Jody Kreiman

University of California, Los Angeles, Dept. of Head and Neck Surgery, Faculty Member

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Address: Department of Head and Neck Surgery
UCLA School of Medicine
31-24 Rehab Center
1000 Veteran Avenue
Los Angeles, CA 90095-1794

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Papers by Jody Kreiman

Effects of driving pressure and recurrent laryngeal nerve stimulation on glottic vibration in an <i>in vivo</i> constant pressure model of phonation

Journal of the Acoustical Society of America, Apr 1, 1996

Otolaryngology-Head and Neck Surgery Volume 113 Number2 Scientific Sessions-Tuesday P 127 cosal w... more Otolaryngology-Head and Neck Surgery Volume 113 Number2 Scientific Sessions-Tuesday P 127 cosal wave started from the MU and propagated upward. The vocal fold became longer during phonation at a higher pitch than a comfortable pitch. The subglottic vault, surrounded by the bilateral MUs, was narrower during phonafion at a higher pitch. The MU appeared less marked during phonation at a higher pitch than that seen at a comfortable pitch. An upward shift of the MU toward the oral side at a higher pitch was not confirmed in living humans.

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A physiologically and perceptually motivated voice source model

Journal of the Acoustical Society of America, May 1, 2013

Many glottal source models have been proposed, but none has been systematically validated percept... more Many glottal source models have been proposed, but none has been systematically validated perceptually. Our previous work showed that model fitting of the negative peak of the flow derivative is the most important predictor of perceptual similarity to the target voice. In this study, a new voice source model motivated by high-speed laryngeal videoendoscopy is proposed to capture perceptually-important source shape aspects. Six voice source models (the proposed model, two previous models developed at UCLA, as well as the Fujisaki-Ljungkvist, Liljencrants-Fant, and Rosenberg models) were fitted to 40 natural voices obtained by inverse filtering and analysis-by-synthesis (AbS). We generated synthetic copies of the voices using each modeled source pulse, with all other parameters held constant, and then conducted a visual sort-and-rate task in which listeners assessed the extent of perceived match between the original natural voice samples and each copy. Model fitting results showed that the proposed model provides a more accurate fitting to the AbS-derived source than the other models. Perceptual experiments showed that the proposed model provides a close match to the original natural voice. Perceptual studies examining the extent to which each model matches the target tokens will also be reported. [Work supported by NSF grant IIS-1018863 and NIH/NIDCD grant DC01797.]

Synchronizing videostroboscopic images of human laryngeal vibration with physiological signals

American Journal of Otolaryngology, 1992

This report describes a new system that permits the precise correlation of videostroboscopic imag... more This report describes a new system that permits the precise correlation of videostroboscopic images with corresponding physiological measures, such as glottography and subglottic pressure. Method: A healthy volunteer had unilateral vocal cord paralysis induced by infiltrating local anesthesia into the recurrent and superior laryngeal nerve. Vocal-fold vibrations were monitored by photoglottography (PGG) and electroglottography (EGG). Analog signals from the EGG and PGG were synchronized with the video and correlated. Results: The method described permits images to be sampled throughout sustained phonation. This technique allows study of events during glottic vibration. Results obtained have been in close agreement with previous studies that correlate the vocal-fold morphology to glottographic signal using other methods. This technique is inexpensive in comparison with high-speed filming. The main disadvantage of this method is related to the limitations of stroboscopy. Copyright 0 1992 by W.B. Saunders Company Videostroboscopy has gained widespread acceptance for use in the assessment of laryngeal vibration, and can complement glottographic and aerodynamic measures in the objective analysis of voice. During stroboscopy, light flashes are generated in synchrony with the fundamental frequency of laryngeal vibration. These flashes of light are slightly out of phase with the fundamental frequency, creating a montage of individual images from numerous consecutive glottal cycles. This montage stimulates a moving image of the vibrating vocal folds.* The correlation of videostroboscopic images of the vibrating vocal folds with specific points on physiological waveforms would improve our understanding of this data. In the past, this type of comparison could be made only at a small number of research centers

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The relationship between open quotient and H1*-H2*

Journal of the Acoustical Society of America, Oct 1, 2008

It is widely assumed that changes in open quotient (OQ) produce corresponding changes in H1*-H2*,... more It is widely assumed that changes in open quotient (OQ) produce corresponding changes in H1*-H2*, but empirical data supporting this relationship are scant. To provide such data, high-speed video images and audio signals were simultaneously recorded from six speakers producing the vowel /i/ while varying F0 from high to low and voice quality from pressed to breathy. Across speakers, the observed relationship between OQ and H1*-H2* was much weaker than generally assumed. Patterns of covariation also differed substantially from speaker to speaker. Estimation of harmonic amplitudes was complicated by difficulties in determining the frequency of F1 when F0 was high and by uncertainties regarding the F1 bandwidth in the presence of a persistent glottal chink. Use of analysis-by-synthesis allowed correction of formant values, but bandwidth estimation remains problematic and will be discussed further at the conference. [Work supported by NIH Grant DC01797 and NSF Grant BCS-0720304.]

UCLA High-Speed Laryngeal Video and Audio

Perceptual evaluation of voice source models

The Journal of the Acoustical Society of America, 2015

Models of the voice source differ in their fits to natural voices, but it is unclear which differ... more Models of the voice source differ in their fits to natural voices, but it is unclear which differences in fit are perceptually salient. This study examined the relationship between the fit of five voice source models to 40 natural voices, and the degree of perceptual match among stimuli synthesized with each of the modeled sources. Listeners completed a visual sort-and-rate task to compare versions of each voice created with the different source models, and the results were analyzed using multidimensional scaling. Neither fits to pulse shapes nor fits to landmark points on the pulses predicted observed differences in quality. Further, the source models fit the opening phase of the glottal pulses better than they fit the closing phase, but at the same time similarity in quality was better predicted by the timing and amplitude of the negative peak of the flow derivative (part of the closing phase) than by the timing and/or amplitude of peak glottal opening. Results indicate that simpl...

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Modeling measured glottal volume velocity waveforms

The Annals of otology, rhinology, and laryngology, 2003

The source-filter theory of speech production describes a glottal energy source (volume velocity ... more The source-filter theory of speech production describes a glottal energy source (volume velocity waveform) that is filtered by the vocal tract and radiates from the mouth as phonation. The characteristics of the volume velocity waveform, the source that drives phonation, have been estimated, but never directly measured at the glottis. To accomplish this measurement, constant temperature anemometer probes were used in an in vivo canine constant pressure model of phonation. A 3-probe array was positioned supraglottically, and an endoscopic camera was positioned subglottically. Simultaneous recordings of airflow velocity (using anemometry) and glottal area (using stroboscopy) were made in 3 animals. Glottal airflow velocities and areas were combined to produce direct measurements of glottal volume velocity waveforms. The anterior and middle parts of the glottis contributed significantly to the volume velocity waveform, with less contribution from the posterior part of the glottis. The ...

Perceptual importance of time-domain features of the voice source

The Journal of the Acoustical Society of America, 2014

Our previous study examined the perceptual adequacy of different source models. We found that per... more Our previous study examined the perceptual adequacy of different source models. We found that perceived similarity between modeled and natural voice samples was best predicted (in the time dimension) by thematch between waveforms at the negative peak of the flow derivative (R2 = 0.34). The extent of fit during the opening phase of the source pulses added only 2% to perceived match. However, in that study model, fitting was unweighted, and results might differ if another approach were used. In this study, we constrained the models to fit the negative peak of the flow derivative precisely. We fit 6 different source models to 40 natural voice sources, and then generated synthetic copies of the voices using each modeled source pulse, with all other synthesizer parameters held constant. We then conducted a visual sort-and-rate task in which listeners assessed the extent of perceived match between the original natural voice samples and each copy. Discussion will focus on the specific stre...

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WPP, No. 110: Perception of spectral slopes and tone identification in White Hmong

This study investigates the importance of source spectrum slopes in the perception of phonation b... more This study investigates the importance of source spectrum slopes in the perception of phonation by White Hmong listeners. In White Hmong, non-modal phonation (breathy or creaky voice) accompanies certain lexical tones, but its importance in tonal contrasts is unclear. In this study, native listeners participated in two perception tasks, in which they were asked to identify the word they heard. In the first task, participants heard natural stimuli with manipulated F0 and duration (phonation unchanged). Results indicate that phonation is important in identifying the breathy tone, but not the creaky tone. Thus, breathiness can be viewed as contrastive in White Hmong. Next, to understand which parts of the source spectrum listeners use to perceive contrastive breathy phonation, source spectrum slopes were manipulated in the second task to create stimuli ranging from modal to breathy sounding, with F0 held constant. Results indicate that changes in H1-H2 (difference in amplitude between the first and second harmonics) and H2-H4 (difference in amplitude between the second and fourth harmonics) are independently important for distinguishing breathy from modal phonation, consistent with the view that the percept of breathiness is influenced by a steep drop in harmonic energy in the lower frequencies. * We would like to thank Susan Yang and members of the Hmong-American Partnership in St. Paul, MN, for their assistance in recruiting and testing participants. We would also like to thank Norma Antoñanzas-Barroso for her help with the UCLA voice synthesizer.

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Characteristics of an In Vivo Canine Model of Phonation With a Constant Air Pressure Source

The Laryngoscope, 1996

Many previous studies of laryngeal biomechanics using in vivo models have employed a constant air... more Many previous studies of laryngeal biomechanics using in vivo models have employed a constant air flow source. Several authors have recently suggested that the lung‐thorax system functions as a constant pressure source during phonation. This study describes an in vivo canine system designed to maintain a constant peak subglottic pressure (Psub) using a pressure‐controlling mechanism.Increasing levels of recurrent laryngeal nerve (RLN) stimulation resulted in a significant rise in resistance followed by a plateau. For a given Psub, flow decreased significantly and precipitously with increasing stimulation and then quickly plateaued. Vocal intensity increased with increasing RLN stimulation until a peak was reached. After this peak, intensity dropped until a plateau was reached, corresponding to the flow minimum. At a given Psub, increasing levels of RLN stimulation resulted in a normal distribution of vocal efficiencies.

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Analysis by synthesis of pathological voices using the Klatt synthesizer

Speech Communication, 1997

The ability to synthesize pathological voices may provide a tool for the development of a standar... more The ability to synthesize pathological voices may provide a tool for the development of a standard protocol for assessment of vocal quality. An analysis-by-synthesis approach using the Klatt formant synthesizer was applied to study 24 tokens of the vowel rar spoken by males and females with moderate-to-severe voice disorders. Both temporal and spectral features of the natural waveforms were analyzed and the results were used to guide synthesis. Perceptual evaluation indicated that about half the synthetic voices matched the natural waveforms they modeled in quality. The stimuli that received poor ratings reflected failures to model very unsteady or ''gargled'' voices or failures in synthesizing perfect copies of the natural spectra. Several modifications to the Klatt synthesizer may improve synthesis of pathological voices. These modifications include providing jitter and shimmer parameters; updating synthesis parameters as a function of period, rather than absolute time; modeling diplophonia with independent parameters for fundamental frequency and amplitude variations; providing a parameter to increase low-frequency energy; and adding more pole-zero pairs. q 1997 Elsevier Science B.V. Resumé Pouvoir synthetiser des voix pathologiques peut etre un outil utile pour le developpement de protocoles standards pouŕˆĺ 'evaluation de la qualite vocale. On a applique une methode d'analyse-synthese, utilisant le synthetiseur de Klatt, a 24´´´`´è nonces de la voyelle rar prononces par des locuteurs hommes et femmes ayant des troubles de la parole allant de modere á´´´´s evere. Les indices tant spectraux que temporels des formes d'onde naturelles ont ete analyses et les resultats utilises pouŕ`´´´´ǵ uider la synthese. Une evaluation perceptive montre qu'environ la moitie des voix synthetiques sont considerees commè´´´´í dentiques en qualite aux voix naturelles qu'elles sont sensees modeliser. Les stimuli consideres comme differents refletent´´´´l es echecs de la modelisation de voix tres instables ou ''gargarisees'' ou d'imperfection dans la reproduction des spectreś´`ń aturels. Diverses modifications apportees au synthetiseur de Klatt pourraient ameliorer la synthese des voix pathologiques.´´C es modifications concernent l'introduction de parametres de jitter et de shimmer; la mise a jour des parametres de synthesè``è n fonction de la periode plutot qu'en fonction d'une duree absolue; la modelisation de la diplophonie par des parametreśˆ´´)

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Effects of driving pressure and recurrent laryngeal nerve stimulation on glottic vibration in an in vivo constant pressure model of phonation

The Journal of the Acoustical Society of America, 1996

Most in vivo studies of phonation have used constant flow models. However, because the lung–thora... more Most in vivo studies of phonation have used constant flow models. However, because the lung–thorax system is better viewed as a constant pressure source, a constant pressure in vivo canine model was developed. In this model, driving pressure and recurrent laryngeal nerve (RLN) stimulation are independent variables, and subglottic pressure (Psub; measured immediately under the glottis), air flow, fundamental frequency (F0), and glottic area are dependent variables. In three dogs, Psub and air flow were measured with constant RLN stimulation and varying driving pressure, and in another condition with constant driving pressure and varying RLN stimulation. Videostroboscopic measures on four animals assessed glottic areas with constant RLN stimulation and varying driving pressure. With constant RLN stimulation, increasing driving pressure had no effect on glottic area, while F0, and air flow increased significantly. Changes in Psub were small in comparison to changes in driving pressure....

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Laryngeal resistance of an in vivo canine model of phonation with a constant air pressure source

The Journal of the Acoustical Society of America, 1993

Previous studies of laryngeal biomechanics using in vivo models have generally used a constant ai... more Previous studies of laryngeal biomechanics using in vivo models have generally used a constant air flow source. Several authors have recently suggested that during phonation, the lung–thorax system functions as a constant pressure source. The present paper describes an in vivo canine system designed to maintain a constant peak subglottic pressure (Psub) using a pressure-controlling mechanism. It was found that with a decrease in Psub, the range of recurrent laryngeal nerve stimulation (RLNS) voltage needed to induce phonation was reduced. At a given superior laryngeal nerve stimulation (SLNS) level and Psub, increasing levels of RLNS resulted in a normal distribution of vocal efficiencies. For each SLNS and Psub, minimum and maximum levels of RLNS were determined outside of which no phonation was possible. Levels of RLNS that produced an optimal stable phonation were also identified. Increasing levels of RLNS resulted in significant decreases in glottal air flow. Contrary to a previ...

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Perceptual evaluation of voicing source models

The Journal of the Acoustical Society of America, 2012

Many models of the glottal source have been proposed, but none has been systematically validated ... more Many models of the glottal source have been proposed, but none has been systematically validated perceptually, so that it is unclear whether deviations from perfect fit have perceptual importance. If model fit fails in ways that have no perceptual significance, such “errors” can be ignored, but poor fit with respect to perceptually-important features has both theoretical and practical importance. To address this issue, we fit 6 different source models to 40 natural voice sources, and then evaluated fit with respect to time-domain landmarks on the source waveforms and details of the harmonic voice source spectrum. We also generated synthetic copies of the voices using each modeled source pulse, with all other synthesizer parameters held constant, and then conducted a visual sort-and-rate task in which listeners assessed the extent of perceived match between the original natural voice samples and each copy. Discussion will focus on the specific strengths and weaknesses of each modelin...

A physiologically and perceptually motivated voice source model

The Journal of the Acoustical Society of America, 2013

The relationship between open quotient and H1*-H2*

The Journal of the Acoustical Society of America, 2008

LF source model adequacy for pathological voices

The Journal of the Acoustical Society of America, 1997

The adequacy with which source models describe pathological phonation has been little studied, an... more 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...

Perceptually motivated modeling of noise in pathological voices

The Journal of the Acoustical Society of America, 1998

Research investigating the correlation of acoustic measures of noise and the perception of pathol... more Research investigating the correlation of acoustic measures of noise and the perception of pathological voice quality has consistently demonstrated a moderate association. However, this correlational approach cannot address basic questions concerning their cause and effect relationship, such as how carefully noise must be modeled to preserve the perceived pathological vocal quality, and what particular aspects of the noise are necessary to preserve natural vocal quality. To address these questions, an analysis by synthesis approach was applied to a large sample of natural pathological vowels varying in severity of pathology. Several synthetic versions of each voice were created using an LF source model and a formant synthesizer. Amplitude and spectral characteristics of the noise were varied as necessary. Stimuli were compared perceptually to the original voice and to each other. A discussion will focus on the procedures necessary to adequately model noise in voices with severe voca...

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Development of a glottal area index that integrates glottal gap size and open quotient

The Journal of the Acoustical Society of America, 2013

Because voice signals result from vocal fold vibration, perceptually meaningful vibratory measure... more Because voice signals result from vocal fold vibration, perceptually meaningful vibratory measures should quantify those aspects of vibration that correspond to differences in voice quality. In this study, glottal area waveforms were extracted from high-speed videoendoscopy of the vocal folds. Principal component analysis was applied to these waveforms to investigate the factors that vary with voice quality. Results showed that the first principal component derived from tokens without glottal gaps was significantly (p < 0.01) associated with the open quotient (OQ). The alternating-current (AC) measure had a significant effect (p < 0.01) on the first principal component among tokens exhibiting glottal gaps. A measure AC/OQ, defined as the ratio of AC to OQ, was proposed to combine both amplitude and temporal characteristics of the glottal area waveform for both complete and incomplete glottal closures. Analyses of “glide” phonations in which quality varied continuously from bre...

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On parameterizing glottal area waveforms from high-speed images

The Journal of the Acoustical Society of America, 2012

Because voice signals result from vocal fold vibration, perceptually-meaningful vibratory measure... more Because voice signals result from vocal fold vibration, perceptually-meaningful vibratory measures should quantify those aspects of vibration that correspond to differences in voice quality. In this study, glottal area waveforms were calculated from high-speed images of the vocal folds. Principal component analysis was applied to these waveforms to investigate the factors that vary with voice quality. Results showed that the first two principal components were significantly (p < 0.01) associated with the open quotient and the ratio of alternating-current to direct-current components. However, these conventional source measures, which are based on glottal flow, do not fully characterize observed variations in glottal area pulse shape across different glottal configurations, especially with respect to patterns of glottal closure that may be perceptually important. A source measure, the Source Dynamic Index (SDI), is proposed to characterize glottal area waveform variation for both ...

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