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Objective measurement of vocal function is important in evaluating phonatory disorders, planning treatment, and documenting the effects of therapy. Glottographic measurement, ie, measures that describe glottal movement, can be performed and analyzed relatively easily, and can be related to the pathophysiology of vocal dysfunction. In our clinic, simultaneous recording of acoustic, photoglottographic and electroglottographic signals is being used in the evaluation of patients with voice disorders associated with neurologic impairments. Our experience with these measures indicates that they may provide detailed information about the vibratory patterns of the vocal folds, which appears to differentiate some phonatory characteristics among patients with differing types of disorders.

INTRODUCTION Persons with a hoarse voice are frequently referred to as having a "voice problem." While this is true in the broadest sense, it is obviously not enough to describe any particular vocal disability. It means about as much as if an eye specialist were to say that he is treating patients with "seeing problems," or if an audiologist were to write about the "hearing problems" seen in his hearing clinic without giving any of the elaborate and detailed findings commonly encountered in audiologic publications. The great progress of medical science in this century is partly due to the rapidly advancing methods of analysis and description of physiologic functions. The same is true with regard to vocal function, and the medical specialty of voice therapy or phoniatrics has successfully kept pace during the first century of its existence with the progress of other medical sciences. Incidentally, the name of the

A 31 years old male who had post traumatic stenosis of the trachea associated with laryngeal nerve paralysis was treated by end-to-end anastomosis of the trachea In this procedure the thyro-hyoid muscles and pharyngoconstrictos were cut and the lower part of the trachea was free from the superior mediastinum before the stenotic portion of the trachea was removed and end-to-end anastomosis of the trachea was performed.Post-operatively no swallowing difficulty was observed even under cineradiography, and the air way was still patent 2 years and 6 months after the surgery.Aphonia was present in the early postoperative stage, but vocal function improved gradually and considerably, and at present, we can observe a good motility of the false vocal cords and the left vocal cord.Improvement of phonetic function has been proved on cineradiogram, radiogram and electromyogram, and according to the results of these observations, the author considered the regeneration of the recurrent nerve.

The part played by the supraglottic area, the so-called laryngeal aditus, in voice and phonopathic conditions has long been known to be considerable. This had been pointed out long before the fundamental concepts of vocal function were upset by Cotton, 1 in 1940, when he verified experimentally the postulates of Husson and Tarneaud. 2 In 1902 Scripture 3 suggested that the false vocal cords might well have a definite function. Such a function in the production of voice was defined in 1915 by Muckey. 4 He formulated a law, which has since proved to be true, namely, that correct voice production may be summed up as noninterference with (1) the action of the vocal cords and (2) the opening of the tube that leads out through the pharynx, the buccal cavity and the lips. Muckey went on to say that as a strong fundamental tone is important in the production

The purpose of this investigation was to explore the interrelationship of various measures related to vocal function, speech rate, and laryngeal appearance in elderly women. Speakers were 20 women ranging in age from 67 to 86 years. An indirect laryngoscopic examination that included judgments on glottal closure and vocal fold appearance was performed on each speaker. Eight measures related to vocal performance (the production capabilities of the mechanism with regard to pitch range, intensity range, and phonation time) were collected on each speaker. Further, acoustic measures of intensity and fundamental frequency stability were made from sustained vowels, and a reading passage was analyzed for reading rate and intensity level. Factor analysis procedures revealed an association of maximum phonation time with measures of vocal intensity, as well as with pitch range measures. Surprisingly, reading rate was grouped with measures of F o stability as well as with maximum vocal intensity. Although laryngoscopic findings are in general agreement with those reported previously in elderly women (Honjo & Isshiki, 1980), inadequate glottal closure was observed more frequently, and vocal cord edema less frequently, in these women.

Radiation therapy for early laryngeal cancer offers an excellent probability of cure as well as preservation of vocal function. Reported failure rates range from 9 to 21% in patients with T1 lesions, and from 28 to 44% in those with T2 lesions, the majority of whom are subsequently salvaged by surgery. Results obtained at the Radiotherapy Center of the University of Wisconsin Hospitals in 44 patients during the period from 1960 to 1972 yielded failure rates of 21% in patients with T1 tumors and 38% in patients with T2 tumors at 5 years. Five of the eight recurrences were salvaged with surgery yielding an overall tumor control rate of 93%. The larynx was preserved in 82% of the cases. Determinate 5-year survival was 91% in T1 cases and 86% in T2 cases. Failure rates at 3 years were 18% for T1 tumors and 30% for T2 lesions. These results are in conflict with those reported by Brandenburg and Rutter as being 46% and 60% respectively. Ultimate success in the treatment of laryngeal cancer rests in the full cooperation between surgeons and radiotherapists.

Publisher Summary Several methods—laryngoscopy, stroboscopy, thermography, electromyography, pneumotachography, glottography, and acoustic analysis—have been used in laryngeal research and diagnosis. However, for routine clinical evaluation of laryngeal function, acoustic analysis has an advantage over the other methods because of its non-intrusive nature and its potential for providing quantitative data with reasonable expenditures of analysis time. This chapter discusses the methods for the acoustic analysis of voices that are affected by laryngeal pathology and procedures for determining acoustic parameters applicable to screening and to clinical assessment. These methods use digital computer techniques for voice analysis to extract acoustic measures of vocal function from the speech signal. The vocal fold movement is related to the acoustic output on which the acoustic methods are based, and the theoretical bases and results of several methods are compared, indicating the problems that require additional research.

Assessment of vocal function is essential in deciding the type of surgery that is indicated, intraoperatively which procedure should be taken in response to the vocal change, and postoperatively the effect of surgery on the voice. The description of the examinations here is confined only to those that are practical and normally required for surgery. For details, the reader is referred to works such as by Hirano (19810, Wendler and Seidner (19871), and Baken (19871). Voice recording is made on audio or videotape together with a laryngeal video-picture for later analysis, comparison, and discussion. The information is essential in determining the underlying mechanism for a given hoarse voice, especially whether any rheological change of the vocal cords, e.g., increased stiffness, is involved or not.

This study examined the feasibility of clinically adapting lightweight, compact spirometers to perform aerodynamic assessment of vocal function in adults. The validity of vital capacity and phonation quotient measurements made with such instruments was assessed, and a multiple regression analysis was performed in order to develop a formula for estimating mean flow rate from the phonation quotient. Nineteen healthy young adults performed the aerodynamic tasks. Data provided by a Collins wet respirometer were compared with data provided by three handheld, lightweight spirometers. Vital capacity and maximum phonation time were the key elements used to predict mean flow rate. Findings indicated that handheld spirometers can be used to provide aerodynamic assessment of vocal function.

Studies concerning the effectiveness of voice therapy are lacking. There is little experimental verification that therapy techniques actually achieve specific change in abusive vocal function. Guidelines are presented regarding conceptual and methodological consideration for future investigations. Divergent terminology, philosophy, and issues of voice therapy are presented to serve as an overview and as a basis for research direction. Suggestions are offered for selecting experimental designs.

Blunt trauma can cause a wide range of injuries to the cartilaginous framework of the larynx. The severity of injury that is required to cause a permanent disorder of vocal function if left untreated has not been defined. A study using excised canine and human larynges was undertaken to identify the effects of minimal displacement or malalignment in simulated thyroid cartilage fractures on selected voice production measurements. These fractures were found to cause changes in glottal configuration sufficient to affect glottal resistance as well as amplitude and noise content of the voice signal produced by each larynx. Therefore, relatively minor injuries of the thyroid cartilage may cause potentially serious disorders of phonation.

The authors have developed standardized assessment and control techniques designed to provide objective measures of tardive dyskinesia in patients progressing through an experimental treatment program. Standardized videotaping is carried out and blind ratings on the Abnormal Involuntary Movement Scale are made by a team of psychiatrists and neurologists. Other assessments include several measurements of vocal function and a quantitative acceleration profile standardized on normal subjects. Such measures allow quantifiable determination of response to drug treatment and may provide clues to the etiology and definition of the dyskinetic syndrome.

Acoustic measures of vocal function are routinely used for the assessment of disordered voices, and for monitoring patients' progress over the course of therapy. In the paper, speech signals were decomposed using an adaptive time-frequency transform algorithm, and the signal decomposition parameters such as the octave (scale) maximum, octave mean, and frequency ratio were analyzed using a statistical pattern analysis method. A classification accuracy of 93.4% was obtained with a database of 212 speech signals (51 normal and 161 pathological cases).

The waveform of the volume velocity of the airflow through the larynx, as obtained by inverse filtering the volume velocity of the airflow exiting the mouth and nose, is a potential convenient noninvasive measure of the vibratory pattern of the vocal folds during voiced speech. Of special interest is a measure that is sufficiently robust for clinical use in the detection, monitoring, and treatment of voice disorders. The problems in this application are of three types: (1) The parameters of the inverse filter must be set to match the acoustic transfer function of the vocal tract; (2) glottal airflow is, in some way, not an accurate indicator of vocal fold motion; and (3) the analysis must be accurate under a wide range of normal and disordered voice qualities and possible nasal coupling. Because of these problems, it has been difficult to find a robust and accurate automatic procedure, even if the analysis is restricted to only the simplest case of open vowels. However, there appears to be a rather straig...

The degree of closeness of the arytenoid cartilages (laryngeal adduction) plays an important role in vocal function and quality. In this paper, adduction for steady vowels was varied between voiced qualities of breathy (greater abduction) to normal to constricted (greater adduction). The superior view of the larynx of various subjects was videotaped and dimensions of laryngeal adduction were measured. The measurements were compared with values of the abduction quotient [1. R. Titze, J. Acoust. Soc. Am. 75, 570–580 (1984)] obtained from simultaneous recordings of the electroglottograph signal and with a measure of electroglottograph waveform width. The width measure strongly correlates with the abduction quotient. Results suggest that the adduction measures may be useful for clinical and research purposes. [Work supported by NIH.]

In Reply .—In response to the letter by Greene, determination of the vocal quality in the patients reported in our study was graded in a single-blind fashion by three independent, trained, speech and voice therapists. Recordings were made three months or more postoperatively. The grading system was that employed by Koufman 1 in a previous article and noted on page 534 of Otolaryngology—Head & Neck Surgery . With future stroboscopic evaluations, we hope to better delineate the vocal function following endoscopic laser surgery of the vocal cords, and we hope that others will also review their cases in a more critical fashion using more sophisticated measurements of vocal quality. Assuming that the cure rate following endoscopic laser surgery for small carcinomas of the vocal cords is certainly equivalent to that of previously recommended forms of therapy, and that the cost and time of treatment are much less, we believe that improved