Pathological Phonation Research Articles

Identification and analysis of Nonlinear behaviors of vocal fold biomechanics during phonation to assess efficacy of surgery for benign laryngeal Diseases

BackgroundCurrent voice assessments focus on perceptive evaluation and acoustic analysis. The interaction of vocal tract pressure (PVT) and vocal fold (VF) vibrations are important for volume and pitch control. However, there are currently little non-invasive ways to measure PVT. Limited information has been provided by previous human trials, and interactions between PVT and VF vibrations and the potential clinical application remain unclear. Here, we propose a non-invasive method for monitoring the nonlinear characteristics of PVT and VF vibrations, analyze voices from pathological and healthy individuals, and evaluate treatment efficacy. MethodHealthy volunteers and patients with benign laryngeal lesions were recruited for this study. PVT was estimated using an airflow interruption method, VF vibrational frequency was calculated from accelerometer signals, and nonlinear relationships between PVT and VF vibrations were analyzed. Results from healthy volunteers and patients, as well as pre- and post-operation for the patients, were compared. ResultsFor healthy volunteers, nonlinearity was exhibited as an initial increase and then prompt decrease in vibrational frequency at the end of phonation, coinciding with PVT equilibrating with the subglottal pressure upon airflow interruption. For patients, nonlinearity was present throughout the phonation period pre-operatively, but showed a similar trend to healthy volunteers post-operatively. ConclusionThis novel method simultaneously monitors PVT and VF vibration and helps clarify the role of PVT. The results demonstrate differences in nonlinear characteristics between healthy volunteers and patients, and pre-/post-operation in patients. The method may serve as an analysis tool for clinicians to assess pathological phonation and treatment efficacy.

Electroglottographic and Acoustic Parametrization of Phonatory Quality Provide Voice Profiles of Pathological Speakers

The present study firstly tries to find subgroups of pathological male and female phonation using data from a number of 534 pathological speakers. Secondly, this subgroup classification provides a basis for achieving voice profiles of pathological phonatory quality. Using complementarily orientated electroglottographic and acoustic parametrization of phonatory quality, sustained vowel productions of 267 male and 267 female speakers were considered. In a first step, a clustering technique differentiates three subgroups within each gender on the basis of the EGG- and three subgroups on the basis of the acoustic parameters. In a second step, this subgroup definition allows one to present voice profiles of pathological speakers by combining the parameter means of the electroglottographically determined subgroups with those of the acoustically determined subgroups. The presented voice profiles provide a finer reference basis for the classification of different pathological phonation types as well as for the evaluation of shifts in individual phonatory behavior due to therapy or spontaneous recovery.

Impact of the Paraglottic Space on Voice Production in an MRI-Based Vocal Fold Model

While the vocal fold is in direct contact anteriorly with the thyroid cartilage, posteriorly the vocal fold connects to the thyroid cartilage through a soft tissue layer in the paraglottic space. Currently the paraglottic space is often neglected in computational models of phonation, in which a fixed boundary condition is often imposed on the lateral surface of the vocal fold. The goal of this study was to investigate the effect of the paraglottic space on voice production in an MRI-based vocal fold model, and how this effect may be counteracted by vocal fold stiffening due to laryngeal muscle activation. Parametric simulation study using an MRI-based computational vocal fold model. The results showed that the presence of the paraglottic space increased the mean and amplitude of the glottal area waveform, decreased the phonation frequency and closed quotient. For the particular vocal fold geometry used in this study, the presence of the paraglottic space also reduced the occurrence of irregular vocal fold vibration. These effects of the paraglottic space became smaller with increasing paraglottic space stiffness and to a lesser degree with vocal fold stiffening. The results suggest that the paraglottic space may be neglected in qualitative evaluations of normal phonation, but needs to be included in simulations of pathological phonation or vocal fold posturing.

Quantitative Analysis of Healthy and Pathological Vocal Fold Vibrations using an Optical Flow based Waveform

The objective assessment of the vocal fold vibrations is important in diagnosing several vocal diseases. Given the high speed of the vibrations, the high speed videoendoscopy is commonly used to capture the vocal fold movements into video recordings. Commonly, two steps are carried out in order to automatically quantify laryngeal parameters and assess the vibra-tions. The first step aims to map the spatial-temporal information contained in the video recordings into a representation that facilitates the analysis of the vibrations. Numerous techniques are reported in the literature but the majority of them require the segmentation of all the images of the video, which is a complex task. The second step aims to quantify laryngeal parameters in order to assess the vibrations. To this aim, most of the existing approaches require an additional processing to the representation in order to deduce those parameters. Furthermore, for some reported representations, the assessment of the symmetry and the periodicity of the vocal fold dynamics needs setting up parameters that are specific to the representation under consideration; which makes difficult the comparison between the existing techniques. To alleviate these problems, the present study investigates the use of a recently proposed representation named optical flow based waveform, in order to objectively quantify the laryngeal parameters. This waveform is retained in this study as it does not require the segmentation of all the images of the video. Furthermore, it will be shown in the present work that the automatic quantification of the vibrations using this waveform can be carried out without applying any additional processing. Moreover, common laryngeal parameters are exploited; hence, no specific parameters are needed to be defined for the automatic assessment of the vibrations. Experiments conducted on healthy and pathological phonation show the accuracy of the waveform. Besides, it is more sensitive to pathological phonation than the state-of-the-art techniques.

Threshold of oscillation of a vocal fold replica with unilateral surface growths.

Among vocal fold diseases, the presence of a surface growth is often encountered and can be considered a public health issue. While more energy is required to achieve phonation than in healthy cases, this situation can lead to a wide range of voice perturbations, from a change of voice quality to aphonia. The present study aims at providing finer comprehension of the physical phenomena underlying this type of pathological phonation process. A vocal fold replica is used to perform measurements of mechanical responses of each vocal fold as well as of the subglottal pressure in both healthy and pathological configurations. Besides these physical measurements, a theoretical model is derived, using the one-mass-delayed model involving asymmetry of mass and geometry in order to simulate pressure signals. The theoretical model parameters are determined according to mechanical measurements on the replica. Results from measurements and simulations show that this unique vocal fold replica behaves in a manner comparable to clinical observations. The energy required to produce sound increases in the presence of a growth as well as with the size of the growth. Further investigation tends to show that the contact of the growth on the opposite vocal fold, considered as additional damping, plays a critical role.

Modeling the effects of a posterior glottal opening on vocal fold dynamics with implications for vocal hyperfunction.

Despite the frequent observation of a persistent opening in the posterior cartilaginous glottis in normal and pathological phonation, its influence on the self-sustained oscillations of the vocal folds is not well understood. The effects of a posterior gap on the vocal fold tissue dynamics and resulting acoustics were numerically investigated using a specially designed flow solver and a reduced-order model of human phonation. The inclusion of posterior gap areas of 0.03-0.1 cm(2) reduced the energy transfer from the fluid to the vocal folds by more than 42%-80% and the radiated sound pressure level by 6-14 dB, respectively. The model was used to simulate vocal hyperfucntion, i.e., patterns of vocal misuse/abuse associated with many of the most common voice disorders. In this first approximation, vocal hyperfunction was modeled by introducing a compensatory increase in lung air pressure to regain the vocal loudness level that was produced prior to introducing a large glottal gap. This resulted in a significant increase in maximum flow declination rate and amplitude of unsteady flow, thereby mimicking clinical studies. The amplitude of unsteady flow was found to be linearly correlated with collision forces, thus being an indicative measure of vocal hyperfunction.

Acoustic- and EGG-parametrisations of Phonatory Quality Provide Voice Profiles of Normal Speakers

The present study deals with the dimensions of normal phonation. It is generally accepted that there exists a wide range of normal voices. Using complementarily orientated electroglottografic and acoustic parametrisations of phonation quality, sustained vowel productions of 267 male and 267 female speakers without any reported voice pathology were analysed. A clustering technique serves to differentiate gender specific subgroups of normal phonation on the basis of these analysis results. Firstly, 3 subgroups within each gender on the basis of the EGG, and 3 subgroups on the basis of the acoustic parameters are presented. Secondly, this subgroup definition allows one to present voice profiles of normal speakers by combining the parameter means of the electroglottografically determined subgroups with those of the acoustically determined subgroups. The present voice profiles can be used as a reference and are aimed at providing a firmer basis for the classification of different normal and pathological phonation types as well as for the evaluation of shifts in individual phonation behaviour due to therapy or spontaneous recovery.

Nonlinearities in block-type reduced-order vocal fold models with asymmetric tissue properties

Modeling the vocal fold structure as a reduced-order system is an attractive approach for exploring the dynamics of both normal and pathological phonation. This approach has been used ubiquitously in scientific speech investigations due to its relatively high order of accuracy and low computational cost. In addition, good agreement can also be found between model and clinical data. In the case of pathological speech complex vocal fold dynamics may exist, exhibiting phenomenon such as bifurcation and chaos. The ability to capture these features in reduced-order vocal fold models is a much celebrated feature. However, the question has arisen whether these nonlinearities arise due to the physics, or if they are merely an artifact of the model and its sensitivity to initial and boundary conditions. We explore the sensitivity of commonly-employed reduced-order vocal fold models to both contact mechanics, and the geometric prescription of the vocal fold model. Nonlinearities arising from asymmetric vocal fold tensioning are investigated. Nonlinearity in the vocal fold dynamics is identified by determining the predictive capability of linear and nonlinear Volterra-Weiner-Korenberg series. Nonlinearities in the vocal fold oscillations are shown to be highly dependent upon model formulation and implementation, as opposed to physical features of speech.

Effects of the Voice over Internet Protocol on Perturbation Analysis of Normal and Pathological Phonation

Objective: In this study, a Voice over Internet Protocol (VoIP) communication based on G.729 protocol was simulated to determine the effects of this system on acoustic perturbation parameters of normal and pathological voice signals. Patients and Methods: Fifty recordings of normal voice and 48 recordings of pathological voice affected by laryngeal paralysis were transmitted through a VoIP communication system. The acoustic analysis programs of CSpeech and MDVP were used to determine the percent jitter and percent shimmer from the voice samples before and after VoIP transmission. The effects of three frequently used audio compression protocols (MP3, WMA, and FLAC) on the perturbation measures were also studied. Results: It was found that VoIP transmission disrupts the waveform and increases the percent jitter and percent shimmer of voice samples. However, after VoIP transmission, significant discrimination between normal and pathological voices affected by laryngeal paralysis was still possible. It was found that the lossless compression method FLAC does not exert any influence on the perturbation measures. The lossy compression methods MP3 and WMA increase percent jitter and percent shimmer values. Conclusion: This study validates the feasibility of these transmission and compression protocols in developing remote voice signal data collection and assessment systems.

Phonation threshold flow measurements in normal and pathological phonation

Phonation threshold flow (PTF) may provide a tool to assess laryngeal function and could differentiate between normal and pathological voices. Both polyps and nodules contribute to an increased PTF by creating an incomplete glottal closure and increased vocal fold mass and thickness. Prospective study. The Kay Elemetrics Phonatory Aerodynamic System (PAS) (Kay Elemetrics Corp., Lincoln Park, NJ) was used to collect mean flow rate (MFR) and PTF measurements from 40 normal subjects, 21 patients with vocal fold nodules, and 23 patients with vocal fold polyps. Gender-based differences were assessed using a t test. The effect of vocal pathology on PTF and MFR was determined with an ANOVA. Diagnostic potential was evaluated using a receiver operation characteristics (ROC) analysis. Both PTF (P = .047) and MFR (P = .008) were significantly affected by gender. Using a two-way ANOVA and correcting for gender differences, the influence of pathology on PTF was determined to be significant (P < .001). Post hoc tests found a significant difference between normal and polyp subjects (P < .001) but not normal and nodule subjects (P = .177) or nodule and polyp subjects (P = .246). ROC analysis found that PTF (area under the curve [AUC] = 0.691) and MFR (AUC = 0.684) had a similar diagnostic utility. PTF can be used to differentiate between normal and pathological voices. As a parameter that is experimentally sensitive to the biomechanical parameters providing its theoretical basis, it could be used clinically to analyze laryngeal functionality. Future research could focus on measuring PTF in other pathologies, such as paralysis or scarring, which would also affect the effort required to produce voice.

Phonation Threshold Flow Measurements in Normal and Pathological Phonation

The LaryngoscopeVolume 119, Issue S3 p. S279-S279 Triological Society 2009 Annual Meeting Poster Session Phonation Threshold Flow Measurements in Normal and Pathological Phonation Peiyun Zhuang MD, Peiyun Zhuang MD University of Wisconsin-Madison School of Medicine and Public Health ENT Department, Xiamen University, Xiamen, ChinaSearch for more papers by this authorAlicia J. Sprecher BS, Alicia J. Sprecher BS University of Wisconsin-Madison School of Medicine and Public HealthSearch for more papers by this authorMatthew R. Hoffman BS, Matthew R. Hoffman BS University of Wisconsin-Madison School of Medicine and Public HealthSearch for more papers by this authorYi Zhang MD, Yi Zhang MD EENT Hospital of FudanUniversity, Shanghai, ChinaSearch for more papers by this authorMarios Fourakis PhD, Marios Fourakis PhD University of Wisconsin-Madison School of Medicine and Public HealthSearch for more papers by this authorJack J. Jiang MD, PhD, Jack J. Jiang MD, PhD University of Wisconsin-Madison School of Medicine and Public Health EENT Hospital of FudanUniversity, Shanghai, ChinaSearch for more papers by this authorChungsheng Wei MD, Chungsheng Wei MD EENT Hospital of FudanUniversity, Shanghai, ChinaSearch for more papers by this author Peiyun Zhuang MD, Peiyun Zhuang MD University of Wisconsin-Madison School of Medicine and Public Health ENT Department, Xiamen University, Xiamen, ChinaSearch for more papers by this authorAlicia J. Sprecher BS, Alicia J. Sprecher BS University of Wisconsin-Madison School of Medicine and Public HealthSearch for more papers by this authorMatthew R. Hoffman BS, Matthew R. Hoffman BS University of Wisconsin-Madison School of Medicine and Public HealthSearch for more papers by this authorYi Zhang MD, Yi Zhang MD EENT Hospital of FudanUniversity, Shanghai, ChinaSearch for more papers by this authorMarios Fourakis PhD, Marios Fourakis PhD University of Wisconsin-Madison School of Medicine and Public HealthSearch for more papers by this authorJack J. Jiang MD, PhD, Jack J. Jiang MD, PhD University of Wisconsin-Madison School of Medicine and Public Health EENT Hospital of FudanUniversity, Shanghai, ChinaSearch for more papers by this authorChungsheng Wei MD, Chungsheng Wei MD EENT Hospital of FudanUniversity, Shanghai, ChinaSearch for more papers by this author First published: 11 January 2011 https://doi.org/10.1002/lary.21537AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume119, IssueS3Supplement: Triological Society 2009 Annual Meeting Poster Session2009Pages S279-S279 RelatedInformation

Intraglottal pressure distributions for oblique glottal angles

Asymmetric vocal fold oscillation occurs for both normal and pathological phonation. The pressures on the right and left glottal walls receive different pressures when the glottis is oblique, as we have shown previously. Different driving forces may affect the motion, although to what extent is not yet known. We have continued empirical modeling of various oblique glottal shapes using a Plexiglas model (M5), and report the findings of those studies. In general, an oblique glottis tends to receive higher pressures on the more convergent side, and the cross-channel pressure differences may shift polarity between upstream and downstream sections. The effects on intraglottal pressures for a wide range of obliquity, minimal glottal diameter, transglottal pressure, and included glottal angle will be shown and discussed relative to potential oscillatory effects. [supported by NIH R01DC03577]

Instrumental dimensioning of normal and pathological phonation using acoustic measurements

The present study deals with the dimensions of normal and pathological phonation. Separation of normal voices from pathological voices is tested under different aspects. Using a new parametrization of voice‐quality properties in the acoustic signal, the vowel productions of 534 speakers (267 M, 267 F) without any reported voice pathology and the productions of 534 gender‐matched pathological speakers were considered. In a first step, a gender‐specific separation of the two groups is supported by a number of significantly different parameter means. In a second step, a clustering technique differentiates three subgroups within each group and gender on the basis of the acoustic parameters. Further, a statistical examination of the correct assignment in the database (DB‐classification) as “normal” or “pathological” shows that the two groups overlap to some extent. The overlap of speaker assignment indicates a phonation continuum through the multidimensional space extending from normal to pathological voices. The validity of a categorical distinction of normal and pathological phonation in the sense of an individual or group‐orientated labelling of voice quality as “normal” or “pathological”, respectively, is discussed.

Chaos in Voice, From Modeling to Measurement

Chaos has been observed in turbulence, chemical reactions, nonlinear circuits, the solar system, biological populations, and seems to be an essential aspect of most physical systems. Chaos may also be central to the interpretation of irregularity in voice disorders. This presentation will summarize the results from a series of our recent studies. These studies have demonstrated the prescence of chaos in computer models of vocal folds, experiments with excised larynges, and human voices. Methods based on nonlinear dynamics can be used to quantify chaos and irregularity in vocal fold vibration. Studies have suggested that disordered voices from laryngeal pathologies such as laryngeal paralysis, vocal polyps, and vocal nodules might exhibit chaotic behaviors. Conventional parameters, such as jitter and shimmer, may be unreliable for analysis of periodic and chaotic voice signals. Nonlinear dynamic methods, however, have differentiated between normal and pathological phonations and can describe the aperiodic or chaotic voice. Chaos theory and nonlinear dynamics can enchance our understanding and therefore our assessment of pathological phonation.

Detecting synchronizations in an asymmetric vocal fold model from time series data

A nonlinear modeling approach is presented for the reconstruction of the synchronization structure in an asymmetric two-mass model from time series data. The asymmetric two-mass model describes a variety of normal and pathological human voices associated with synchronous and desynchronous oscillations of the two asymmetric vocal folds. Our technique recovers the synchronization diagram, which yields the regimes of synchronization as well as desynchronization, which are dependent upon the asymmetry parameter and the subglottal pressure. This allows the prediction of the regime of pathological phonation associated with desynchronization of the vocal folds from a few sets of recorded time series. It is shown that the modeling is quite effective when the time series data are chaotic and if they are taken from a regime of desynchronization. We discuss the applicability of the present approach as a diagnostic tool for voice pathologies.

Dysphonia in infants

The definition of infant dysphonia is difficult because the physiological phonation itself may be extremely variable in newborns. In a wider sense, all voice utterings can be interpreted as dysphonia which deviate continuously in any of the parameters (timbre, pitch, intensity, or noise) from the normal. We differentiated 20 types of such pathological phonation. The most characteristic are: the hoarse (caused by inflammation or tumor of the vocal cords); the hollow (indicative of tracheal stenosis); the shrill (suggesting a CNS damage); the bleating (pathognostic of Down syndrome); the faint (a result of myogenic diseases); and the mewing cry (etiology: cri-du-chat syndrome). In a narrower sense dysphonia in infants is a kind of pathological phonation without evidence of neurological alteration or chromosomal aberration and without a verified laryngeal lesion. These infants utter pressed, harsh, or very high voice (hyperfunctional form) or a weak, inert cry (hypofunctional form). The dysphonic voice may be characterized also by sudden change in melody or in pitch (glide, shift, break, bitonality) and by turbulent noises. This type of newborn dysphonia is a result of the immature innervation of the larynx, it gradually improves and lateron spontaneously disappears. Perceptual evaluation, endoscopy, and acoustic analysis yield useful diagnostic information.

Integrated analyzer and classifier of glottographic signals.

Electroglottography (EGG) and photoglottography (PGG) are two plausible methods to study voice production for monitoring the patterns of laryngeal vibrations. It has been suggested that measures such as open quotient and speed quotient calculated from glottographic signals can provide useful information regarding pathological phonation. In this paper, an integrated analyzer and classifier of glottographic signals was implemented. The system makes it possible to calculate the measures from digitized EGG and PGG signals automatically in order to examine vocal fold abnormality. The system developed several techniques to extract features from glottographic signals and proposed a statistical classification method that can possibly aid the diagnosis process. To check the reliability of the system, a training set and a test set of glottographic signals from normal people and patients with recurrent/superior laryngeal paralysis were analyzed and classified by the system. The results showed that the system is a useful tool for quantitative study of phonatory pathophysiology and can be used by the examiner who is interested in the clinical examination of glottographic signals. Moreover, glottographic techniques may have some clinical applications in the quantitative documentation of phonatory function in patients with voice disorders but requires further evaluation before clinical application.

LF source model adequacy for pathological voices

The adequacy with which source models describe pathological phonation has been little studied, and the perceptual importance of deviations from a perfect model fit remains unknown. To address these issues, pathological voices were selected randomly from a library of samples. Glottal source waveforms were estimated by inverse filtering airflow signals. Formant frequencies and bandwidths were estimated using combined LPC and spectrographic analyses. Source functions were synthesized by least-squares fitting a simplified LF model [Y. Qi and N. Bi, J. Acoust. Soc. Am. 96, 1182–1185 (1994)] to the glottal flow derivative. Three versions of each voice were created. The first was constructed by extracting one cycle from the original voice and repeating it to form a 1-s signal. The second was constructed by recombining the inverse filtered source and estimated vocal tract resonances. The third version comprised the LF-modeled source combined with the estimated vocal tract resonances. Expert listeners compared the three versions of each voice, and results were interpreted in terms of the specific differences among stimuli. This procedure allowed evaluation of the extent and perceptual importance of information lost first by inverse filtering and then by fitting the LF model to the resulting volume velocity signal. [Research supported by NIH.]

A pressure-regulated model of normal and pathologic phonation.

Recent evidence suggests that the lung-thorax system functions as a constant pressure source during phonation. However, previous animal models used a constant flow source. This article describes an in vivo canine model that maintains a constant subglottic pressure during phonation to more closely simulate the pulmonary system. At any given subglottic pressure, increasing levels of recurrent laryngeal nerve stimulation resulted in a significant rise in resistance followed by a plateau. Increasing levels of superior laryngeal nerve stimulation, however, produced no significant change in glottal resistance. Three experimental conditions were studied: normal, unilateral recurrent laryngeal nerve paralysis, and paralysis followed by arytenoid adduction. In normal canines, maximal vocal efficiency values were the highest, indicating the best match between pressure and resistance. The vocal efficiency values were significantly lower in recurrent laryngeal nerve paralysis, indicating pressure-resistance mis-match. Arytenoid adduction increased the maximal vocal efficiency values and decreased the mismatch observed in the paralyzed state. These findings may provide insight into an understanding of normal and pathologic laryngeal behavior.

A pressure-regulated model of normal and pathologic phonation

A pressure-regulated model of normal and pathologic phonation