Wilbur J. Gould

Computer Analysis of Hoarseness

The harmonic components in hoarse voice were separated from the noise components by using a small laboratory computer. The ratio of harmonics to noise or S/N ratio, was calculated and compared with the auditory impression for 58 subjects. The calculated results showed a definite correlation to the auditory impression, and it is suggested that this would be a useful method for the quantitative evaluation of hoarseness.

Vocal shimmer in sustained phonation of normal and pathologic voice.

Vocal shimmer during sustained phonation was measured in normal subjects and patients with laryngeal polyps, using the mean amplitude difference between consecutive cycles expressed in dB. A small laboratory computer was then used for measuring each discrete amplitude and for data processing. The results showed some overlap between the values for two groups studied, but nevertheless it appears that the measured value may be a useful index in screening for laryngeal disorders and for definitive diagnosis of such disorders.

Preliminary evaluation of selected acoustic and glottographic measures for clinical phonatory function analysis

Summary Acoustic and glottographic measures may provide important information that could enhance clinical management and documentation of vocal dysfunction. Acoustic measures such as jitter and shimmer reflect “short-term” perturbations, or instabilities of the voice, and the coefficients of variation for frequency and for amplitude reflect “long-term” perturbations. Interpretations of these acoustic measures are based on the assumption that vocal perturbations may be related to laryngeal tissue abnormalities, asymmetries in vocal fold movement, or neuromuscular fluctuations in the respiratory, laryngeal, or vocal tract systems. The abduction quotient is a glottographic measure related to laryngeal adduction and is obtained from an analysis of the electroglottograph signal. The adduction measure appears to be independent of the acoustic perturbation measures. Interpretations of the acoustic and adductory measures may, therefore, complement each other for greater understanding of a patients laryngeal behavior. Visual displays of the acoustic and glottographic signals also are discussed to demonstrate their value in voice signal interpretations. Case studies illustrate potential interpretations of the acoustic perturbation and abduction quotient measures.

Frequency and amplitude perturbation analysis of electroglottograph during sustained phonation

Electroglottography (EGG) was used to monitor vocal fold vibration patterns in normal subjects and patients with various laryngeal disorders. In order to evaluate the regularity of vocal fold vibration, frequency and amplitude perturbation of EGG waves during sustained phonation were measured with a laboratory computer. The data were compared to the degree of hoarseness evaluated by auditory perception and by sound spectrographic analysis. Frequency and amplitude perturbation measures showed some overlap between normal and pathological groups. However, there was a close relation between perturbation analysis of EGG waves and degree of hoarseness (Spearmans rank correlation coefficient rs = 0.73, p less than 0.0005). Amplitude perturbation was found to be a more sensitive measure of the irregularity of vocal fold vibration than frequency perturbation.

Static Lung Volumes in Singers

It has long been assumed that the superior vocal ability of the trained professional singer arose from a higher than average breathing capacity and consequent above-normal ventilatory efficiency. However, until now, it has not been clear whether this presumed superior pulmonary capacity and breathing efficiency arose from training, from heredity, or from other factors. To clarify the role of training (and by inference that of other factors also) upon the capacity for singing, various indices reflecting static lung volumes, as distinguished from dynamic parameters measured during the act of singing, in trained professional singers, students of voice and subjects with no vocal training, were compared. Results indicated that contrary to reports by others, there were no significant differences in the total lung capacity (TLC) of the trained professional singer and that of the other two groups when allowances were made for age and sex; but when the ability to mobilize or utilize TLC was compared, it was found that the trained singer was much better able to do this than either of the other two groups. Specifically, it was found that the ratio of the residual lung volume (RV) (the amount of air remaining in the lungs at the end of a total voluntary expiration) to TLC was lower in the trained singer than in the students of voice, and that these students, in turn, had a lower RV/TLC ratio than the untrained subjects. These findings, therefore, suggest that the increased singing ability of the trained professional singer arises in large part from the ability to increase breathing efficiency by reducing the residual lung volume and, further, that this ability tends to improve with length of vocal training.

Agenesis of the lung with vascular compression of thetracheobronchial tree

Summary A case of agenesis of one lung withrespiratory difficulty and death caused by vascular compression of the airway is reported. An anomalous course of the pulmonary artery and the position of the aorta were responsible for the tracheal narrowing. Such vascular compression may not be obvious from post-mortem examinations alone since after death the large arteries are no longer full and tense. Anomalous course of great vessels may be of clinical significance in certain cases of agenesis of the lung which have respiratory difficulty.

Vocal efficiency and aerodynamic aspects in voice disorders.

The variation of vocal efficiency for the mean values for normal subjects was investigated in patients with laryngeal disease. The relative contributions of mean flow rate and intrapulmonic pressure to the variation of efficiency were explored to explain aerodynamic aspects in voice disorders. Vocal efficiency was determined by use of expressions involving simultaneous values of sound pressure level, mean flow rate, and intrapulmonic pressure. The intrapulmonic pressure was noninvasively obtained by plethysmographic and pneumotachographic methods. Values of vocal efficiency were generally abnormally low for the types of larynges studied. An aerodynamic-biomechanical classification of laryngeal disease was inferred from the data: 1) large chink of glottis, associated with high flow rate; 2) mass on vocal fold, associated with high values of both flow rate and intrapulmonic pressure; and 3) high stiffness of vocal fold, associated with high values of intrapulmonic pressure.

The clinical voice laboratory. Clinical application of voice research.

In the past decade the number of voice laboratories has increased dramatically. Their primary mission is to enhance patient care by the application of knowledge gained from basic research. They also are dedicated to further improvement of diagnostic and therapeutic resources. The strength of the voice laboratory lies in collaboration between the clinician and the scientist.

Voice analysis of the partially ablated larynx: a preliminary report

This study attempts to obtain a data base of objective information on the phonatory characteristics of the partially ablated larynx. Twenty patients who had previously undergone partial laryngectomy with glottic reconstruction underwent videolaryngoscopy. The visualizations obtained revealed that the mechanism of voice production was due in part to sphincterization and compensatory hypertrophy of glottic and supraglottic remnants. Aerodynamic and phonatory function tests together with acoustical and perceived voice quality analyses of these partially ablated larynges tend to corroborate the videotape impressions in many instances. However, data accumulated thus far only reveal trends that cannot yet be subjected to definitive interpretations. With the incorporation of other methods of evaluation, augmented by the inclusion of more patient material, it is hoped that the information obtained can be used to improve reconstructive techniques, monitor surgical results, and enhance methods of voice rehabilitation in these patients.

Laryngeal phonatory reflex. The effect of anesthetization of the internal branch of the superior laryngeal nerve: Acoustic aspects.

The laryngeal phonatory reflex through the internal branch of the superior laryngeal nerve (SLN) was investigated by means of anesthetization of the nerve, after which acoustic signals were subjected to computer analysis to determine how anesthesia affected basic vocal parameters. Results showed that the anesthetization did not affect the abrupt cycle-to-cycle frequency changes and also did not influence the gross control of the fundamental frequency. But slower fluctuation of the fundamental frequency increased following anesthesia. From these results, it is suggested that the anesthetization of the internal branch of the SLN may derange the fine control mechanism of the larynx without affecting overall or gross performance of the phonatory apparatus.