Jody Kreiman

Voice discrimination and recognition are separate abilities

Studies of brain-damaged subjects indicate that recognizing a familiar voice and discriminating among unfamiliar voices may be selectively impaired, and thus that the two are separate functions. Familiar voice recognition was impaired in cases of damage to the right (but not the left) hemisphere, while impaired unfamiliar voice discrimination was observed in cases with damage to either hemisphere.

Measuring vocal quality with speech synthesis

Much previous research has demonstrated that listeners do not agree well when using traditional rating scales to measure pathological voice quality. Although these findings may indicate that listeners are inherently unable to agree in their perception of such complex auditory stimuli, another explanation implicates the particular measurement method-rating scale judgments-as the culprit. An alternative method of assessing quality-listener-mediated analysis-synthesis-was devised to assess this possibility. In this new approach, listeners explicitly compare synthetic and natural voice samples, and adjust speech synthesizer parameters to create auditory matches to voice stimuli. This method is designed to replace unstable internal standards for qualities like breathiness and roughness with externally presented stimuli, to overcome major hypothetical sources of disagreement in rating scale judgments. In a preliminary test of the reliability of this method, listeners were asked to adjust the signal-to-noise ratio for 12 synthetic pathological voices so that the resulting stimuli matched the natural target voices as well as possible For comparison to the synthesis judgments, listeners also judged the noisiness of the natural stimuli in a separate task using a traditional visual-analog rating scale. For 9 of the 12 voices, agreement among listeners was significantly (and substantially) greater for the synthesis task than for the rating scale task. Response variances for the two tasks did not differ for the remaining three voices. However, a second experiment showed that the synthesis settings that listeners selected for these three voices were within a difference limen, and therefore observed differences were perceptually insignificant. These results indicate that listeners can in fact agree in their perceptual assessments of voice quality, and that analysis-synthesis can measure perception reliably.

The perceptual structure of pathologic voice quality

Although perceptual assessment is included in most protocols for evaluating pathologic voices, a standard set of valid scales for measuring voice quality has never been established. Standardization is important for theory and for clinical acceptance, and also because validation of objective measures of voice depends on valid perceptual measures. The present study used large sets (n = 80) of male and female voices, representing a broad range of diagnoses and vocal severities. Eight experts judged the dissimilarity of each pair of voices, and responses were analyzed using nonmetric individual differences multidimensional scaling. Results indicate that differences between listeners in perceptual strategy are so great that the fundamental assumption of a common perceptual space must be questioned. Because standardization depends on the assumption that listeners are similar, it is concluded that efforts to standardize perceptual labels for voice quality are unlikely to succeed. However, analysis by synthesis may provide an alternate means of modeling quality as a function of both voices and listeners, thus avoiding this problem.

Measurement of Young's Modulus in the in Vivo Human Vocal Folds:

Currently, surgeons have no objective means to evaluate and optimize results of phonosurgery intraoperatively. Instead, they usually judge the vocal folds subjectively by visual inspection or by listening to the voice. This paper describes a new device that measures Youngs (elastic) modulus values for the human vocal fold intraoperatively. Physiologically, the modulus of the vocal fold may be important in determining the nature of vocal fold vibration in normal and pathologic states. This study also reports the effect of recurrent laryngeal nerve stimulation on Youngs modulus of the human vocal folds, measured by means of transcutaneous nerve stimulation techniques. Youngs modulus increased with increases in current stimulation to the recurrent laryngeal nerve. Ultimately, Youngs modulus values may assist surgeons in optimizing the results of various phonosurgeries.

Treatment of Parkinson Hypophonia With Percutaneous Collagen Augmentation

Objectives: It has been estimated that more than 70% of patients with Parkinson disease experience voice and speech disorders characterized by weak and breathy phonation, and dysarthria. This study reports on the efficacy of treating Parkinson patients who have glottal insufficiency.

Recognition of emotional‐prosodic meanings in speech by autistic, schizophrenic, and normal children

The abilities of autistic, schizophrenic, and normal‐control children to label four emotional intonations (the emotional task) in speech were tested, along with a linguistic task. All stimuli were pretested on normal adults. Older (≥ 8 years of age) normal children performed as well as adults on both tasks; younger normal children and both younger and older autistic children performed poorly on the emotional task; children (all older) diagnosed as schizophrenic were not significantly impaired in either task. Mental age was not correlated with performance in autistic children. The relevance of these results to other findings regarding emotional and linguistic behaviors in normal and disabled children is considered.

Function of the interarytenoid muscle in a canine laryngeal model

Fundamental frequency is controlled by contraction of the thyroarytenoid (TA) and cricothyroid (CT) muscles. While activity of the CT muscle is known to tense and thin the vocal folds, little is known about the effect of the TA muscle on vocal fold vibration. An in vivo canine laryngeal model was used to examine the role of the TA muscle in controlling phonation. Isolated TA muscle activation was obtained by stimulating sectioned terminal TA branches through small thyroid cartilage windows. Subglottic pressure measures, electroglottographic and photoglottographic signals, and acoustic signals were obtained in 5 mongrel dogs during dynamic and static variations in TA muscle activity. Results indicated that TA muscle activation is a major determinant in sudden shifts from high-frequency to modal phonation. Subglottic pressure increased and open quotient decreased gradually with increasing TA activation.

Combined Arytenoid Adduction and Laryngeal Reinnervation in the Treatment of Vocal Fold Paralysis

Objective/Hypothesis: Glottal closure and symmetrical thyroarytenoid stiffness are two important functional characteristics of normal phonatory posture. In the treatment of unilateral vocal cord paralysis, vocal fold medialization improves closure, facilitating entrainment of both vocal folds for improved phonation, and reinnervation is purported to maintain vocal fold bulk and stiffness. A combination of medialization and reinnervation would be expected to further improve vocal quality over medialization alone.

In the Beginning Was the Familiar Voice: Personally Familiar Voices in the Evolutionary and Contemporary Biology of Communication

The human voice is described in dialogic linguistics as an embodiment of self in a social context, contributing to expression, perception and mutual exchange of self, consciousness, inner life, and personhood. While these approaches are subjective and arise from phenomenological perspectives, scientific facts about personal vocal identity, and its role in biological development, support these views. It is our purpose to review studies of the biology of personal vocal identity—the familiar voice pattern—as providing an empirical foundation for the view that the human voice is an embodiment of self in the social context. Recent developments in the biology and evolution of communication are concordant with these notions, revealing that familiar voice recognition (also known as vocal identity recognition or individual vocal recognition) has contributed to survival in the earliest vocalizing species. Contemporary ethology documents the crucial role of familiar voices across animal species in signaling and perceiving internal states and personal identities. Neuropsychological studies of voice reveal multimodal cerebral associations arising across brain structures involved in memory, emotion, attention, and arousal in vocal perception and production, such that the voice represents the whole person. Although its roots are in evolutionary biology, human competence for processing layered social and personal meanings in the voice, as well as personal identity in a large repertory of familiar voice patterns, has achieved an immense sophistication.

Analysis by synthesis of pathological voices using the Klatt synthesizer

Abstract 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 /a/ 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.