at resolutions of 1, 8, and 17 pts/octave, in the absence and presence of contralateral broadband noise (BBN). Participants were 20 normal-hearing human adults. In DPgrams with higher frequency resolutions, DPOAE suppression at amplitude peaks in DPgrams (8 pts/octave: Mean = ? 0.92 dB, SD = 0.71 for BBN at 60 dB SPL; 17 pts/octave: Mean = ? 0.25 to ?1.44 dB, SD = 0.51 to 0.86 for BBN at 40 to 70 dB SPL, respectively) was larger than the suppression at the dips in DPgrams (8 pts/octave: Mean = ? 0.13 dB, SD = 1.00; 17 pts/octave: Mean = ? 0.03 to ?0.73 dB, SD = 0.55 to 0.91). A larger intersubject variability in DPOAE contralateral suppression was observed at the dips. The results suggest that measuring DPOAE contralateral suppression at the primary frequencies corresponding to the peaks in DPgrams with higher frequency resolutions may improve the assessment of the efferent system function.     

Electroglottography in the pediatric population.

OBJECTIVE: To establish normative electroglottography (EGG) data in the pediatric population. DESIGN: Clinical study with EGG data gathered on children with normal voices. SETTING: Major children's hospital and specialty eye and ear hospital. PATIENTS: A total of 164 children, 79 girls and 85 boys, aged 3 to 16 years. METHODS: Children with normal voices, determined through subjective evaluation and a voice use history questionnaire, underwent EGG recording. The EGG data were analyzed with commercially available software for fundamental frequency, jitter, open quotient, closing quotient, and opening quotient. RESULTS: Normative EGG data were established for children aged 3 to 16 years. Jitter, open quotient, closing quotient, and opening quotient were all found to have no significant dependence on age. CONCLUSIONS: Children as young as 3 years can easily tolerate EGG, making it possible to establish this initial set of normative pediatric EGG data. These preliminary results suggest that EGG may have potential to assist clinicians with noninvasive documentation of vocal function in the pediatric population. This maybe particularly important for tracking treatment-related changes in the vocal function of children who are difficult to examine endoscopically.     

Protection against acoustic trauma by forward and backward sound conditioning

The purpose of the present study was to determine if short-term sound conditioning provides protection when delivered either before (forward sound conditioning) or after (backward sound conditioning) a traumatic exposure in the guinea pig. Two different sound conditioning paradigms were studied (1 kHz, 81 dB SPL, 24 h; 6.3 kHz, 78 dB SPL, 24 h). The 1-kHz forward sound conditioning paradigm (81 dB SPL, 24 h) protected distortion product otoacoustic emissions (DPOAEs) against a short-duration acoustic trauma (2.7 kHz, 103 dB SPL, 5 min) compared to the group exposed to the acoustic trauma alone. The 1-kHz forward sound conditioning paradigm (81 dB SPL, 24 h) also protected both the auditory brainstem response (ABR) thresholds and DPOAEs against a longer-duration acoustic trauma (2.7 kHz, 103 dB SPL, 30 min). The group exposed to the acoustic trauma alone showed ABR threshold shifts between 15 and 24 dB, and DPOAE amplitude shifts between 11 and 24 dB, while the group with 1-kHz forward sound conditioning showed statistically significant protection at all ABR frequencies and at all DPOAE frequencies. The 1-kHz backward sound conditioning paradigm protected against acoustic trauma (2.7 kHz, 103 dB SPL, 30 min). The ABR thresholds were protected at 1, 2 and 4 kHz, and DPOAEs at all frequencies (except 8 kHz) when compared to the group exposed only to the acoustic trauma. The 6.3-kHz forward sound conditioning paradigm protected against acoustic trauma (5.5 kHz, 109 dB SPL, 30 min) at 6.3, 8 and 10 kHz. The 6.3-kHz backward sound conditioning paradigm showed no protection against acoustic trauma at any DPOAE frequency. Taken together, these findings are important for understanding how the auditory system can be modulated by acoustic stimulation and highlights the importance of the acoustic environment during the recovery process of the auditory system.     

Activation of tyrosine hydroxylase in the lateral efferent terminals by sound conditioning

Preconditioning to sound is a well-documented strategy to provide protections against a subsequent acoustic trauma. In the present study, preconditioning (1.0 kHz tone at 81 dB sound pressure level (SPL) for 24 h) protected ABR thresholds by 17-28 dB from an acoustic trauma (2.7 kHz, 103 dB SPL, 30 min) that resulted in a temporary threshold shift. The protection afforded by sound conditioning was shown to be blocked by the administration of 6-hydroxydopamine which disrupts tyrosine hydroxylase in the nerve terminals of the lateral efferent fibers. Furthermore, tyrosine hydroxylase immunoreactivity was up-regulated both by sound conditioning alone, and by the combined treatment of sound conditioning and acoustic trauma. In contrast, acoustic trauma alone resulted in a reduction in tyrosine hydroxylase immunoreactivity compared to unexposed controls. These findings are the first demonstration that tyrosine hydroxylase in the lateral efferents are up-regulated during sound conditioning and suggests a role for the lateral efferent system in protecting against acoustic trauma by sound conditioning.     

Phonation threshold pressure measurements during phonation by airflow interruption

OBJECTIVE/HYPOTHESIS: Most methods to measure phonation threshold pressure (PTP) are clinically impractical because they are invasive. This report concerns an airflow interruption system developed to allow noninvasive estimation of (PTP) at different levels of vocal intensity. An estimation of PTP was made for normal subjects with normal larynges and no voice complaints and for individuals who had dysphonia associated with vocal polyps to compare the estimated minimal pressure across the glottis that was required to sustain phonation in the two conditions. STUDY DESIGN: This was a methodological study designed to measure an unanticipated PTP from a subject. METHODS: Subjects sustained a constant tone and the airflow was directed into a section of pipe with an airtight mask over the mouth and nose. The airflow, intramask pressure, and intensity of the acoustic output were recorded. A PTP was predicted from a difference between an estimate of the subglottal pressure and the vocal tract pressure at the point that phonation ceased after interruption of airflow. Eleven control subjects and 13 patients with vocal fold polyps were studied. In each population there were eight men and five women. The individuals in the group with vocal fold polyps averaged 39 years of age, and the control subject group averaged 49 years of age. Normal subjects produced a steady vowel /a/ at 75, 80, and 85 dB. Patients with polyps were unable to sustain phonation at these levels but were able to produce phonation at 65, 70, and 75 dB. The validity of the system was tested using a laryngeal model and in a patient with a normal larynx and voice who had a tracheotomy (placed for sleep apnea syndrome) which allowed direct measurement of subglottal pressure. RESULTS: The measured mean PTP levels (with standard deviation [SD]) for the control subjects were 2.38 (1.273), 2.67 (1.879), and 2.98 (2.23) cm H2O at 75, 80, and 85 dB, respectively. The measured mean PTP levels (with SD) for the patients with polyps were 4.79 (2.67), 5.85 (2.34), and 7.37 (3.26) cm H2O at 75, 80, and 85 dB, respectively. The differences in mean PTP between groups at 75, 80, and 85 dB were significant at P = .013, P = .017, and P = .010, respectively. CONCLUSIONS: The estimations of PTP for patients with vocal fold polyps were significantly higher than for the control subjects at three phonation levels.