Electroglottographic Parameters Research Articles

Evaluation of Immediate Effects of Straw Phonation Exercise and Determination of the Ideal Performance Time in Healthy Adults

The ideal performance time of straw phonation exercise, one of the semi-occluded vocal tract exercise types, in which optimal effects are seen in healthy voices is still unknown. The aim of this study was to investigate the immediate effect of straw phonation exercise in healthy adults after 1, 3, 5, 7, and 10 minutes, considering: acoustic parameters, electroglottographic parameters, auditory-perceptual general voice quality, the participants' self-assessment regarding vocal effort, and laryngeal discomfort during exercise. This study included 69 participants (35 women, 34 men) with a healthy voice. Participants performed the exercise with straw for a total of 10 minutes. The data were collected before (m0) and immediately after exercises at the first (m1), third (m3), fifth (m5), seventh (m7), and tenth (m10) minutes of performance using sustained emission of vowel /a/ and a sentence. There was an increase in the fundamental frequency at m7 and a decrease in the shimmer from m5 in men. The sound pressure level increased at m5 and m10 in women and from m1 in men. The Acoustic Voice Quality Index score decreased at m5 in men. The mean average closed quotient decreased at m10 in women. Auditory-perceptual general voice quality was optimal at m3 in women and at m5 in men, it deteriorated at m7 in women and at m10 in men. The vocal effort during the exercise increased at m7 in women and at m10 in men. The laryngeal discomfort during the exercise increased for both sexes at m10. The straw phonation exercise in healthy individuals promoted optimal effects on voice quality after 5 and 7 minutes for men and 3 and 5 minutes for women. Prolongation of the exercise time causes negative effects on voice quality and an increase in vocal effort and laryngeal discomfort presented by the participants.

The Immediate and Long-Term Effects of Tube and Mask+Tube Phonation in Water Exercises and Their Duration as Measured by Electroglottographic and Nasometric Parameters

This study investigated the immediate effects and their persistence (at 15 minutes) of various durations of semi-occluded vocal tract exercise (SOVTE) (standard tube into water and modified mask+tube into water exercises) as measured by electroglottographic (EGG) and nasometric parameters. The study included 30 women aged 19 through 28 years with healthy voices, and it comprised five randomly implemented procedures (Ps): P1-tube phonation into water for 5 minutes; P2-tube phonation into water for 10 minutes; P3-tube+ventilation mask phonation into water for 5 minutes; P4-tube+ventilation mask phonation into water for 10 minutes; P5-phonation with ventilation mask for 5 minutes. Fifteen-minute voice rest breaks were provided between each procedure. Nasometric and electroglottographic measurements were taken before, during, immediately after and at 5, 10, and 15 minutes after the exercises, and the recorded measurements were analyzed. The immediate effects of P3 and P4 on voice quality showed better performance than the other procedures. Among all the procedures, P1 had the smallest effect on voice quality in terms of nasometric and EGG parameters and the least degree of effect permanence. In all the fluctuating SOVTE procedures except P1, the nasalance scores decreased (P1, P2, P3, and P4: fluctuating SOVTE; P5: steady SOVTE). The tube phonation exercises modified by the addition of a ventilation mask were highly advantageous in terms of EGG parameters. In addition to this, regardless of the mode of application of the retention time, it was observed that the positive effect (ie, lower vertical laryngeal position) of the exercises applied for 10 minutes was higher than the exercises applied for 5 minutes.

Effect of Varied Tube Phonation in Water Exercises on Nasometric and Electroglottographic parameters: Modification in Terms of Fluid Density and Tube Submerged Depth

Within the scope of semi-occluded vocal tract exercises (SOVTEs), we aimed to examine the effects of four exercise combinations, which involved various fluid densities and tube submersion depths, on acoustic and electroglottographic (EGG) parameters. Four procedures (P) were applied consecutively to 30 female participants with normal voices using different tube submersion depths and fluid densities, including P1 (2 cm, water), P2 (2 cm, nectar), P3 (10 cm, water), and P4 (10 cm, nectar). Nasometric (Nasometer II model 6450) and EGG (Electroglottograph model 6103) measurements were taken before the procedures were initiated (pre-test) and at the end of each procedure. In addition, EGG measurements were taken for each procedure during the application. For all three velar positions (oral passage, oro-nasal passage, nasal passage), the only procedure that caused a significant change compared to the pre-test stage in regard to nasalance score was P2 (2 cm nectar) in common. All other procedures except P1 (2 cm water) significantly increased velar closure compared to pre-test levels. However, when the differences between the exercises were examined, the least velar closure, compared to the other procedures, was obtained after P4 (10 cm nectar). While there was no significant difference between the procedures in the EGG measurements during the exercise, a significantly higher tendency to contact was observed after the procedures with a denser consistency, and an increase in the fundamental frequency (fo) values occurred in the pairwise comparisons of the procedures in the measurements after the exercises. In SOVTEs in which water phonation is performed with a tube, the use of a fluid with a consistency denser than water can be considered a particularly promising approach. In addition, exercises performed with increasing consistencies in 2 cm depth can provide more vocal cord and velopharyngeal port closure by increasing EGG-CQ and nasalance score values. However, more care should be taken while increasing the consistency at a submersion depth of 10 cm.

Receiver operating characteristic analysis of acoustic and electroglottographic parameters with different sustained vowels

Objective To examine the power of the parameters obtained from different sustained vowels used in acoustic and electroglottographic (EGG) voice evaluation protocols to discriminate between dysphonic and non-dysphonic voice quality. Methods Sixty non-dysphonic participants and 30 dysphonic participants were included in the study. In addition to the time domain amplitude and frequency perturbation parameters obtained from the sustained phonation of /ʌ/-/ɛ/-/i/-/u/ vowels, several frequency-domain spectral/cepstral parameters and EGG parameters were evaluated. The classification performance of the acoustic and electroglottographic measures was quantified using analysis and receiver operating characteristic (ROC) curve analysis. Results As a result of ROC analysis, the discriminative diagnostic performance (area under the curve, AUC) of the test for low-vowel (/ʌ/-/ɛ/) phonation was higher than values obtained from high-vowel (/i/-/u/) phonation. For /ʌ/ and /ɛ/ sustained vowels, the parameters exhibiting the highest discrimination were fundamental frequency standard deviation (fo/STD), cepstral peak prominence (CPP), relative average perturbation (RAP), pitch perturbation quotient (PPQ), and jitter percent (JITT). In the EGG parameters, on the other hand, average jitter and periodicity parameters obtained from front vowels (/ɛ/-/i/) were found to have higher AUC values compared to back vowels (/ʌ/-/u/). Conclusions In acoustic analyses, /ʌ/ and /ɛ/ sustained vowels give the highest diagnostic performance. In the electroglottographic evaluation, on the other hand, /ɛ/ and /i/ vowels, when the position of the tongue is forward, have better classification performance compared to /ʌ/ and /u/ vowels, when the position of the tongue is back.

Voice Characteristics of Young Girl Role in Kunqu Opera

Three electroglottographic parameters, fundamental frequency, contact quotient, and speed quotient were analyzed for two singers of Young girl role in Kunqu Opera. Each singer performed three conditions, singing, stage speech, and reading lyrics. The phonation types adopted in different conditions were explored based on electroglottographic parameters. Fundamental frequency, contact quotient, and speed quotient showed different distributions among conditions. Five phonation types were used in singing and stage speech, which include (1) breathy voice, (2) modal voice with low degree of posterior glottal adduction, (3) modal voice, (4) falsetto, and (5) falsetto with high degree of posterior glottal adduction. The phonation strategies partly showed differences between singers. Different phonation type collocations were employed in singing and stage speech. The relationship between phonation types and pitch was complex. The phonation types actually used were different from and more complex than those in traditional Kunqu Opera singing theory.

Phonation type in vowels of heritage and native Gujarati speakers

Gujarati, an Indo-Aryan language, contrasts phonation type in vowels: [baɾ] ‘twelve’ and [baɾ] ‘outside’ (Pandit, 1957) and the current study looked at Gujarati vowels using acoustic and electroglottographic (EGG) analyses. The participants were native and heritage Gujarati speakers. Heritage speakers were born in Canada or arrived in Canada before seven years of age and learned Gujarati as their first language. Due to limited access to their first language, such as listening more than speaking the language and using Gujarati exclusively at home, it was expected that there might not be a significant difference between the heritage speakers’ breathy and modal vowel productions. This study determined if the acoustic and EGG parameters that differentiate breathy from modal vowels were the same or different for both speaker groups. Some of the parameters used to distinguish phonation type were H1-H2, H1-A1 ('A1' refers to amplitude of the first formant), harmonic-to-noise ratio, and contact quotient. Measure...

Comparison of parametrization methods of electroglottographic and inverse filtered acoustic speech pressure signals in distinguishing between phonation types

Abstract This study compared for the electroglottographic (EGG) signal how well six earlier presented and two new parameters distinguish between normal, breathy and pressed phonation and how well they correlate with perceptual evaluation. The results were compared with those obtained for nine parameters describing the glottal flow waveform obtained through inverse filtering of the acoustic speech pressure signal. Acoustic and dual-channel EGG signals were recorded for twenty female and twenty male subjects with healthy voices phonating sustained samples of the vowel [a:] in their habitual normal voice and in simulated breathy (hypofunctional) and pressed (hyperfunctional) phonation. The samples were perceptually evaluated by five voice specialists and rated for firmness of phonation. The best examples from 12 females and 12 males were used for the analyses. Few earlier studies have ranked the behavior of this many EGG and glottal flow parameters from this large speech data. Although the parameters differed in their ranking order, contact quotient calculated with a criterion level at 50% both from the EGG and the inverse filtered signal was strong in correlating with perception and in distinguishing phonation types in cases where fundamental frequency and sound pressure level also varied. When this variation was taken into account, the normalized amplitude quotient NAQ still had an effect in predicting voice quality. The results will have applicability in voice training and therapy and in development of machine learning -based classification methods.

Effective Glottal Instant Detection and Electroglottographic Parameter Extraction for Automated Voice Pathology Assessment.

Accurate determination of glottal instants and electroglottographic (EGG) parameters is most important in voice pathology analysis including multiple voice disorders: neurological, functional, and laryngeal diseases. In this paper, we present a new effective method for reliable detection of glottal instants and EGG parameters from an EGG signal composed of voiced and nonvoice segments. In the first stage, we present an adaptive variational mode decomposition based algorithm for suppressing low-frequency artifacts and additive high-frequency noises. Based upon mode center frequency criterion, the proposed method first constructs a candidate EGG feature signal for determination of glottal closure and opening instants. In the second stage, the candidate glottal instants are determined by detecting the positive and negative zerocrossings in normalized candidate EGG feature signal, respectively. Finally, an autocorrelation features based postprocessing algorithm is presented to reject nonglottal instants from the nonspeech production segments. The accuracy and robustness of the method is tested using noise-free and noisy EGG signals. Evaluation results show that the proposed method achieves an average overall accuracy of 95.06%, identification rate of 95.34%, missed rate of 3.60%, and false alarm rate of 0.06% with average absolute identification error of 0.71 ± 0.66ms for an SNR of 15dB. Results demonstrate that the proposed method significantly outperforms the other existing methods under both noise-free and noisy EGG signals.

Correlation of electroglottograph with vocal cord pathology

<p class="abstract"><strong>Background:</strong> Vocal cord disorders are very commonly encountered in ENT Outpatient. Electroglottogram is a non-invasive method for the examination of the vocal fold vibrations. It exerts no influence at all on articulation and production of sound and is cost effective. The aim of the present study was to validate the clinical correlation of electroglottogram in patients presenting with hoarseness of voice<span lang="EN-IN">. </span></p><p class="abstract"><strong>Methods:</strong> 30 patients with history of hoarseness of voice and 30 normals were selected from ENT outpatient and inpatient department over a period of 2 years. All subjects underwent detailed ENT history taking, clinical examination, rigid laryngoscopy and electroglottography and results were documented<span lang="EN-IN">. </span></p><p class="abstract"><strong>Results:</strong> Electroglottography waveforms of various voice disorders like vocal cord nodule, polyp, papilloma and haemangioma showed specific changes like double peak or notch in closing phase of waveform in case of mass lesion over the vocal cords and fuzzy waveform with prolonged closing time in case of vocal cord palsy. Significant difference was noted in certain electroglottographic parameters for phonated vowels /a/, /i/ and /u/ for certain vocal cord disorders<span lang="EN-IN">. </span></p><p class="abstract"><strong>Conclusions:</strong> Electroglottograph helps in diagnosing the pathology related to vocal cords, whether it is mass lesion over the vocal cords or vocal cord palsy but to differentiate in between mass lesions, clinical examination has to be done to confirm the diagnosis<span lang="EN-IN">.</span></p>

Voice outcome following electrical stimulation-supported voice therapy in cases of unilateral vocal fold paralysis

Abstract The current lack of knowledge on the effects of transcutaneous electrical stimulation-supported voice therapy (TESVT) on voice production, coupled with increasing anecdotal reports of TESVT use with voice disorders, prompted this research. The aim of this study was to compare the therapeutic value of conventional voice therapy (CVT) and TESVT on voice outcome in patients with unilateral vocal fold paralysis. The study was conducted on randomly selected 29 patients with unilateral vocal fold paralysis who were candidates for voice therapy attending to the Unit of Phoniatrics, Department of Otorhinolaryngology, Faculty of Medicine, University of Alexandria. The patients were divided into two groups: group I, which included 14 patients who were assigned to CVT, and group II, which included 15 patients who were assigned to TESVT. Each patient was subjected to the following procedures before and after therapy to document glottis closure and voice quality changes: auditory perceptual assessment using the GRBAS scale, the Voice Problem Self-assessment Scale, videostroboscopic examination, and acoustic and aerodynamic analysis of a sample of phonation in addition to electroglottography. TESVT was applied for all participants. Statistically significant changes have been obtained for all measurers. No significant statistical difference was found between CVT and TESVT in patients with vocal fold immobility except for frequency perturbation and some electroglottographic parameters. Transcutaneous electrical stimulation-supported voice therapy is as effective as CVT in improving voice parameters in cases of unilateral vocal fold immobility. Further research is warranted with a larger number of patients to assess the efficacy of electrical stimulation-supported voice therapy in cases of vocal fold immobility and to determine selective criteria for this TESVT approach.

A Measure of the Auditory-perceptual Quality of Strain from Electroglottographic Analysis of Continuous Dysphonic Speech: Application to Adductor Spasmodic Dysphonia

(1) To develop an automated algorithm to analyze electroglottographic (EGG) signal in continuous dysphonic speech, and (2) to identify EGG waveform parameters that correlate with the auditory-perceptual quality of strain in the speech of patients with adductor spasmodic dysphonia (ADSD). Software development with application in a prospective controlled study. EGG was recorded from 12 normal speakers and 12 subjects with ADSD reading excerpts from the Rainbow Passage. Data were processed by a new algorithm developed with the specific goal of analyzing continuous dysphonic speech. The contact quotient, pulse width, a new parameter peak skew, and various contact closing slope quotient and contact opening slope quotient measures were extracted. EGG parameters were compared between normal and ADSD speech. Within the ADSD group, intra-subject comparison was also made between perceptually strained syllables and unstrained syllables. The opening slope quotient SO7525 distinguished strained syllables from unstrained syllables in continuous speech within individual subjects with ADSD. The standard deviations, but not the means, of contact quotient, EGGW50, peak skew, and SO7525 were different between normal and ADSD speakers. The strain-stress pattern in continuous speech can be visualized as color gradients based on the variation of EGG parameter values. EGG parameters may provide a within-subject measure of vocal strain and serve as a marker for treatment response. The addition of EGG to multidimensional assessment may lead to improved characterization of the voice disturbance in ADSD.

Immediate Effects of Humming on Computed Electroglottographic Parameters in Patients With Muscle Tension Dysphonia

To investigate the immediate effects of humming and subsequent um-hum phonation on the computed parameters of electroglottographic (EGG) signals in muscle tension dysphonia (MTD) patients and nondysphonic speakers. We included 21 MTD participants exhibiting both vocal roughness and supraglottic compression, who were able to produce successful humming and um-hum phonation. Twenty nondysphonic participants were selected as controls. Each participant was instructed to perform three phonatory tasks: natural phonation, humming phonation without pitch changes, and subsequent um-hum phonation, that is, humming with a pitch glide up as if agreeing with someone. Acoustic and EGG signals were recorded while the participants performed these tasks. Computed parameters reflecting the irregularities in vocal fold vibrations and the degree of glottal contact were calculated and compared between the tasks. The MTD group showed decreases in both perceptual vocal roughness and acoustic perturbation parameters while performing the tasks. The perturbation parameters of EGG signals and the standard deviation of the contact quotient (CQ) also exhibited significant decreases associated with either of humming or um-hum phonation in both groups. In addition, the CQ exhibited significant increases following humming alone in the MTD group and the combination of humming and um-hum phonation in both groups. These results suggest that the combination of humming without pitch changes and subsequent um-hum phonation have the immediate effect in adjusting the regularity of vocal fold vibration and augmenting the degree of glottal contact in MTD patients as well as nondysphonic speakers, whereas humming alone increases the degree of glottal contact in MTD patients.

EGG and Acoustic Analyses of Different Voice Samples: Comparison between Perceptual Evaluation and Voice Activity and Participation Profile

Objective: This study investigated whether different electroglottographic (EGG) parameters may be used to estimate voice quality and loading related to it, and whether voice quality is related to self-estimation of voice problems and laryngeal status. The effect of sample type was also considered. Methods: EGG and acoustic signals of a sustained vowel [a:] (90 dB_{6 cm}) and text reading during noise exposure were recorded from 93 female kindergarten teachers. Analyses were made from the sustained vowel and vowel [a:] from a stressed word. Contact quotient (CQ) was calculated. Maximum velocity of increase in contact area inferred from derivative (MDEGG) was examined. Fundamental frequency was calculated from the EGG signal. From the acoustic signal sound pressure level (SPL) was computed and pressedness in voice quality was evaluated perceptually. Self-evaluation was made with Voice Activity and Participation Profile (VAPP). Indirect laryngoscopy was also performed. Results: Pressedness in voice correlated with EGG results only for the sustained vowel, and better with MDEGG than CQ values. VAPP and laryngeal evaluation did not correlate with the acoustic or EGG parameters or with perception. Conclusions: MDEGG is worth testing as an indicator of impact stress. Sustained vowel at a controlled SPL is more suitable for voice quality evaluation than a long stressed vowel from connected speech.

Laryngeal movements in stutterers

Background: The etiology of stuttering is a puzzle. Abnormal laryngeal movements have been assumed to be a cause of stuttering by many researchers. We aimed at comparing the laryngeal functions of stutterers using electroglottogram (EGG) and vocal tract functioning using formant frequency analysis. Materials and Methods: We compared the acoustic and electroglottographic parameters in the phonation of stutterers between the age range of 15-25 years and normal subjects matched for age and sex. Results and Discussion: All the electroglottographic parameters of stutterers differed from that of normal speaking subjects which is indicative of difficulty in adjustment of the laryngeal gestures for speech in stutterers. There was no significant difference between the stutterers and non-stutterers in terms of formant frequencies. Similar formant frequencies in stutterers and normal speakers and abnormal electroglottographic parameters are suggestive of abnormal laryngeal movements and normal vocal tract functioning in stutterers.

Objective and Subjective Evaluation of Larynx in Smokers and Nonsmokers: A Comparative Study

The deleterious effects of smoking on laryngeal mucosa are indisputable. Smoking not only causes histologic (microscopic) alterations in the vocal fold epithelium but also affect the acoustic property of voice. The goal of this study was to determine the effects of smoking on the laryngeal structures and phonatory physiology via videostroboscopy, acoustic voice analysis and electroglottography. Cross-sectional and observational study was carried out in Department of ENT, Pt. J. N. M. Medical College, Raipur, in 100 male volunteers (50 smokers and 50 nonsmokers) between the ages of 18 and 60 years with no voice complaints. All subjects were analyzed for detailed history and underwent videostroboscopic, acoustic voice analysis and electroglottographic examination. Videostroboscopic examination results showed significant relationships between smoking and abnormal vocal fold edge, abnormal texture, edema, erythema, abnormal mucosal cover, abnormal phase symmetry and abnormal pliability/stiffness. Voice analysis showed that smoking has a clear effect on some acoustic voice and electroglottographic parameters. The parameters most commonly affected by smoking are fundamental frequency (F0), jitter, shimmer, F0 tremor, normalized noise energy, signal noise ratio, maximum phonation time (MPT), s/z ratio, opening rate and closing rate. The results indicate that smoking has a significant effect on laryngeal structures and phonatory physiology.

The existence of phonatory instability in multiple sclerosis: an acoustic and electroglottographic study

Dysarthria and phonatory symptomatology are often reported by patients suffering from multiple sclerosis (MS), but have been poorly investigated, although related to life quality. The objective of the study was to investigate the phonatory function in MS patients using objective measures. The speech of 64 MS patients and 64 pair-matched controls was recorded and analyzed using electroglottography, a physiological method that measures the electrical conductance during the opening and closing phases of the vibrating vocal folds. Electroglottographic parameters were correlated with clinical and MRI features. Most of the variables that have been used for the analysis of voice (vocal jitter P = 0.041, standard deviation of the average fundamental frequency P = 0.018, and the mean fundamental frequency of the vibrating vocal folds P = 0.025) differentiated the MS group from the control group. Phonatory function is impaired in MS patients, and physiological methods, such as electroglottography, are useful tools to assess it.

Voice analysis of patients with diverse types of Reinke's edema and clinical use of electroglottographic measurements

Conclusions. Reinke's edema shows a variety of clinical patterns and differences in voice analysis depending on its type. Electroglottographic measurements help to objectively assess the severity of edema and voice quality before and after surgery. Objectives. Reinke's edema manifests various clinical findings and different voice characteristics depending on the degree of swelling and the severity of voice impairment. The aim of this study was to compare the aerodynamic, acoustic and electroglottographic parameters for the different types of Reinke's edema according to its morphological, perceptual and histopathological classifications, and to assess voice quality in patients with Reinke's edema before and after laryngomicrosurgery. We also aimed to determine which parameter was most associated with the improvement in postoperative voice quality and to investigate the clinical usefulness of electroglottographic analysis in Reinke's edema. Material and methods. The clinical and voice records of 61 patients with Reinke's edema were reviewed. All the patients were classified according to stroboscopic findings (Yonekawa's classification), perceptual grade and histopathological findings. Voice analysis of the perceptual, acoustic, aerodynamic and electroglottographic measurements was carried out using various classifications, and the voices of 23 patients who underwent laryngomicrosurgery were evaluated 2 months after surgery. Furthermore, the voices of 30 normal speakers (controls) were recorded and analyzed. Results. The fundamental frequency (FxM) of Yonekawa Type III was significantly lower than those of the other types of Reinke's edema, and the SD of the FxM, the percentage irregularity of the FxM (CFx) and the percentage irregularity of the amplitude were larger than those of the other types of Reinke's edema. The closed quotient was significantly higher in Yonekawa Type III. In addition, the mean flow rate (MFR), maximum phonation time and harmonics:noise ratio (HNR) differed significantly among the different types of Reinke's edema. The postoperative results showed an increase in the FxM and an improvement in the MFR, subglottic pressure, shimmer and HNR. Correlation analysis showed that jitter, the HNR, the mean closed quotient and the irregularity of the frequency were the parameters that had the best correlation with improvement in postoperative voice quality.

Measures of vocal function during changes in vocal effort level

The purpose of this article is to present the results of a controlled study of the day-to-day variabilities of three acoustic parameters (jitter, shimmer, and normalized noise energy), and two electroglottographic parameters (contact quotient and contact quotient perturbation) for vowels produced at three vocal efforts (low, normal, high). Data were obtained with use of a sophisticated bilinear interpolation pitch detection method. A repeated measures design required subjects to produce the vowels /ae/ and /a/ five times a day over 3 days at each vocal effort level. The jitter, shimmer, and normalized noise energy values from acoustic measures and contact quotient and contact quotient perturbation values varied significantly among the three vocal effort levels. The clinical implication of this finding is that vocal effort must be controlled in order to obtain consistent clinical measures. Furthermore, day-to-day variability must be taken into account if representative measures are to be obtained for clinical use.

Does the voice improve with vocal hygiene education? A study of some instrumental voice measures in a group of kindergarten teachers

This study investigated the efficacy of a program of vocal hygiene education designed for an occupational group at risk for dysphonia, namely, kindergarten teachers. Twelve female teachers explored concepts and knowledge of vocal abuse and vocal hygiene in a workshop session and attempted to practice vocal hygiene for 2 months. They showed significant voice improvement as assessed instrumentally in terms of three acoustic and electroglottographic parameters. There was no significant change of voice in a control group of 13 teachers. The results suggest that teachers were able to improve their voices if they significantly reduced vocal abuses in daily life and practiced specific strategies to maintain classroom order and reduce the use of voice in teaching.

Comparison of Aerodynamic and Electroglottographic Parameters in Evaluating Clinically Relevant Voicing Patterns

The purpose of the present study was to identify one or more aerodynamic or electroglottographic measures that distinguish among voicing patterns that are clinically relevant for nodule pathogenesis and regression: a presumably pathogenic pattern (pressed voice), a neutral pattern (normal voice), and two presumably therapeutic patterns (resonant voice and breathy voice). Trained subjects with normal voices produced several tokens of each voice type on sustained vowels /a/, /i/, and /u/. For each token, maximum flow declination rate, alternating current flow, and minimum flow were obtained from inverse-filtered airflow signals, and closed quotient and closing time were obtained from electroglottographic signals. The results indicate that for /a/ and /i/ (but not for /u/), the closed quotient provides a sensitive tool for distinguishing the voice types in physiologically interpretable directions. Further, post-hoc analyses confirmed a direct relationship between the closed quotient and videoscopic ratings of laryngeal adduction, which previous work links to nodule pathogenesis and regression.