Glottal Area Waveform Research Articles

Vibratory onset and offset times in children: A laryngeal imaging study

ObjectivesThe aim of the study was to evaluate the differences in vibratory onset and offset times across age (adult males, adult females, and children) and waveform types (total glottal area waveform, left glottal area waveform, and right glottal area waveform) using high-speed videoendoscopy. MethodsIn this prospective study, vibratory onset and offset times were evaluated in a total of 86 participants. Forty-three children (23 girls, 18 boys) between 5 and 11 years and 43 gender matched vocally normal young adults (23 females and 18 males) in the age range (21–45 years) were recruited. Vibratory onset and offset times were calculated in milliseconds from the total, left, and right Glottal Area Waveform (GAW). A two-factor analysis of variance was used to compare the means among the subject groups (children, adult male, and adult female) and waveform type (total GAW, left GAW, right GAW) for onset and offset variables. Post hoc analyses were performed using the Fishers Least Significant Different test with Bonferroni correction for multiple comparisons. ResultsChildren exhibited significantly shorter vibratory onset and offset times compared to adult males and females. Differences in vibratory onset and offset times were not statistically significant between adult males and females. Across all waveform types (i.e. total GAW, left GAW, and right GAW), no statistical significance was observed among the subject groups. ConclusionThis is the first study reporting vibratory onset and offset times in the pediatric population. The study findings lay the foundation for the development of a large age- and gender-based database of the pediatric population to aid the study of the effects of maturation of vocal fold vibration in adulthood. The findings from this study may also provide the basis for evaluating the impact of numerous lesions on tissue pliability, and thereby has potential utility for the clinical differentiation of various lesions.

Investigation of the Immediate Effects of Humming on Vocal Fold Vibration Irregularity Using Electroglottography and High-speed Laryngoscopy in Patients With Organic Voice Disorders

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). 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. 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. 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.

Quantitative assessment of videolaryngostroboscopic images in patients with glottic pathologies

Introduction: Digital imaging techniques enable exploration of novel visualization modalities of the vocal folds during phonation and definition of parameters, facilitating more precise diagnosis of voice disorders.Aim: Application of computer vision algorithms for analysis of videolaryngostroboscopic (VLS) images aimed at qualitative and quantitative description of phonatory vibrations.Materials and methods: VLS examinations were conducted for 45 females, including 15 subjects with vocal nodules, 15 subjects with glottal incompetence, and 15 normophonic females. The recorded VLS images were preprocessed, the glottis area was segmented out, and the glottal cycles were identified. The glottovibrograms were built, and then the glottal area waveforms (GAW) were quantitatively described by computing the following parameters: open quotient (OQ), closing quotient (CQ), speed quotient (SQ), minimal relative glottal area (MRGA), and a new parameter termed closure difference index (CDI).Results: Profiles of the glottal widths assessed along the glottal length differentiated the study groups (P < 0.001). Moreover, it was shown that the OQ, CQ, CDI, and MRGA indices can be considered as viable parameters for quantifying kinematics of the vocal folds for normophonic subjects and patients with diagnosed vocal nodules and glottal incompetence (P < 0.001).Conclusions: Computer image processing and analysis methods applied to videolaryngostroboscopic images allow for their quantitative assessment. Computation of the size-related and time-related parameters characterizing glottic pathologies is of interest for evidence-based voice diagnostics. Results of the performed ROC curve analysis suggest that the evaluated parameters can distinguish patients with voice disorders from normophonic subjects.

Phasegram Analysis of Vocal Fold Vibration Documented With Laryngeal High-speed Video Endoscopy

In a recent publication, the phasegram, a bifurcation diagram over time, has been introduced as an intuitive visualization tool for assessing the vibratory states of oscillating systems. Here, this nonlinear dynamics approach is augmented with quantitative analysis parameters, and it is applied to clinical laryngeal high-speed video (HSV) endoscopic recordings of healthy and pathological phonations. HSV data from a total of 73 females diagnosed as healthy (n = 42), or with functional dysphonia (n = 15) or with unilateral vocal fold paralysis (n = 16), were quantitatively analyzed. Glottal area waveforms (GAW) and left and right hemi-GAWs (hGAW) were extracted from the HSV recordings. Based on Poincaré sections through phase space-embedded signals, two novel quantitative parameters were computed: the phasegram entropy (PE) and the phasegram complexity estimate (PCE), inspired by signal entropy and correlation dimension computation, respectively. Both PE and PCE assumed higher average values (suggesting more irregular vibrations) for the pathological as compared with the healthy participants, thus significantly discriminating healthy group from the paralysis group (P = 0.02 for both PE and PCE). Comparisons of individual PE or PCE data for the left and the right hGAW within each subject resulted in asymmetry measures for the regularity of vocal fold vibration. The PCE-based asymmetry measure revealed significant differences between the healthy group and the paralysis group (P = 0.03). Quantitative phasegram analysis of GAW and hGAW data is a promising tool for the automated processing of HSV data in research and in clinical practice.

Evaluation of Analytical Modeling Functions for the Phonation Onset Process.

The human voice originates from oscillations of the vocal folds in the larynx. The duration of the voice onset (VO), called the voice onset time (VOT), is currently under investigation as a clinical indicator for correct laryngeal functionality. Different analytical approaches for computing the VOT based on endoscopic imaging were compared to determine the most reliable method to quantify automatically the transient vocal fold oscillations during VO. Transnasal endoscopic imaging in combination with a high-speed camera (8000 fps) was applied to visualize the phonation onset process. Two different definitions of VO interval were investigated. Six analytical functions were tested that approximate the envelope of the filtered or unfiltered glottal area waveform (GAW) during phonation onset. A total of 126 recordings from nine healthy males and 210 recordings from 15 healthy females were evaluated. Three criteria were analyzed to determine the most appropriate computation approach: (1) reliability of the fit function for a correct approximation of VO; (2) consistency represented by the standard deviation of VOT; and (3) accuracy of the approximation of VO. The results suggest the computation of VOT by a fourth-order polynomial approximation in the interval between 32.2 and 67.8% of the saturation amplitude of the filtered GAW.

Which Mathematical and Physiological Formulas are Describing Voice Pathology: An Overview

This study focuses upon changes in quantifiable parameters of voice production comparing normal voices and patients with complaints of hoarseness for more than two weeks. Acoustical signals and high speed films were data sources for mathematical and physiological formulas statistics of the voices. The software ”Glottis Analysis Tools” (Erlangen, Germany) includes acoustical measurements and data sources in Glottal Area Waveforms (GAW) and Phonovibrograms (PVG), based on high speed film data. High speed film data were captured with high speed camera and software from Wolf Ltd, Germany. Data with statistical significant difference between 12 healthy voices and 12 patients with complaints of hoarse voices in a prospective case/control study were presented. The commonly used acoustical and physiological parameters showed hardly any statistical difference between the normal persons and the persons with complaints of hoarseness for more than two weeks. This suggests that evidence on physiological and acoustical measures of voice pathology is insufficient. Focus should be upon newer methods and tissue function.

Quantitative Analysis of Vocal Fold Vibration in Vocal Fold Paralysis With the Use of High-speed Digital Imaging

The goal of this work was to objectively elucidate the vibratory characteristics of vocal fold paralysis (VFP) using high-speed digital imaging (HSDI). HSDI was performed in 29 vocally healthy subjects (12 women and 17 men) and in 107 patients with VFP (40 women and 67 men). Then, the HSDI data were evaluated by visual-perceptual rating, single-line kymography, multiline kymography, laryngotopography, and glottal area waveform analysis. Patients with VFP compared with vocally healthy subjects revealed more frequent incomplete glottal closure, greater asymmetry in amplitude, mucosal wave, frequency, and phase, as well as larger open quotient, smaller speed index, larger maximal and minimal glottal area, and smaller glottal area difference. Paralyzed vocal folds in VFP revealed reduced mucosal wave than nonparalyzed vocal folds in VFP or in intact vocal folds in vocally healthy subjects. HSDI was effective in documenting the characteristics of vocal fold vibrations in patients with VFP and in exploring the vibratory disturbance for estimating the severity of dysphonia.

Visualization and Estimation of Vibratory Disturbance in Vocal Fold Scar Using High-Speed Digital Imaging

To explore the method to visualize and quantify the abnormality of vocal fold vibration in vocal fold scar (VFS) using high-speed digital imaging (HSDI). HSDI was performed on 12 patients (2 men and 10 women) with VFS and 46 vocally healthy subjects (17 men and 29 women), and the obtained data were quantitatively evaluated by frame-by-frame analysis, laryngotopography (LTG), single-line and multiline kymography, and glottal area waveform. Visualization of a scarred area was feasible in 75% of VFS in the present study using LTG. Quantitative HSDI analysis revealed that VFS had poorer glottal closure (eg, larger open quotients, larger minimal glottal area), reduced vibration in a scarred area (eg, smaller mucosal wave magnitude, mucosal wave persistence, lateral peak index), and greater asymmetry (eg, amplitude difference, mucosal wave magnitude difference, lateral phase difference) than the control group. Correlation study revealed moderate correlations between HSDI-derived parameters and conventional acoustic or aerodynamic parameters (eg, period perturbation quotient). HSDI is considered to be useful in the diagnosis of VFS, visualization of a scarred area, and quantification of vibratory abnormality.

Preliminary Study of the Open Quotient in an Ex Vivo Perfused Human Larynx.

Scientific understanding of human voice production to date is a product of indirect investigations including animal models, cadaveric tissue study, or computational modeling. To our knowledge, direct experimentation of human voice production has previously not been possible owing to its invasive nature. The feasibility of an ex vivo perfused human phonatory model has recently allowed systematic investigation in virtually living human larynges with parametric laryngeal muscle stimulation. To investigate the association between adductor muscle group stimulation and the open quotient (OQ) (the fraction of the cycle during which the glottis remains open) of vocal fold vibration. An ex vivo perfused human tissue study was conducted at a physiology laboratory. Human larynx recovered from organ donors within 2 hours of cardiac death was used. The study was performed on May 19, 2014; data analysis took place from June 1, 2014, to December 15, 2014. Perfusion with donated human blood was reestablished shortly after cardiac death. Ex vivo perfused human phonation was then achieved by providing subglottal airflow under graded neuromuscular electrical stimulation bilaterally to the intrinsic adductor groups and cricothyroid muscles. Phonation resulting from the graded states of neuromuscular stimulation was evaluated using high-speed vibratory imaging; the OQ was derived through digital kymography and glottal area waveform analysis. During constant glottal flow, a stepwise increase in adductor muscle group stimulation decreased the OQ. Quantitatively, OQ values decreased with increased stimulation levels from 2 V (OQ, 1) to 5 V (OQ, 0.68) and reached a lower limit of 8 V (OQ, 0.42). Increased stimulation above maximal muscle deformation was unable to affect OQ beyond this lower limit. To our knowledge, a negative association between adductor muscle group stimulation and phonatory OQ has been demonstrated for the first time in a neuromuscularly activated human larynx. Further experience with the ex vivo perfused human phonatory model will aid in systematically defining this causal relationship.

Quantification of Vocal Fold Vibration in Various Laryngeal Disorders Using High-Speed Digital Imaging

To quantify vibratory characteristics of various laryngeal disorders seen by high-speed digital imaging (HSDI). HSDI was performed on 78 patients with various laryngeal disorders (20 with polyp, 16 with carcinoma, 13 with leukoplakia, 6 with vocal fold nodule, and 33 with others) and 29 vocally healthy subjects. Obtained data were quantitatively evaluated by frame-by-frame analysis, laryngotopography, digital kymography, and glottal area waveform. Overall, patients with laryngeal pathologies showed greater asymmetry in amplitude, mucosal wave and phase, smaller mucosal wave, and poorer glottal closure than vocally healthy subjects. Furthermore, disease-specific vibratory disturbances that generally agreed with the findings in the literature were quantified: comparing polyp with nodule, differences were noted in longitudinal phase difference, amplitude, and mucosal wave. In comparison with leukoplakia and cancer, nonvibrating area was more frequently noted in cancer. The HSDI analysis of various voice disorders using multiple methods can help phonosurgeons to properly diagnose various laryngeal pathologies and to estimate the degree of their vocal disturbances.

Vocal Fold Vibration in Vocal Fold Atrophy: Quantitative Analysis With High-Speed Digital Imaging

Vocal fold vibrations of vocal fold atrophy (VFA), a rapidly increasing voice disorder owing to worldwide societal aging, have not been clarified by high-speed digital imaging (HSDI). The HSDI method was performed on 46 patients (33 males and 13 females) with VFA and 20 vocally healthy subjects (8 males and 12 females), and the obtained data were quantitatively evaluated by frame-by-frame analysis, laryngotopography, single- and multi-line kymography, and glottal area waveform. Overall, patients with VFA revealed larger open quotients, larger lateral phase difference, larger integral glottal width (the average glottal width over a glottal cycle), and smaller speed index than vocally healthy subjects. Some gender difference was noted: in males, lateral phase difference was not significant; and in females, integral glottal width and speed index were not significant. Correlation study revealed moderate correlations between HSDI-derived parameters and conventional acoustic or aerodynamic parameters. The combination of multiple HSDI analysis methods was effective in documenting the characteristics of vocal fold vibrations in VFA. The knowledge of general vibratory characteristics and gender difference is beneficial for the appropriate clinical care of VFA.

A Study of Injection Therapy Using bFGF by High‐Speed Imaging and Acoustic Analysis

Objectives: Some authors have reported effects of some materials used for injection. Their effects that reduce the size of glottal gap do not last because the materials are usually absorbed. Thus, patients with deficient glottal closure must be repeatedly injected. To reduce the number of treatments, we injected basic fibroblast growth factor (bFGF) into our patients. The purpose of this study was to examine the effect of bFGF injection by high-speed imaging and acoustic analysis. Methods: Fifteen patients (8 men and 7 women, mean age 65 years) were enrolled in this study. Four or 8 µg of bFGF were injected into each treated vocal cord. The injection was made into the unilateral or bilateral vocal cord according to the size of glottal gap. All patients were followed up every 3 months. Using high-speed imaging and PS77E, we analyzed the following factors: KEA (kimograph edge analysis), GAW (glottal area wave form), phase shift analysis, PPQ (period pertubation quotient), APQ (amplitude perturbation quotient), MFR (mean flow rates). The effect of the treatment was assessed by high-speed imaging and acoustic analysis. Results: Data both from the imaging analysis and acoustic analysis showed significant improvement in all subjects after 6 months. No allergic or long-term adverse effects were noted. Conclusions: The result of this study suggests bFGF may be effective long-term and safe as a regenerative agent for aged vocal folds.

Automatic recognizing of vocal fold disorders from glottis images.

The laryngeal video stroboscope is an important instrument to test glottal diseases and read vocal fold images and voice quality for physician clinical diagnosis. This study is aimed to develop a medical system with functionality of automatic intelligent recognition of dynamic images. The static images of glottis opening to the largest extent and closing to the smallest extent were screened automatically using color space transformation and image preprocessing. The glottal area was also quantized. As the tongue base movements affected the position of laryngoscope and saliva would result in unclear images, this study used the gray scale adaptive entropy value to set the threshold in order to establish an elimination system. The proposed system can improve the effect of automatically captured images of glottis and achieve an accuracy rate of 96%. In addition, the glottal area and area segmentation threshold were calculated effectively. The glottis area segmentation was corrected, and the glottal area waveform pattern was drawn automatically to assist in vocal fold diagnosis. When developing the intelligent recognition system for vocal fold disorders, this study analyzed the characteristic values of four vocal fold patterns, namely, normal vocal fold, vocal fold paralysis, vocal fold polyp, and vocal fold cyst. It also used the support vector machine classifier to identify vocal fold disorders and achieved an identification accuracy rate of 98.75%. The results can serve as a very valuable reference for diagnosis.

Spatiotemporal Analysis of High-Speed Videolaryngoscopic Imaging of Organic Pathologies in Males

The aim of this study was to identify parameters that would differentiate healthy from pathological organic-based vocal fold vibrations to emphasize clinical usefulness of high-speed imaging. Fifty-five men (M age = 36 years, SD = 20 years) were examined and separated into 4 groups: 1 healthy (26 individuals) and 3 pathological (10 individuals with contact granuloma, 12 with polyps, and 7 with cysts). Vocal fold vibrations were recorded using a high-speed camera during sustained phonation. Twenty objective glottal area waveform and 24 phonovibrogram parameters representing spatiotemporal characteristics were analyzed. Statistical group comparisons were performed to document spatiotemporal changes for organic lesions that cannot be determined visually. To look for specific pattern profiles within organic lesions, the authors performed linear discriminant analysis. Thirteen parameters showed significant differences between the healthy group and at least 1 pathological group. The differences occurred more in temporal than in spatial parameters. Contact granuloma showed the fewest statistical differences (3 parameters), followed by cysts (9 parameters), and polyps (10 parameters). Linear discriminant analysis achieved accuracy performance of 76% (all groups separated) and 82% (healthy vs. pathological). The results suggest that for males, the differences between healthy voices and organic voice disorders may be more pronounced within temporal characteristics that cannot be visually detected without high-speed imaging.

Objective Quantification of Pre- and Postphonosurgery Vocal Fold Vibratory Characteristics Using High-Speed Videoendoscopy and a Harmonic Waveform Model

The model-based quantitative analysis of high-speed videoendoscopy (HSV) data at a low frame rate of 2,000 frames per second was assessed for its clinical adequacy. Stepwise regression was employed to evaluate the HSV parameters using harmonic models and their relationships to the Voice Handicap Index (VHI). Also, the model-based HSV parameters were compared with those using conventional analysis techniques. Eight pairs of HSV recordings of vocal folds before and after surgery for benign lesions were investigated. Five glottal area waveform features-fundamental frequency (F0), open quotient (OQ), speed index (SI), relative glottal gap (RGG), and harmonics-to-noise ratio (HNR)-were measured using model-based and conventional approaches. The statistical analyses were conducted on the mean (M) and standard deviation (SD) of the feature measurements over 1 s during sustained phonation. Two model-based HSV parameters, OQ M (ρ = .67) and HNR M (ρ = -.56), were selected and explained 55% of the VHI variation. The conventional techniques yielded a regression model with OQ SD (ρ = -.60) and F0 SD (ρ = .44), explaining 61% of the VHI variation. Although the selected model-based HSV parameters explained less variation in the VHI than the conventionally computed HSV parameters, the behaviors of the model-based parameters were more consistent with expectations and theory than the conventional analysis techniques.

Age- and Gender-Related Difference of Vocal Fold Vibration and Glottal Configuration in Normal Speakers: Analysis With Glottal Area Waveform

Glottal area waveform (GAW) analysis is widely used in the assessment of vocal fold vibration by high-speed digital imaging (HSDI). Because normative GAW data obtained from a large number of subjects have not been reported, we conducted a prospective study to obtain normative results for GAW analysis of HSDI findings and clarify normal variations associated with gender and age. Vocally healthy adults were divided into a young group (aged≤35years) and an elderly group (aged≥65years). The configuration and size of the glottal area were assessed at different phases of the glottal cycle, and gender- and age-related differences were evaluated. A total of 26 young subjects (nine men and 17 women; mean age: 27years) and 20 elderly subjects (eight men and 12 women; mean age: 73years) were investigated. The glottal area at different points of the glottal cycle showed a negative correlation with frequency. Although the GAW parameters of young women appeared to be different from those of the other subgroups, the differences were not statistically significant. Young women predominantly had a triangular- or vase-shaped glottal configuration at all frequencies, whereas the other subgroups showed various glottal shapes. The present study clarified gender- and age-related differences of GAW parameters obtained with HSDI. Young women were likely to show different glottal configurations and different responses to frequency changes from those of young men, elderly men, and elderly women. Phonosurgeons should pay attention to the normal variations detected in the present study.

Characterizing Vibratory Kinematics in Children and Adults With High-Speed Digital Imaging

PURPOSE The aim of this study is to quantify and identify characteristic vibratory motion in typically developing prepubertal children and young adults using high-speed digital imaging. METHOD The vibrations of the vocal folds were recorded from 27 children (ages 5-9 years) and 35 adults (ages 21-45 years), with high speed at 4,000 frames per second for sustained phonation. Kinematic features of amplitude periodicity, time periodicity, phase asymmetry, spatial symmetry, and glottal gap index were analyzed from the glottal area waveform across mean and standard deviation (i.e., intercycle variability) for each measure. RESULTS Children exhibited lower mean amplitude periodicity compared to men and women and lower time periodicity compared to men. Children and women exhibited greater variability in amplitude periodicity, time periodicity, phase asymmetry, and glottal gap index compared to men. Women had lower mean values of amplitude periodicity and time periodicity compared to men. CONCLUSION Children differed both spatially but more temporally in vocal fold motion, suggesting the need for the development of children-specific kinematic norms. Results suggest more uncontrolled vibratory motion in children, reflecting changes in the vocal fold layered structure and aero-acoustic source mechanisms.

On transition between voice registers: Data from high-speed laryngeal videoendoscopy

How specific aspects of vocal fold vibration alter voice register has long been a subject of interest. Transitions between vocal registers are often studied using dynamic vocal fold models and electroglottographic signals. Although laryngeal high-speed videoendoscopy has also been applied to study steady-state voice registers, there has been little such investigation on the transitions between registers. In this study, we examined voice register transitions using phonations in which vocal qualities varied continuously in fundamental frequency (F0), loudness, or voice quality (from breathy to pressed). Glottal area measures {open quotient and alternating-current to open quotient ratios [Chen et al., JASA 133, 1656–1666 (2013)]} and acoustic measures (F0, energy, and H1-H2) were studied using simultaneously collected laryngeal high-speed videoendoscopy and audio recordings from 15 subjects. The video recordings were collected transorally at 10 000 frames per second. Glottal area waveforms were extracted using GlotAnTools (Version 5) [Erlangen, Germany], and acoustic measures were gathered using VoiceSauce software and analysis-by-synthesis. Glottal area measures were compared to acoustic measures and their relationships to voice register transitions were explored.

Glottal opening and closing events investigated by electroglottography and super-high-speed video recordings

Previous research has suggested that the peaks in the first derivative (dEGG) of the electroglottographic (EGG) signal are good approximate indicators of the events of glottal opening and closing. These findings were based on high-speed video (HSV) recordings with frame rates 10 times lower than the sampling frequencies of the corresponding EGG data. The present study attempts to corroborate these previous findings, utilizing super-HSV recordings. The HSV and EGG recordings (sampled at 27 and 44 kHz, respectively) of an excised canine larynx phonation were synchronized by an external TTL signal to within 0.037 ms. Data were analyzed by means of glottovibrograms, digital kymograms, the glottal area waveform and the vocal fold contact length (VFCL), a new parameter representing the time-varying degree of 'zippering' closure along the anterior-posterior (A-P) glottal axis. The temporal offsets between glottal events (depicted in the HSV recordings) and dEGG peaks in the opening and closing phase of glottal vibration ranged from 0.02 to 0.61 ms, amounting to 0.24-10.88% of the respective glottal cycle durations. All dEGG double peaks coincided with vibratory A-P phase differences. In two out of the three analyzed video sequences, peaks in the first derivative of the VFCL coincided with dEGG peaks, again co-occurring with A-P phase differences. The findings suggest that dEGG peaks do not always coincide with the events of glottal closure and initial opening. Vocal fold contacting and de-contacting do not occur at infinitesimally small instants of time, but extend over a certain interval, particularly under the influence of A-P phase differences.

Measurement of Glottal Cycle Characteristics Between Children and Adults: Physiological Variations

The aim of this study was to quantify phases of the vibratory cycle using measurements of glottal cycle quotients and glottal cycle derivatives, in typically developing prepubertal children and young adults with the use of high-speed digital imaging (HSDI). Vocal fold vibrations were recorded from 27 children (age range 5-9 years) and 35 adults (age range 21-45years), with HSDI at 4000 frames per second for sustained phonation. Glottal area waveform measures of Open Quotient, Closing Quotient, Speed Index (SI), Rate Quotient, and Asymmetry Quotient (AsyQ) were computed. Glottal cycle derivatives of Amplitude Quotient (AQ) and Maximum Area Declination Rate (MADR) were also computed. Group differences (adult females, adult males, and children) were statistically investigated for mean and standard deviation values of the glottal cycle quotients and glottal cycle derivatives. Children exhibited higher values of SI and AsyQ and lower values of MADR compared with adult males. Children exhibited the highest mean value and lowest variability in AQ compared with adult males and females. Adult males showed lower values of SI, AsyQ, AQ, and higher values of MADR compared with adult females. Glottal cycle vibratory motion in children is functionally different compared with adult males and females, suggesting the need for development of children specific norms for both normal and disordered voice qualities.