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Vocal effects - also called extreme or extended vocal techniques - with the intention to sound hoarse or rough are widely used as part of many genres and styles of singing, yet scarcely documented in research. Physiological studies detail the involvement of supraglottic structures for the production of vocal effects, yet the acoustic impact of such involvement has not been documented systematically across phonation types., Purpose: To report acoustic measurements and electroglottography-specific measurements for the five rough-sounding vocal effects Distortion, Growl, Grunt, Rattle, and Creaking across phonation types to demonstrate differences between notes with and without vocal effects added., Methods: Thirty-two professional singers and singing teachers produced sustained vowels in each of the four vocal modes with alternations of adding and removing the vocal effects. The singers were recorded with a microphone at a constant distance as well as with EGG., Results: The vocal effects Distortion, Growl, Grunt, Rattle, and Creaking impact the acoustic spectra in separate and systematic ways across genders and phonation types. Each vocal effect impacted the spectrum in specific and particular frequency regions between 0 and 3.5 KHz as well as in higher partials after 12 kHz with statistical significance. EGG-waveforms were un-impacted by most of the vocal effects produced using supraglottic sound sources, whereas Grunt and Creaking conditions did impact EGG-waveform signals, though not consistently between participants. EGG measures confirmed sustained and unchanged Qx and Fx for most conditions, with statically significant changes in noise measurements Harmonic-to-Noise Ratio, Normalised Noise Energy, Relative Average Perturbation, and Cepstral Peak Prominence, despite Sound Pressure Level differing significantly only for a few specific conditions. Singers scored an average of 5,95 on Voice Handicap Index questionnaires and were all reportedly healthy., Conclusions: Vocal effects added to phonation produce specific increases and specific decreases in particular frequency regions in a systematic way and can be produced in a healthy and sustainable manner, as measured by Voice Handicap Index. Vocal effects can be added to different phonation types with differing acoustic output and singers were able to sustain and control involvement of the supraglottic sound source(s) independently of phonation type., Competing Interests: Declaration of interests A previous version of this work was presented at the 2021 Voice Foundation Symposium. One author (MA) is employed in a PostDoc granted by the Danish Innovation Foundation (ref. no. 8054-00039B) which is in part given to Nottingham University Hospital of which one author (JM) is employed as an ENT laryngologist and in part to Complete Vocal Institute of which one author (CS) is employed., (Copyright © 2021 The Voice Foundation. All rights reserved.)

Electroglottography (EGG) is a technology developed for measuring the vocal fold contact area during human voice production. Although considered subjective and unreliable as a sole diagnostic method, with the correct application of relevant computational methods, it can constitute a most promising non-invasive voice disorder diagnostic tools in a form of a digital vocal tract pathology classifier. The aim of the following study is to gather and evaluate currently existing digital voice quality assessment systems and vocal tract abnormality classification systems that rely on the use of electroglottographic bio-impedance signals. To fully comprehend the findings of this review, first the subject of EGG is introduced. For that, we summarise most relevant existing research on EGG with a particular focus on its application in diagnostics. Then, we move on to the focal point of this work, which is describing and comparing the existing EGG-based digital voice pathology classification systems. With the application of PRISMA model, 13 articles were chosen and analysed in detail. Direct comparison between chosen studies brought us to pivotal conclusions, which have been described in Section 5 of this report. Meanwhile, certain limitations arising from the literature were identified, such as questionable understanding of the nature of EGG bio-impedance signals. The appropriate recommendations for future work were made, including the application of different methods for EGG feature extraction, as well as the need for continuous EGG datasets development containing signals gathered in various conditions and with different equipments., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Electroglottography (EGG) is a low-cost, noninvasive technology for measuring changes of relative vocal fold contact area during laryngeal voice production. EGG was introduced about 60 years ago and has gone through a "golden era" of increased scientific attention in the late 1980s and early 90s. During that period, four eminent review papers were written. Here, an update to these reviews is given, recapitulating some earlier landmark contributions and documenting noteworthy developments during the past 25 years. After presenting an algorithmic bibliographic analysis, some methodological aspects pertaining to measurement technology, qualitative and quantitative analysis, and respective interpretation are discussed. In particular, the interpretation of landmarks in the (first derivative of the) EGG waveform is critically examined. It is argued that because of inferior-superior and anterior-posterior phase differences of vocal fold vibration, vocal fold (de)contacting does not occur instantaneously, but over an interval of time. For this reason, instants of vocal fold closing and opening cannot be resolved exactly from the EGG signal. Consequently, any quantitative analysis parameter relying on the determination of (de)contacting events (such as the EGG contact quotient) should be interpreted with care. Finally, recent developments are reviewed for the various fields of application of EGG, including basic voice science and voice production physiology, speech signal processing and classification, clinical practice including swallowing, phonetics, hearing sciences, psychology, singing, trumpet playing, and mammalian and avian bioacoustics. Overall, EGG has over the past six decades developed into a mature technology with a wide range of applications. However, due to current limitations, the full potential of the methodology has as yet not been fully exploited. Future development may occur on three levels: (a) rigorous validation of existent measurement approaches; (b) introduction and rigorous validation of novel quantitative and interpretative approaches; and (c) advancement of the measurement technology itself., (Copyright © 2019 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Source-filter interaction is a phenomenon in which acoustic airway pressures influence the glottal airflow at the source (level 1) and the vibration pattern of the vocal folds (level 2). This interaction is most significant when dominant source harmonics are near airway resonances. The influence of acoustic airway pressures on vocal fold vibration (level 2) was studied systematically by changing the supraglottal vocal tract length in human subjects with tube extensions. The subjects were asked to perform fundamental frequency (f o ) glides while phonating through tubes of various lengths. An algorithm was developed using the quasi-open quotient extracted from the electroglottograph. Regions of sudden vocal fold vibration pattern change due to source-filter interaction were inferred from contact area changes. The algorithm correctly identified 89% of male and 84.8% of female quantal changes in contact pattern associated with interactions between source harmonics and formants during ascending glides. During the descending glides, the algorithm correctly identified 84% of male and 81.1% of female quantal changes in contact pattern. These results are in comparison with those obtained from the f o -based algorithm (Maxfield et al)., (Copyright © 2019 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Laryngopharyngeal reflux (LPR) refers to the flow of gastric acid content into the laryngopharynx. It has been reported that 10% of the patients consulting an otolaryngologist present with this condition. Signs of LPR can be identified during flexible or rigid laryngoscopy. The Voice Handicap Index (VHI) is a reliable tool for detecting the impact of voice disorders, and acoustic assessment of voice including acoustic analysis of voice (AAV) and electroglottography (EGG) provide objective data of voice production and voice disorders., Objective: This study aimed to describe changes in AAV, EGG, and VHI in patients who present with LPR compared with a matched control group of healthy subjects., Materials and Methods: Seventeen patients with LPR were studied. A group of healthy subjects matched by age and gender without any history of voice disorder, LPR, or gastroesophageal reflux disease was assembled. Both groups of patients were studied by VHI, flexible laryngoscopy, AAV, and EGG., Results: All patients with LPR demonstrated abnormal VHI values. Shimmer, jitter, open quotient, and irregularity were significantly increased in the patients with LPR. Nonsignificant correlations were found between VHI scores and abnormal acoustic parameters in patients with LPR., Conclusions: Although abnormal acoustic parameters of patients with LPR were not predictive of the overall VHI score, the abnormal acoustic parameters of patients with LPR suggest a decrease in adequate laryngeal control during phonation., (Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Acoustic analysis of voice (AAV) and electroglottography (EGG) have been used for assessing vocal quality in patients with voice disorders. The effectiveness of these procedures for detecting mild disturbances in vocal quality in elite vocal performers has been controversial., Objective: To compare acoustic parameters obtained by AAV and EGG before and after vocal training to determine the effectiveness of these procedures for detecting vocal improvements in elite vocal performers., Materials and Methods: Thirty-three elite vocal performers were studied. The study group included 14 males and 19 females, ages 18-40 years, without a history of voice disorders. Acoustic parameters were obtained through AAV and EGG before and after vocal training using the Linklater method., Results: Nonsignificant differences (P > 0.05) were found between values of fundamental frequency (F 0 ), shimmer, and jitter obtained by both procedures before vocal training. Mean F 0 was similar after vocal training. Jitter percentage as measured by AAV showed nonsignificant differences (P > 0.05) before and after vocal training. Shimmer percentage as measured by AAV demonstrated a significant reduction (P < 0.05) after vocal training. As measured by EGG after vocal training, shimmer and jitter were significantly reduced (P < 0.05); open quotient was significantly increased (P < 0.05); and irregularity was significantly reduced (P < 0.05)., Conclusions: AAV and EGG were effective for detecting improvements in vocal function after vocal training in male and female elite vocal performers undergoing vocal training. EGG demonstrated better efficacy for detecting improvements and provided additional parameters as compared to AAV., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The study aimed to investigate whether humming can immediately improve the regularity of vocal fold vibration on electroglottography (EGG) and laryngeal high-speed digital imaging (HSDI) in patients with organic dysphonia (OD)., Methods: In a series of 49 dysphonic patients who were diagnosed to have benign mass lesions in the vocal folds and an equal number of non-dysphonic speakers, perturbation parameters were calculated on the acoustic (Ac) and EGG signals during natural and humming phonation. In addition, 11 OD patients and as many non-dysphonic speakers underwent simultaneous EGG and HSDI video recording under laryngofiberscopy while performing the two tasks. The perturbation parameters of the EGG signals as well as the glottal area waveforms (GAW), which were extracted from the HSDI movies, were calculated, and the correlations between both perturbation parameters were analyzed., Results: Humming achieved significant improvements in the EGG perturbation parameters in both groups. More than half of the OD patients showed decreased EGG perturbation parameters to the level of those during natural phonation in the control group. With respect to the GAW analysis, moderate correlations were observed between both period and amplitude perturbation parameters (period: r = 0.63, amplitude: r = 0.41). Humming decreased both GAW perturbation parameters significantly in the OD and control subjects combined., Conclusions: These results demonstrate that in OD patients, humming has a potential to improve voice quality by stabilizing the vocal fold oscillation, and suggest that humming can remove the functional component in the vocal disturbance instead of the mechanical effect of the mass lesions., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: To make a comparative analysis on the closed quotient (CQ) of the sustained vowel /e/ while fasting and nonfasting., Study Design: Cross-sectional study., Methods: A total of 20 male subjects were enrolled. The mean age was 30.45 ± 8.79 years with a range of 20-48 years. The mean weight while nonfasting was 79.66 ± 12.91 kg and while fasting was 78.51 ± 12.70 kg. Demographic data included age, history of smoking, and weight. All subjects were evaluated while fasting and nonfasting. All subjects underwent laryngeal electroglottography while phonating the vowel /e/ at a comfortable pitch and loudness. The mean CQ, range, and standard deviations were computed while fasting and nonfasting. The degree of phonatory effort and vocal fatigue was also reported on a scale of 0-3., Results: The difference in weight while fasting and nonfasting was statistically significant (P=0.001). There was no significant difference between the mean CQ while fasting versus nonfasting (44.49 ± 1.15 and 44.30 ± 1.41, P=0.94). The difference in the mean grade of phonatory effort was borderline significant (P=0.059) with 40% of the subjects having an increase in effort. With respect to vocal fatigue, there was an increase in the average while fasting by 0.25, which was statistically nonsignificant (P=0.109)., Conclusions: The mean CQ during sustained /e/ is not affected by fasting. The presence of increased vocal effort and vocal fatigue could be secondary either to dehydration or respiratory muscle fatigue accompanying the weight loss., (Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: Slantwise-placed electroglottography (EGG) was proposed for synchronous use with an ultrasound machine in a previous work. The objective was to confirm the feasibility of this slant EGG, differentiate it from conventional EGG, and give suggestions for its applications., Study Design and Methods: A synchronized system composed of an EGG device, a high-speed video, a sound level meter, and a headset was established. The same phonation conditions were acquired by training subjects to reach the target phonation frequency and intensity. Electrode position was designed, and vocal fold vibration parameters were measured from EGG waveforms recorded in each electrode position., Results: Comparison showed that the characteristic points identified in slant EGG waveforms were consistent with the vibration phase shown by high-speed video images. Phonation frequency measured from slant EGG was highly accurate. EGG amplitude nonlinearly decreased with the increase of electrode distance. Compared with conventional EGG parameters, velocity ratio and glottal closed quotient measured from slant EGG were accurate when electrodes were placed symmetrically and the electrode distance was within a proper length., Conclusions: Slant EGG was proved feasible and can be considered as a useful tool to obtain comprehensive information in investigating the in vivo vocal fold dynamics when synchronized with other detecting equipment., (Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: To compare the mean and standard deviation (SD) of the contact quotient (CQ) of the sustained vowels ([a] and [e]) in multiple sclerosis (MS) patients versus controls., Study Design: Cross-sectional study., Materials and Methods: Thirty-nine subjects (24 patients and 15 controls) participated in this study. Laryngeal electroglottography was performed on all subjects while phonating the vowels [a] and [e] at a comfortable pitch and loudness. The fundamental frequency, mean CQ, SDs, and jitter were computed for both vocal tasks., Results: The mean age of the MS group was 36.25+10.61 years. All laryngeal examinations were normal and five patients with MS had dysphonia described as voice breaks and fatigue in connected speech. For both vowels [a] and [e], the mean closed quotients were comparable in groups, MS and control (43.90 vs 53 for [a] and 44.75 vs 43.63 for [e]) with no significant difference. When comparing five MS patients with dysphonia versus controls, for the vowel [a], the mean closed quotient was significantly lower in MS patients with dysphonia (P values of 0.043)., Conclusion: The mean closed quotient for sustained vowels [a] and [e] are comparable in MS patients and healthy controls except in patients with dysphonia., (Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.)

Objective: This investigation used synchronous high-speed videoendoscopy and electroglottography (EGG) to systematically study contact and separation behavior along the length of the vocal folds., Design: Repeated measures., Methods: Facilitated by EGG and digital kymograms derived at 20%, 35%, 50%, 65%, and 80% of the posteroanterior length of the vocal folds, the pattern of vocal-fold contact and separation was determined for seven female and seven male vocally healthy subjects while producing "breathy," "comfortable," and "pressed" phonations., Results: The female subjects consistently used an anterior-to-posterior contact pattern and posterior-to-anterior separation pattern when producing a breathy or comfortable voice, with several using a simultaneous pattern of contact and/or separation for pressed phonation. The male subjects showed more variable "zipperlike" separation patterns, but consistently used a simultaneous contact pattern for pressed voice that was also commonly used when producing comfortable phonation., Conclusions: Findings indicate longitudinal phase differences in vocal-fold vibration are both common and expected in vocally healthy speakers. The implications for vocal assessment, as well as for the use and interpretation of the EGG signal, are discussed., (Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.)

Vocal fold oscillation patterns in vocal register transitions are still unclarified. The vocal fold oscillations and the open quotient were analyzed with high-speed digital imaging (HSDI) and electroglottography (EGG) in 18 male untrained subjects singing a glissando from modal to the falsetto register. Results reveal that the open quotient changed with register in both HSDI and EGG. The in-class correlations for different HSDI and EGG determinations of the open quotient were high. However, we found only weak interclass correlations between both methods. In 10 subjects, irregularities of vocal fold vibration occurred during the register transition. Our results confirm previous observations that falsetto register is associated with a higher open quotient compared with modal register. These data suggest furthermore that irregularities typically observed in audio and electroglottographic signals during register transitions are caused by irregularities in vocal fold vibration., (Copyright © 2010 The Voice Foundation. Published by Mosby, Inc. All rights reserved.)

The incidence of dysphonia in healthy elderly people is high. In individuals with iatrogenic vocal-fold paresis following thyroid surgery, serious aggravation of vocal skills contributes to impaired quality of life and requires proper management. Electroglottography is a common method for providing noninvasive measurements of glottal activity, yielding reliable indicators of glottal closing instants. The purpose of the study was to determine how electroglottography measures change with voice recovery in elderly speakers with vocal-fold palsy, compared with healthy elderly individuals, and which coefficient best represents dysphonia. An electroglottograph with Speech Studio 1.04 software was used to record and analyze the data. Electroglottography data were collected from 12 patients aged 65-78 years (mean=71.3, S.D.=3.8, median=71) and 10 healthy speakers aged 65-77 years (mean=70.9, S.D.=3.9, median=72). The findings show that the distribution of values of % irregularity differs between the groups of patients and controls. % Irregularity and closing quotient significantly correlate with the perceptual degree of dysphonia. Electroglottography can objectify dysphonia in elderly patients with vocal-fold palsy and is a suitable noninvasive tool for tracking the elderly patients' long-term progress. % Irregularity best represents the vocal-fold dysfunction in elderly patients with a vocal-fold palsy.

We evaluate a group of patients who have mobile vocal folds, but have flexible laryngeal examinations suspicious for mild vocal fold paresis. The purpose of this retrospective study is to evaluate if electroglottography (EGG) can predict the probability of having an abnormal laryngeal electromyography (LEMG). Charts of patients evaluated and suspected of having mild vocal fold paresis between August 1, 2004 and March 30, 2006 were reviewed. We compared average EGG contact quotients (CQs), average absolute difference of recorded CQ from normal (|CQ-50%|), and EGG waveforms between patients with normal and abnormal LEMG. Waveforms were evaluated in blinded fashion. Statistical analysis was performed using chi square and t test analyses. One hundred and sixteen patients received both flexible laryngoscopy and LEMG as part of their evaluation. Forty-eight patients (41%) had confirmed paresis by LEMG and 68 patients (59%) had normal LEMGs. Only 9.1% of patients with a normal EGG waveform had an abnormal LEMG. In contrast, 40.4% of patients with an abnormal EGG waveform had abnormal LEMGs. The negative predictive value of a normal EGG waveform for an abnormal LEMG was 90.9%. No significant differences were identified between patients with normal versus abnormal LEMG in terms of average CQ (47.8% vs 46.4%) or |CQ-50%| (6.2 vs 5.6). Patients with a normal EGG waveform are unlikely to have an abnormal LEMG.

This study was designed to develop a database for the electroglottographic measurement of fundamental frequency (Fo) in normal subjects in running speech, for reference in the diagnosis and follow-up of dysphonic patients. A prospective pilot study included 20 healthy male volunteers without laryngeal disorder. Electroglottographic recordings of speaking Fo during connected speech (French) were obtained from two texts with different prosodic content. Fo histograms were sensitive to the variation of speaking Fo between both texts. Graphic representation of the range and distribution of the Fo of the speaker were designed as normalized Fo histograms with plot lines at 5th and 95th percentiles. Less than 5% variability of Fo histograms was recorded when recording more than 15 subjects. This pilot study designed a graphic display of standardized electroglottographic Fo measurements during the physiological condition of connected speech. As the degree of Fo variability depends on the phonetic contents of the text and on the language spoken, a separate histogram for normal subjects needs to be developed in each country or at least for each voice laboratory, with a standard, previously chosen text.

Drug abuse can cause severe damage to the human speech organs. The vocal folds are one of the important speech organs that produce voice through vibration when airflow passes through. Previous studies have reported the negative effects of drugs on speech organs, including the vocal folds, but there is still limited research on relevant field. Therefore, the current study recruited 25 heroin users and 30 healthy controls with no history of drug use. Electroglottography and speech signals of 26 target sentences were collected from all participants. The results of the current study showed that the heroin group exhibited higher DFx1 and H1-A3, and lower DAx1 and jitter, and lower F1 frequency for /a/ and F2 frequency for /i/, but higher F2 frequency for /u/ compared to the no drug group. These findings suggested the presence of vocal hoarseness, frequency and amplitude distributions that differed from the norm, and a limited range of tongue movement in the heroin group. This study not only enhances the understanding of the effects of heroin on speech production but also has implications for detoxification treatment and speech rehabilitation for drug users., Competing Interests: Declaration of Competing Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2025 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study aimed to identify voice instabilities across registration shifts produced by untrained female singers and describe them relative to changes in fundamental frequency, airflow, intensity, inferred adduction, and acoustic spectra., Study Design: Multisignal descriptive study., Methods: Five untrained female singers sang up to 30 repetitions of octave scales. They first produced these octave scales "naturally," followed by productions that were either deliberately smooth or deliberately unsteady. With all types of scale productions, participants sang with both /α/ and /i/ vowels, at two different dynamic levels, and across both the upper and lower predetermined register transitions. Recorded scales were categorized into three groups (Smooth, Middle, Unsteady) based on researcher-based perceptual smoothness of the auditory signals. These groups allowed for determination of salient features of unsteadiness based on observations and analyses of the acoustic, airflow, intensity, and electroglottography (EGG) waveforms., Results: A total of 13 different types of instabilities were observed. The number of instabilities within a single scale ranged from zero to fourteen. Most Smooth scales had zero to three instabilities, most Middle scales had four to six, and most Unsteady scales had six or more instabilities within the scale. More obvious instabilities, such as aphonic segments, were present only in Unsteady scales, while more subtle instabilities, such as those related to EGG signal changes, were common in all scale categories, including Smooth scales., Conclusions: This study revealed that untrained singers can sing smoothly throughout octave scales, and the primary unsteadiness variable was an aphonic segment and corresponding abrupt and large intensity reduction. Particular instabilities may be related to subtle aspects of register change and vocal control. Some objective measures appear to be more visually and numerically salient than auditorily perceived events relative to unsteadiness in the production of scales., Competing Interests: Declaration of Competing Interest The authors have no conflicts. They also have no financial or non-financial relationships to disclose. The material has not been published elsewhere. Both co-authors made major contributions throughout the project. No artificial intelligence was used to create any phrases or sentences., (Copyright © 2025 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: 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., Methods: 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., Results: 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 (f o ) values occurred in the pairwise comparisons of the procedures in the measurements after the exercises., Conclusion: 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., (Copyright © 2022 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Introduction: The upper esophageal sphincter (UES) has been reported to show activity during phonation. As it is still unknown whether the phonation-induced UES contraction represents a reflex or a simultaneous activation phenomenon, i.e. co-innervation, this study aims to investigate and characterize the phonation-induced contraction of the UES in healthy individuals by analyzing the influence of various phonation tasks on pressure parameters of the UES., Methods: Twenty-five healthy volunteers produced the German neutral vowel [ə] in five different phonation tasks (modal voice, whispering, voiceless speech, creaky voice, and whispery voice). Simultaneously, they underwent high resolution manometry and electroglottography for measurement of pressure parameters in the region of the UES and latencies between larynx and UES activation., Results: During all types of phonation, the maximum pressures of the UES increased significantly (maximum pressure increases of 72%-132%). With regard to mean pressures this was valid for modal voice and whispering (mean pressure increases of 20%-25%). Differences concerning total pressure changes reached statistical significance when comparing whispering and voiceless speech as well as whispery voice. However, differences concerning the total pressure change between modal voices on the one hand and voiceless speech and whispery voice on the other hand turned out to be small. The averaged time delay between larynx and UES activation ranged from approximately -15 ms (whispery voice) to +15 ms (whispering)., Conclusion: A phonation induced pressure increase of the UES was confirmed in this study and did exist for different types of phonation. The extent of total pressure changes in the UES increases in relation with laryngeal muscle activity necessary for the phonation type. Next to varying effects of different types of phonation on UES activation, very short latencies indicate that a phonation induced contraction of the UES exists most likely due to co-innervation of UES and laryngeal muscles by the vagus nerve., Competing Interests: Declaration of interest None, (Copyright © 2022 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Voice registers are assumed to be related to different laryngeal adjustments, but objective evidence has been insufficient. While chest register is usually associated with the lower pitch range, and head register with the higher pitch range, here we investigated a professional singer who claimed an ability to produce both these registers at every pitch, throughout her entire singing range. The singer performed separated phonations alternating between the two registers (further called chest-like and head-like) at all pitches from C3 (131 Hz) to C6 (1047 Hz). We monitored the vocal fold vibrations using high-speed video endoscopy and electroglottography. The microphone sound was recorded and used for blind listening tests performed by the three authors (insiders) and by six "naive" participants (outsiders). The outsiders correctly identified the registers in 64% of the cases, and the insiders in 89% of the cases. Objective analysis revealed larger closed quotient and vertical phase differences for the chest-like register within the lower range below G4 (<392 Hz), and also a larger closed quotient at the membranous glottis within the higher range above Bb4 (>466 Hz), but not between Ab4-A4 (415-440 Hz). The normalized amplitude quotient was consistently lower in the chest-like register throughout the entire range. The results indicate that that the singer employed subtle laryngeal control mechanisms for the chest-like and head-like phonations on top of the traditionally recognized low-pitched chest and high-pitched head register phenomena. Across all pitches, the chest-like register was produced with more rapid glottal closure that was usually, but not necessarily, accompanied also by stronger adduction of membranous glottis. These register changes were not always easily perceivable by listeners, however., (Copyright © 2022 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: This study aims to investigate the immediate effect of straw phonation on the phonation of Persian-speaking children with repaired cleft palate., Study Design: Quasi-experimental preintervention and postintervention., Methods: Seventeen children with repaired cleft palate and velopharyngeal dysfunction were investigated. A control group was established comprising children without a cleft palate (control group), carefully matched in terms of age and gender. All participants underwent straw phonation and assessment. The assessments were made two times: at baseline and immediately after straw phonation. Each participant performs straw phonation (a short straw measuring 3 mm in inner diameter and 20 cm in length) once for 3 minutes. The acoustic analysis including parameters, such as jitter, shimmer, harmonics-to-noise ratio (HNR), cepstral peak prominence (CPP) parameters, as well as the electroglottography (closed quotient [CQ]) analysis were performed at pretreatment and immediately after treatment., Results: Compared with the pretreatment values, after-treatment observation demonstrated a significant reduction in Jitter % and Shimmer %, and a significant enhancement in HNR and CPP among children with repaired cleft palate. There is no significant difference in intragroup data in the CPP and CQ in pretreatment., Conclusions: The proposed straw phonation technique results in an immediate positive change in the quality of voice in both groups. Moreover, assessments in the clinical group showed a significant decrease in shimmer and jitter perturbation, alongside elevated levels of HNR and CPP subsequent to straw phonation, irrespective of the phonatory task., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of the study is to investigate the use of incidences and characteristics of Prevocalic Electroglottographic Signal (PVES) derived from electroglottography (EGG) in characterizing glottal stops (GS) in cleft palate speech., Methods: Mandarin nonaspirated monosyllabic first-tone words were used for the speech sampling procedure. A total of 1680 utterances (from 83 patients with repaired cleft palates) were divided into three categories based on the results of auditory-perceptual evaluation of recorded speech sounds by three independent reviewers: [Category A (absence of GS agreed by all three reviewers) (n = 1192 tokens), Category B (two out of three reviewers agreed on the presence of a GS) (n = 181 tokens) and Category C (all three reviewers agreed on the presence of a GS) (n = 307 tokens)]. The EGG signals of the 1680 utterances were analyzed using a MATLAB program to automatically mark the instances of PVES (amplitude and time-interval) in the GS utterances., Results: The result showed that the incidence of EGG PVES presented good positive correlation with auditory-perceptual evaluation (r = 0.703, P＜0.000). Statistical analysis revealed a significant difference in mean PVES amplitude among different groups (P＜0.05). There was a significant distinction in the time interval between groups A and B, as well as in groups A and C (P＜0.05)., Conclusions: The study suggests PVES can be an objective means of identifying GS in cleft palate speech. It also indicates that proportion of amplitude and time interval of PVES tend to be positively correlate with subjective assessment., Competing Interests: Declaration of Competing Interest The authors declare that there is no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Coughing is related to voice problems, since it involves firm glottal closure, fast glottal opening, and high subglottic pressure and flow rate. In this study, the glottal area variation and movements of laryngeal structures during coughing and phonation are compared., Methods: High-speed laryngoscopy recordings were made of a normophonic male participant with a healthy larynx producing a neutral vowel and coughing. Oral air pressure was registered in a mouthpiece, through which an endoscope was inserted into the pharynx. Electroglottography, acoustic, and pressure signals were recorded simultaneously. The glottal width variation at the membranous and cartilaginous parts of the glottis was derived from the high-speed images, and the strong vibration of the false vocal folds was also registered., Results: In coughing, compared to ordinary vowel phonation in nearly the same sound pressure level (93-94 dB 6cm ), the glottal width was 25% larger at the middle of the vocal folds, the maximum glottal opening velocity was 39% higher, and the maximum glottal width declination rate during glottal closing was up to three times higher. The maximum acceleration was 40% higher, and the maximum deceleration was 47% higher. Fundamental frequency f 0 was the highest (ca. 400 Hz) at the beginning of the first phase of a typical coughing process. During the last part of the coughing process, f 0 decreased from ca. 250 Hz to ca. 85 Hz at the phonation offset., Conclusions: The remarkable increase in maximum glottal width declination rate implies much higher vocal fold loading in coughing compared to phonation., (Copyright © 2023 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

The acts of speaking and singing are different phenomena displaying distinct characteristics. The classification and distinction of these voice acts is vastly approached utilizing voice audio recordings and microphones. The use of audio recordings, however, can become challenging and computationally expensive due to the complexity of the voice signal. The research presented in this paper seeks to address this issue by implementing a deep learning classifier of speaking and singing voices based on bioimpedance measurement in replacement of audio recordings. In addition, the proposed research aims to develop a real-time voice act classification for the integration with voice-to-MIDI conversion. For such purposes, a system was designed, implemented, and tested using electroglottographic signals, Mel Frequency Cepstral Coefficients, and a deep neural network. The lack of datasets for the training of the model was tackled by creating a dedicated dataset 7200 bioimpedance measurement of both singing and speaking. The use of bioimpedance measurements allows to deliver high classification accuracy whilst keeping low computational needs for both preprocessing and classification. These characteristics, in turn, allows a fast deployment of the system for near-real-time applications. After the training, the system was broadly tested achieving a testing accuracy of 92% to 94%., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Typical singing registers are the chest and falsetto; however, trained singers have an additional register, namely, the mixed register. The mixed register, which is also called "mixed voice" or "mix," is an important technique for singers, as it can help bridge from the chest voice to falsetto without noticeable voice breaks., Objective: The present study aims to reveal the nature of the voice-production mechanism of the different registers (chest, mix, and falsetto) using high-speed digital imaging (HSDI), electroglottography (EGG), and acoustic and aerodynamic measurements., Study Design: Cross-sectional study., Methods: Aerodynamic measurements were acquired for twelve healthy singers (six men and women) during the phonation of a variety of pitches using three registers. HSDI and EGG devices were simultaneously used on three healthy singers (two men and one woman) from which an open quotient (OQ) and speed quotient (SQ) were detected. Audio signals were recorded for five sustained vowels, and a spectral analysis was conducted to determine the amplitude of each harmonic component. Furthermore, the absolute (not relative) value of the glottal volume flow was estimated by integrating data obtained from the HSDI and aerodynamic studies., Results: For all singers, the subglottal pressure (P Sub ) was the highest for the chest in the three registers, and the mean flow rate (MFR) was the highest for the falsetto. Conversely, the P Sub of the mix was as low as the falsetto, and the MFR of the mix was as low as the chest. The HSDI analysis showed that the OQ differed significantly among the registers, even when the fundamental frequency was the same; the OQ of the mix was higher than that of the chest but lower than that of the falsetto. The acoustic analysis showed that, for the mix, the harmonic structure was intermediate between the chest and falsetto. The results of the glottal volume-flow analysis revealed that the maximum volume velocity was the least for the mix register at every fundamental frequency. The first and second harmonic (H1-H2) difference of the voice source spectrum was the greatest for the falsetto, then the mix, and finally, the chest., Conclusions: We found differences in the registers in terms of the aeromechanical mechanisms and vibration patterns of the vocal folds. The mixed register proved to have a distinct voice-production mechanism, which can be differentiated from those of the chest or falsetto registers., (Copyright © 2021 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: This study analyzes the effects of the vocal exercises called semi-occluded nasal tract exercises (SONTEs), which were carried out with a new appliance that extends the nasal cavity as a part of the vocal tract. The acoustic, aerodynamic and electroglottographic (EGG) measurements were compared with those of the traditional semi-occluded vocal tract exercises (SOVTEs) of phonation in water., Methods: In this study, 34 women were randomly asked to perform phonation in water for 5 min through the nasal and oral routes with the sounds /m/ and /ɔ/, respectively, using a tube with a submersion depth of 5 cm. The acoustic, aerodynamic and EGG measurements before and after the exercises were analyzed using the appropriate statistical methods., Results: No significant difference was found in the time and frequency domain parameters before and after the exercises, except for the amplitude perturbation quotient (APQ) values, which decreased after both exercises. In addition, there was no significant difference in any aerodynamic parameters before and after the exercises, but the mean SPL values significantly increased after both exercises. The oral and nasal peak inspiratory flow rates increased after both exercises, but the increase peaked after the SONTEs implementation. As expected, the EGG-jitter and EGG-periodicity values had a reciprocal interaction with each other, while differences were observed between the values of the vocal fold movements measured in both exercises., Conclusions: SONTEs may be as effective as the conventional SOVTEs because it made tube phonation into water possible through artificial extension of the nasal cavity and increased the resonant effect by using the positive effects based on the principles of SOVTEs., Competing Interests: CONFLICT OF INTEREST Authors declare that there is no conflict of interest in this study., (Copyright © 2022 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: To confirm the data reported in our previous studies on the analysis of the variability of the electroglottographic signal in the pathological voice; to evaluate possible differences in variability between organic and functional pathologies; to identify any distinctive/typical EGG patterns for these pathologies., Methods: One hundred twenty-five subjects were enrolled (36 euphonic and 89 pathological: 24 functional dysphonia, 21 bilateral vocal nodules, 23 unilateral polyps and 21 unilateral cysts). All subjects were studied with videolaryngostroboscopy, spectrographic analysis of voice and electroglottography (EGG). The EGG signal variability was then investigated using amplitude-speed combined analysis, by means of a proprietary software algorithm. Amplitude and Speed variation were expressed as a new parameter, the Variability Index (VI), calculated both for the whole EGG signal recorded (VI-tot) and in each phase of the glottic cycle (VI-Q, absolute value; VI-Q%, percentage value)., Results: In the comparison of VI values between pathological and normal groups, VI-tot and VI-Q2% (which corresponds to the final phase of vocal fold contact) were significantly greater in pathological subjects (P= 0.002). The comparison of VI values among subgroups of the various pathologies showed a difference for VI-tot (P< 0.0001) and VI-Q2% (P= 0.001); this difference was more marked in the cysts than in the functional dysphonia. The cut-off values of VI-tot and VI-Q2% were 0.191 and 18.17%, respectively (sensitivity and specificity 65.2% and 66.7% for VI-tot and 84.3% and 77.8% for VI-Q2%)., Conclusions: The variability of the EGG signal investigated through the combined analysis of the amplitude and the speed of vibration using a proprietary algorithm software has proved useful not only to distinguish the normal voice from the pathological voice, but also to characterize which phases are more altered in the various voice pathologies studied, both functional and organic. Furthermore, the analysis of the VI parameter allowed to propose cut-off values characterized by a good sensitivity and specificity to discriminate dysphonia from the euphonic voice. Larger groups of patients will be needed to confirm these results., Competing Interests: Conflicts of interest None., (Copyright © 2020 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Subharmonics are an important class of voice signals, relevant for speech, pathological voice, singing, and animal bioacoustics. They arise from special cases of amplitude (AM) or frequency modulation (FM) of the time-domain signal. Surprisingly, to date there is only one open source subharmonics detector available to the scientific community: Sun's subharmonic-to-harmonic ratio (SHR). Here, this algorithm was subjected to a formal evaluation with two data sets of synthesized and empirical speech samples. Both data sets consisted of electroglottographic (EGG) signals, ie, a physiological correlate of vocal fold oscillation that bypasses vocal tract acoustics. Data Set I contained 2560 synthesized EGG signals with varying degrees of AM and FM, fundamental frequency (fo), periodicity, and signal-to-noise ratio (SNR). Data Set II was made up of 25 EGG samples extracted from the CMU Arctic speech data base. For a "ground truth" of subharmonicity, these samples were manually annotated by a group of five external experts. Analysis of the synthesized data suggested that the SHR metric is relatively robust as long as the subharmonic modulation extent is below 0.35 and 0.7 for the FM and AM scenarios, respectively. In the CMU Arctic speech data samples, the SHR analysis reached a maximum sensitivity of about 87% at a specificity of over 90%, but only for adaptive algorithm parameter settings. In contrast, the algorithm's default parameter settings could only successfully classify about 9% of all subharmonic instances. The SHR is a useful metric for assessing the degree of subharmonics contained in voice signals, but only at adaptive parameter settings. In particular, the frequency ceiling should be set to five times the highest fo, and the frame length to at least five times the largest fundamental period of the analyzed signal. For subharmonic classification a threshold of SHR  ≥  0.01 is recommended., (Copyright © 2019 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: Inspiratory Vocal Fry (IVF) is the voice production during inspiration of a sound with vocal fry perceptual characteristics. The existing scientific literature shows a lack of studies on it. The aim of the study is to highlight anatomical and physiological characteristics of IVF, to assess its effects on spoken and singing voice, to confirm the potential usefulness in speech therapy and vocal pedagogy., Methods: Thirty-two healthy subjects (17 male and 15 female) underwent videolaryngostroboscopy to assess the degree of false vocal folds adduction, pharyngeal wall contraction, and degree of vocal folds stretching in different types of phonation: expiratory and inspiratory phonation, Expiratory Vocal Fry (EVF) and IVF. All these parameters were evaluated by a group of three speech therapists and one phoniatrician not belonging to the research group. In addition, for each subject an electroglottography was performed for all the types of phonation previously mentioned, highlighting Contact Quotient (CQ) and Closing/Closed Quotient (CCQ). Three subjects underwent electromyography for a preliminary study of the muscle activation in IVF., Results: False vocal folds adduction (P value = 0.000005) and pharyngeal wall contraction (P value = 0.001155) were significantly reduced in IVF compared to EVF; on the contrary, vocal folds stretching was significantly higher in IVF (P value = 0.000031). Electroglottographic CQ was significantly higher in IVF compared to EVF (P value = 0.019592) and the other types of phonation. Similar results were obtained considering CCQ, as IVF values for this parameter was significantly higher compared to EVF (P value = 0.013062) and expiratory phonation (P value = 0.001324). As regards electromyography, medial thyroarytenoid (TA) motor units were more recruited in IVF, while lateral TA motor units were more recruited in EVF. According to our results, IVF is characterized by higher elastic tension due to a reduced hypertonic contraction of TA muscle and a higher contraction of cricothyroid muscle. Electroglottographic results showed a wider vibratory cycle with an improved massaging effect on vocal folds mucosa. electromyography preliminary analysis confirmed our findings., Conclusion: IVF could be an excellent and useful exercise to reduce muscular hypertonic tension and to facilitate mucosal elasticity. It could be potentially applied in speech therapy approach to dysfunctional and organic dysphonias, post-surgical treatment, in pedagogy and practice of artistic voice., (Copyright © 2019 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: To assess and quantify singers' strategies for adding air to phonation to sound "breathy" in a healthy manner STUDY DESIGN: Case-control study with 20 professional singers., Methods: Twenty singers were recorded performing sustained vowels in the Complete Vocal Technique Neutral vocal mode with and without audible air added to the voice by means of laryngostroboscopic imaging using a videonasoendoscopic camera system, electroglottography, long-term average spectrum, as well as acoustic signals and audio perception. Singers completed Voice Handicap Index and Reflux Symptom Index questionnaires prior to examination., Results: Air added to the voice resulted in an expected glottal gap along the length of the vocal folds, with little to no further difference in the supraglottic area, as compared with the Neutral phonation. Air added resulted in lowered Qx, mean Sound Pressure Level, and Cepstral Peak Prominence, but higher Harmonics-to-Noise Ratio, Jitter, and Shimmer, with decreased energy at the fundamental frequency. Adding audible air to the phonation did not exhibit similar effects on acoustics for males and females. Also, for females, H1-H2 difference decreased with air added, while it increased for males., Conclusion: Singers produce an audible airy phonation similar yet significantly different to the breathy phonation reported for both healthy and pathological speakers., (Copyright © 2019 The Voice Foundation. All rights reserved.)

Objectives: This study aimed to assess whether or not humming can help increase vocal intensity gradually with only a slight increase in the glottal contact and supraglottic compression., Methods: Seventeen healthy nondysphonic speakers were asked to perform two phonatory tasks in order: gradually increasing vocal loudness (crescendo) during sustained phonation of a vowel or production of a hum (vowel- or humming-crescendo task: VCT or HCT, respectively), while the sound pressure levels (SPL), electroglottographic (EGG) signals and high-speed laryngeal movies were simultaneously recorded. The glottal contact parameter of the EGG signals and the glottal opening and laryngeal outlet parameters as well as the duration of prephonatory transient glottal closure on the laryngeal movies were calculated., Results: With a gradual SPL increase during both tasks, most participants showed a progressive decrease in the LO, but no discernible change in the EGG glottal contact. In comparisons between tasks, an HCT produced a significantly lower SPL, greater laryngeal outlet parameter value and shorter prephonatory transient glottal closure duration than a VCT. A significant difference between tasks was found in the proportion of failed task performance due to an abrupt SPL increase (41% and 6% in VCT and HCT, respectively; P = 0.011), and the failed VCTs showed a significantly higher EGG contact parameter value than the successful VCTs., Conclusion: These results demonstrate that during an gradual increase in vocal intensity, humming alleviates the enhancement in both the glottal contact and supraglottic compression, leading to the prevention of an abrupt increase in vocal intensity instead of adequate vocal output., (Copyright © 2019 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Purpose: The present study aimed at observing the possible differential effects of eight semioccluded vocal tract exercises (SOVTE) on vocal economy measured by the Quasi Output Cost Ratio (QOCR)., Methods: Thirty-six participants were included in this study. They were divided into two groups: an experimental group of subjects diagnosed with mild hyperfunctional dysphonia (n = 17) and a control group of vocally healthy subjects (n = 19). Participants were required to randomly select and produce a series of three SOVTE from a list of eight exercises. The electroglottographic based measure QOCR was used to calculate the vocal economy before and after each voice exercise., Results: Significant differences were found when comparing pre and poststages regardless of the vocal condition (normal voice or dysphonia) or the specific SOVTE used. Moreover, when individually comparing the effect of each SOVTE, only tube in water (10 cm) showed significant differences between pre and postconditions (QOCR values were higher after exercises)., Conclusion: In general, semioccluded vocal tract exercises tend to increase vocal economy regardless the vocal condition (normal voice or dysphonia) or the specific SOVTE used. Phonation into a tube submerged deep into water promoted the highest increase in vocal economy. An increased acoustic output, nonproportional increase in vocal folds adduction and an effortless voice production would cause this increase in vocal economy after water resistance therapy., (Copyright © 2019 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: To determine if in singing there is an effect of lung volume on the electroglottographic waveform, and if so, how it varies over the voice range., Study Design: Eight trained female singers sang the tune "Frère Jacques" in 18 conditions: three phonetic contexts, three dynamic levels, and high or low lung volume. Conditions were randomized and replicated., Methods: The audio and EGG signals were recorded in synchrony with signals tracking respiration and vertical larynx position. The first 10 Fourier descriptors of every EGG cycle were computed. These spectral data were clustered statistically, and the clusters were mapped by color into a voice range profile display, thus visualizing the EGG waveform changes under the influence of f o and SPL. The rank correlations and effect sizes of the relationships between relative lung volume and several adduction-related EGG wave shape metrics were similarly rendered on a color scale, in voice range profile-style 'voice maps.', Results: In most subjects, EGG waveforms varied considerably over the voice range. Within subjects, reproducibility was high, not only across the replications, but also across the phonetic contexts. The EGG waveforms were quite individual, as was the nature of the EGG shape variation across the range. EGG metrics were significantly correlated to changes in lung volume, in parts of the range of the song, and in most subjects. However, the effect sizes of the relative lung volume were generally much smaller than the effects of f o and SPL, and the relationships always varied, even changing polarity from one part of the range to another., Conclusions: Most subjects exhibited small, reproducible effects of the relative lung volume on the EGG waveform. Some hypothesized influences of tracheal pull were seen, mostly at the lowest SPLs. The effects were however highly variable, both across the moderately wide f o -SPL range and across subjects. Different singers may be applying different techniques and compensatory behaviors with changing lung volume. The outcomes emphasize the importance of making observations over a substantial part of the voice range, and not only of phonations sustained at a few fundamental frequencies and sound levels., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Glottal stop (GS) is a typical compensatory articulation, which has a great impact on speech intelligibility in patients with cleft palate. It is usually detected by perceptual analysis. The aim of this study is to investigate the utility of vocal attack time (VAT) values in patients with cleft palate with and without GS, when unaspirated monosyllables are articulated in Mandarin, by using electroglottography. Unaspirated monosyllables /pa/ /pi/ /pu/ /ta/ /ti/ /tu/ /ka/ /ki/ /ku/ with tone one were analyzed. A total of 575 tokens were obtained from 42 patients with cleft palate, divided into a GS category (n = 312 tokens) and a nonglottal stop (NGS) category (n = 263 tokens), as assessed perceptually by three judges. Sound pressure and electroglottography recordings were also obtained from these tokens. The time lag of the cross-correlation function was used to gain VAT values. The results showed that the mean VAT values of tokens from the GS category (-0.25 ms) was significantly shorter than that of tokens in the NGS category (3.19 ms) (t = 7.326, P < 0.001). The results also showed that there was no significant difference in VAT values between the different combined monosyllables both in GS and in NGS group. The conclusion that can be drawn from this study is that the VAT value was sensitively decreased in cleft palate Mandarin speakers with GS comparing to those without GS., (Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Fundamental frequency (f o ) is often estimated based on electroglottographic (EGG) signals. Because of the nature of the method, the quality of EGG signals may be impaired by certain features like amplitude or baseline drifts, mains hum, or noise. The potential adverse effects of these factors on f o estimation have to date not been investigated. Here, the performance of 13 algorithms for estimating f o was tested, based on 147 synthesized EGG signals with varying degrees of signal quality deterioration. Algorithm performance was assessed through the standard deviation σ fo of the difference between known and estimated f o data, expressed in octaves. With very few exceptions, simulated mains hum, and amplitude and baseline drifts did not influence f o results, even though some algorithms consistently outperformed others. When increasing either cycle-to-cycle f o variation or the degree of subharmonics, the SIGMA algorithm had the best performance (max. σ fo  = 0.04). That algorithm was, however, more easily disturbed by typical EGG equipment noise, whereas the NDF and Praat's auto-correlation algorithms performed best in this category (σ fo  = 0.01). These results suggest that the algorithm for f o estimation of EGG signals needs to be selected specifically for each particular data set. Overall, estimated f o data should be interpreted with care., (Copyright © 2018 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Although it has been shown in previous research (Orlikoff, 1991; Henrich et al, 2005; Kuang et al, 2014; Awan, 2015) that there exists a relationship between the electroglottogram (EGG) waveform and the acoustic signal, this relationship is still not fully understood. To investigate this relationship, the EGG and acoustic signals were measured for four male amateur choir singers who each produced eight consecutive tones of increasing and decreasing vocal intensity. The EGG signals were processed cycle-synchronously to obtain the discrete Fourier transform, and the data were used as an input to a clustering algorithm. The acoustic signal was analyzed in terms of sound pressure level (dB SPL) and fundamental frequency (f o ) of vibration, and the results of both EGG and acoustic analysis were depicted on a two-dimensional plane with f o on the x-axis and SPL on the y-axis. All the subjects were seen to have a weak, near-sinusoidal EGG waveform in their lowest SPL range, whereas increase in SPL coincided with progressive enrichment in harmonic content of the EGG waveforms. The results of the clustering were additionally used to classify waveforms across subjects to enable inter-subject comparisons and assessment of individual strategies of exploring the f o -SPL dimensions. In these male subjects, the EGG waveform shape appeared to vary with SPL and to remain essentially constant with f o over one octave., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

The electroglottographic (EGG) contact quotient (CQegg), an estimate of the relative duration of vocal fold contact per vibratory cycle, is the most commonly used quantitative analysis parameter in EGG. The purpose of this study is to quantify the CQegg's relation to the closed quotient, a measure more directly related to glottal width changes during vocal fold vibration and the respective sound generation events. Thirteen singers (six females) phonated in four extreme phonation types while independently varying the degree of breathiness and vocal register. EGG recordings were complemented by simultaneous videokymographic (VKG) endoscopy, which allows for calculation of the VKG closed quotient (CQvkg). The CQegg was computed with five different algorithms, all used in previous research. All CQegg algorithms produced CQegg values that clearly differed from the respective CQvkg, with standard deviations around 20% of cycle duration. The difference between CQvkg and CQegg was generally greater for phonations with lower CQvkg. The largest differences were found for low-quality EGG signals with a signal-to-noise ratio below 10 dB, typically stemming from phonations with incomplete glottal closure. Disregarding those low-quality signals, we found the best match between CQegg and CQvkg for a CQegg algorithm operating on the first derivative of the EGG signal. These results show that the terms "closed quotient" and "contact quotient" should not be used interchangeably. They relate to different physiological phenomena. Phonations with incomplete glottal closure having an EGG signal-to-noise ratio below 10 dB are not suited for CQegg analysis., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Introduction: Recent research has revealed that classically trained tenors tend to constrict epilaryngeal structures when singing in and above the passaggio (ie, the frequency region where register events typically occur). These constrictions complicate visibility of vocal fold oscillatory patterns with transoral rigid high-speed video endoscopy, thus limiting the current understanding of laryngeal dynamics in the passaggio region of tenors., Materials and Methods: This investigation analyzed seven professionally trained western classical tenors using high-speed digital imaging (HSDI) at 20,000 frames per second via transnasal flexible endoscopy. The participants produced transitions (a) from modal to falsetto register and (b) from modal to stage voice above the passaggio (SVaP) during ascending pitch glides from A3 (220 Hz) to A4 (440 Hz) on vowel /i/. HSDI data were complemented by simultaneous acoustic and electroglottographic recordings., Results: For many subjects both transition types were associated with constrictions of the epilaryngeal structures during the pitch glide. These constrictions appeared to be more distinct for the SVaP than for falsetto. No major irregularities of vocal fold oscillations in the sense of fundamental frequency jumps were observed for either transition type. However, during the transitions, the open quotient derived from the glottal area waveform (OQ GAW ) increased; in falsetto, the OQ GAW was greater and the electroglottographic cepstral peak prominence was lower than in SVaP., Conclusions: Epilaryngeal constrictions should be considered typical for tenors singing at high fundamental frequencies. Vocal fold oscillatory patterns are changing not only for the register shift from modal to falsetto but also for the transition from modal to SVaP, indicating a need for laryngeal adjustments during these transitions., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: There is a necessity to include objective methods to the study protocol of voice. Such procedure will help not only in diagnosing and monitoring the course of treatment, but also in comparing the results of studies between research centers., Methods: Vocal fold mucosal wave characteristics of 70 healthy people were made using videostrobokymographic open quotient (VSK OQ ) and electroglottographic quasi-open quotient (EGG QOQ )., Results: Statistically significant differences were achieved regarding gender for the averaged values of VSK OQ as well as for values calculated from the posterior part of the vocal folds. A statistically significant correlation between the value of VSK OQ and age was observed for the posterior part of the glottis. Differences between gender and the value of EGG QOQ were observed. No statistically significant correlation between EGG QOQ and age was obtained., Conclusions: VSK OQ and EGG QOQ are parameters characterizing glottal function in a coherent manner. These parameters can be included easily in phoniatric examination and help to objectify glottal function., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Several historical sources from the first half of the 19th century mention a distinct third register mechanism particular to tenor voices of that period. This so-called voce faringea-often described as an "intermediate" register-is a virtually forgotten historical singing practice used to extend the upper range of the voice, where the singer modifies falsetto, typically a weak and often feminine sound, into a more powerful, tenor-like vocal quality. Based on an evaluation of historical voice register theories, training strategies, and the sound ideals of the historical period, an informed discussion of that technique is developed. For this study, acoustic and electroglottographic signals for tones produced on the vowel /a/ by a professional tenor/countertenor in different vocal register mechanisms-voce faringea, falsetto, chest register, and mezza voce-were recorded using the VoceVista system. Analysis of the electroglottography (EGG) and audio data revealed specific characteristics of the voce faringea with regard to both the laryngeal mechanism and the sound spectrum, including high EGG contact quotient and low speed quotient values. EGG pulses were skewed significantly to the left and displayed a distinct knee shape during the de-contacting phase of the vocal folds, which consequently indicates a vibration with a clear mucosal wave. The long-term average spectrum and power spectrum exposed a considerable amplification and dislocation of F 2 in the direction of high frequencies, thus boosting the third harmonic and showing a strong concentration of acoustic energy in the area of the singer's formant cluster., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to investigate electroglottography (EGG) contact quotient modulation with emotional state in the presence of increased arousal., Study Design: A within-subject reversal paradigm using multiple experimental conditions., Methods: A total of 11 healthy undergraduate students underwent emotion induction with intermittent startles to increase physiologic arousal. During emotion induction, they vocalized on the vowel /u/ while EGG was recorded., Results: EGG contact quotient was significantly greater for negative emotions compared with positive emotions with increased arousal commensurate with past research. In addition, overall EGG contact quotient was greater with elevated arousal. However, the effect sizes were small., Conclusions: EGG contact quotient appears to increase with elevated arousal and be greater for negative mood states than positive mood states confirming that emotion states directly influence vocal functioning., (Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Vocal-fold vibration can be analyzed in a noninvasive way by registering impedance changes within the glottis, through electroglottography. The morphology of the electroglottographic (EGG) signal is related to different vibratory patterns. In the literature, a characteristic knee in the descending portion of the signal has been reported. Some EGG signals do not exhibit this particular knee and have other types of events (inflection events) throughout the ascending and/or descending portion of the vibratory cycle. The goal of this work is to propose an automatic method to identify and classify these events. A computational algorithm was developed based on the mathematical properties of the EGG signal, which detects and reports events throughout the contact phase. Retrospective analysis of EGG signals obtained during routine voice evaluation of adult individuals with a variety of voice disorders was performed using the algorithm as well as human raters. Two judges, both experts in clinical voice analysis, and three general speech pathologists performed manual and visual evaluation of the sample set. The results obtained by the automatic method were compared with those of the human raters. Statistical analysis revealed a significant level of agreement. This automatic tool could allow professionals in the clinical setting to obtain an automatic quantitative and qualitative report of such events present in a voice sample, without having to manually analyze the whole EGG signal. In addition, it might provide the speech pathologist with more information that would complement the standard voice evaluation. It could also be a valuable tool in voice research., (Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: (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)., Study Design: Software development with application in a prospective controlled study., Methods: 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., Results: 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., Conclusions: 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., (Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: Electroglottography (EGG) is a widely used noninvasive method that purports to measure changes in relative vocal fold contact area (VFCA) during phonation. Despite its broad application, the putative direct relation between the EGG waveform and VFCA has to date only been formally tested in a single study, suggesting an approximately linear relationship. However, in that study, flow-induced vocal fold (VF) vibration was not investigated. A rigorous empirical evaluation of EGG as a measure of VFCA under proper physiological conditions is therefore still needed., Methods/design: Three red deer larynges were phonated in an excised hemilarynx preparation using a conducting glass plate. The time-varying contact between the VF and the glass plate was assessed by high-speed video recordings at 6000 fps, synchronized to the EGG signal., Results: The average differences between the normalized [0, 1] VFCA and EGG waveforms for the three larynges were 0.180 (±0.156), 0.075 (±0.115), and 0.168 (±0.184) in the contacting phase and 0.159 (±0.112), -0.003 (±0.029), and 0.004 (±0.032) in the decontacting phase., Discussions and Conclusions: Overall, there was a better agreement between VFCA and the EGG waveform in the decontacting phase than in the contacting phase. Disagreements may be caused by nonuniform tissue conductance properties, electrode placement, and electroglottograph hardware circuitry. Pending further research, the EGG waveform may be a reasonable first approximation to change in medial contact area between the VFs during phonation. However, any quantitative and statistical data derived from EGG should be interpreted cautiously, allowing for potential deviations from true VFCA., (Copyright © 2016 The Auhors. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose was to assess whether cervical muscular contraction during phonation influences the period and amplitude perturbation quotients (PPQ and APQ, respectively) of electroglottographic (EGG) signals, and whether high-pass filtering can attenuate these effects., Study Design: Prospective., Methods: We included 19 nondysphonic speakers and 21 patients with muscle tension dysphonia. During the recording of acoustic and EGG signals, each participant was instructed to naturally phonate sustained vowels /i:/ and /a:/ (NP tasks), and additionally, each nondysphonic participant was asked to phonate the same vowels in a nondysphonic voice quality while contracting the cervical muscles (muscular contracted phonation [MCP] tasks). To confirm the contraction, surface and needle electromyography (EMG) was performed. The EGG signals were high-pass filtered at different cutoff frequencies from 0 to 90 Hz and were subsequently analyzed for the PPQ and APQ., Results: Compared with the NP tasks, the MCP tasks enhanced the cervical EMG activities ranging from 0 to more than 1000 Hz, but conferred only low-frequency noise to the EGG signals under 50 Hz and increased the values for EGG-APQ, but not EGG-PPQ. These EGG-APQ values exhibited gradual decreases after high-pass filtering with an increase in the cutoff frequency ranging from 0 to 50 Hz in both groups, followed by plateaus during the MCP tasks in the nondysphonic group., Conclusions: The present results demonstrate that cervical muscular contraction seriously affects the EGG-APQ values for unfiltered EGG signals independent of the EMG activities and that appropriate high-pass filtering over 50 Hz can attenuate these effects., (Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: To date, only a few studies have examined the possible relationship between electroglottographic (EGG) data and spectral characteristics of the voice. This study examined the possible association between EGG signal data (contact quotient [CQ] and decontacting phase profile) and spectral moments of the acoustic signal (spectral mean, spectral standard deviation (SD), spectral skewness, and spectral kurtosis). Furthermore, the possible effects of gender on these measurements were analyzed., Methods: Sustained vowel /ɑ/ productions were obtained from 48 normophonic individuals (24 adult males and 24 adult females). The central 1-second portions of the acoustic vowel samples were analyzed for spectral moments, and the EGG signal was analyzed for CQ (CQEGG), fundamental frequency (F0), and decontacting phase profile., Results: Across all subjects, the spectral characteristics of the voice (in particular, spectral SD, skewness, and kurtosis) are significantly related to changes in the relative duration of vocal fold contact (as measured via CQEGG). In addition, significant effects of the profile of the EGG decontacting phase (ie, concave down/"knee" vs concave up/"no knee") on spectral SD were also observed, as well as a strong trend for decontacting phase profile to influence the spectral mean., Discussion: Although the degree of vocal fold contact and differences in decontacting phase profile may have an influence on the spectral characteristics of the acoustic voice signal, the strength of correlations between CQEGG values and measures of spectral moments only accounted for approximately 13-16% of the variation in spectral distribution characteristics. These results stress the importance of the transformative role of the supraglottal vocal tract in producing an acoustic output that maintains some of the characteristics of the glottal source, but which modifies the source characteristics in ways not completely accounted for by single parameters such as CQEGG or EGG profile., (Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this study was to describe changes in aerodynamic and electroglottographic (EGG) measures immediately after completing three semi-occluded vocal tract (SOVT) exercises., Study Design: Prospective case series., Methods: Aerodynamic and EGG measurements were obtained before and immediately after performing three SOVTs (straw phonation, lip trill, and tongue trill) in four singers for prepost comparisons to evaluate laryngeal changes persisting beyond the execution of SOVTs., Results: Mean air flow, sound pressure level, and EGG closed quotient tended to increase after completing SOVTs. The magnitude of change and consistency of change in measures across the SOVTs varied from subject-to-subject., Conclusions: Aerodynamic and EGG changes did occur during and immediately after completing SOVTs. However, there was marked variability within and across participants. Further investigation is needed to better understand which SOVTs are likely to benefit a particular individual., (Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: 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., Methods: 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., Results: 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., Conclusions: 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., (Copyright © 2014 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

This study examines electroglottographic (EGG) recordings for 15 young and 14 old male speakers of New Zealand English. Analysis was performed on the sustained vowels /i:/ and /a:/ at three target levels for both pitch and loudness. Jitter was greater for older speakers, and the contact quotient (Qx) was significantly lower for older speakers. The greater jitter for older speakers indicates a decrease in the stability of the vocal production mechanism of the older speakers. The jitter is an acoustic measure, so to examine the stability at a physiological level, a perturbation measure of the Qx is developed and applied to the EGG recordings. The contact quotient perturbation (CQP) showed a significant increase for older speakers (1.55% and 3.54% for young and old, respectively), and this demonstrated more about the variability than the jitter data alone. When loudness is also considered, the Qx was significantly greater for louder vowels, whereas its perturbation was significantly lower for louder vowels. This relationship combined with the age effect, with the CQP for all three loudness levels being greater for the older speakers. The findings of this study will contribute to the development of vocal fold models that account for aging., (Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.)