Laryngeal and phonatory status after burn/inhalation injury: a long term follow-up study.

Although persistent hoarseness has been recognized in patients who have sustained burn and/or smoke inhalation injuries, there is little documentation to support this observation. Furthermore, there is no quantification of either the pervasiveness of the problem or the severity of the dysphonia resulting. It was the intent of this study to examine the laryngeal condition and voice production of a group of patients who were long-term survivors of burns and inhalation injuries. Only 10 patients (8 male and 2 female) of a larger cohort were willing to return for this examination. They were ambulatory and did not require respiratory assistance, and it had been 16 to 25 years since their initial traumas. Videostrobolaryngoscopic examinations were performed and analyzed, measures of various acoustic and aerodynamic parameters were made, and severity of dysphonia was judged. Seven of the 10 subjects were rated by experienced listeners as having some degree of dysphonia. All subjects had some abnormality of the laryngeal mucosa. Stroboscopic examination was found to be helpful in identifying laryngeal abnormalities in at least half of the subjects. Early attention to these problems, many of which are treatable surgically or behaviorally or both could lead to an improved voice for the patient and for this reason an improved quality of life.

Vocal intensity characteristics in normal and elderly speakers.

The relationship of lung pressure, fundamental frequency, peak airflow, open quotient, and maximal flow declination rate to vocal intensity for a normal speaking, young male control group and an elderly male group was investigated. The control group consisted of 17 healthy male subjects with a mean age of 30 years and the elderly group consisted of 11 healthy male subjects with a mean age of 77 years. Data were collected at three levels of vocal intensity: soft, comfortable, and loud, corresponding to 25%, 50%, and 75% of dynamic range, respectively. Phonational threshold pressure and lung pressure were obtained using the intraoral technique. The oral airflow waveform was inverse filtered to provide an approximation to the glottal airflow waveform from which measures of fundamental frequency, peak airflow, open quotient, and maximal flow declination rate were determined. Excess lung pressure was calculated as lung pressure minus estimated phonational threshold pressure. The results show for both groups an increase in sound pressure level across the conditions, with corresponding increases in lung pressure, excess lung pressure, fundamental frequency, peak airflow, and maximal flow declination rate. Open quotient decreased with increasing vocal intensity. Lung pressure, sound pressure level, and peak airflow were all found to be significantly greater for the control group than for the elderly group at each condition. Open quotient was found to be significantly lower in the control group than in the elderly group at each condition. No significant difference was observed for excess lung pressure, phonational threshold pressure, fundamental frequency, or maximal flow declination rate between the two groups. These results show that a difference in vocal intensity does exist between young and elderly voices and that this difference is the result of differences in lung pressure, peak airflow, and open quotient.

Stroboscopic signs associated with benign lesions of the vocal folds.

Stroboscopic signs were systematically rated for a group of 80 patients with benign vocal fold lesions, most of whom had either a nodule or a polyp. Each group revealed a characteristic pattern of ranking of signs and exhibited differences of most predominant signs. The results of the ratings were submitted to a multiple discriminant analysis to determine if post hoc stroboscopic ratings could be used to correctly classify patients into one of four diagnostic groups and into one of two treatment groups. All patients except one were correctly classified into the diagnostic groups, and all were correctly classified into the treatment groups. The important signs for classifying patients into the diagnostic groups were roughness of the edge of the affected vocal fold, phase closure pattern, and phase symmetry. The important signs for classifying patients into the treatment groups were roughness of the edge of the affected vocal fold, glottal closure configuration, and vibration characteristics of the affected (or more affected) vocal fold. The results suggest that objective evaluation of stroboscopic examinations can be valuable in correctly diagnosing patients and in selecting the proper treatment regimen for the patient.

Partial thyroarytenoid myectomy: an animal study investigating a proposed new treatment for adductor spasmodic dysphonia.

A new surgical procedure with potential application for the treatment of adductor spasmodic dysphonia was performed on ten rabbits to assess surgical effects on laryngeal function. Using an external approach, partial unilateral thyroarytenoid (TA) muscle excision was performed through a thyroplasty cartilage window. The contralateral side was left undisturbed as a control. The animals were studied acutely and at 3 months using videolaryngoscopy. Electrophysiologic measurements were recorded at 3 months. The procedure was well tolerated by all animals, with no postoperative infection or aspiration. At 3 months, spontaneous and evoked (recurrent laryngeal nerve stimulation) TA muscle electromyographic potentials were measurable bilaterally. TA compound muscle action potential amplitudes were reduced on the side of myectomy. The threshold of recurrent laryngeal nerve stimulation needed to produce observable vocal fold adduction was increased on the side operated on. Perioperative and long-term (3 months) videolaryngoscopy demonstrated preservation of laryngeal competence with good true vocal cord adduction. Histologic analysis with whole organ sections showed replacement of excised muscle with loose fibroareolar tissue. No evidence of muscle regeneration was observed. The vocal ligament and vocal fold mucosa were intact and undistorted in all specimens. This procedure is technically simple and appears to effectively result in a functional yet weakened TA muscle. Because myectomy includes motor unit end-plate excision, problems associated with reinnervation may be circumvented. TA myectomy may be applicable in patients with focal laryngeal dystonia to decrease muscle spasm.

Selected temporal aspects of coordination during fluent speech of young stutterers.

The purpose of this study was to compare the onsets, offsets, and durations of respiratory, articulatory, and laryngeal behaviors associated with the perceptually fluent speech of young stutterers (n = 8) to those of their normally fluent peers (n = 8). Simultaneous recordings of the targeted behaviors were made using noninvasive, minimally intrusive instrumentation. Specific temporal parameters of coordination--onsets, offsets, and durations of muscle activity and structural movement--were assessed within a particular component of the speech production system (e.g., onset of lower lip closing relative to lower lip opening muscle activity) as well as between different components (e.g., onset of rib cage deflation relative to onset of vocal fold contact for voicing). Results indicated that there were neither statistically significant nor apparent differences between the perceptually fluent speech of young stutterers and that of their normally fluent peers in terms of selected temporal characteristics of coordination. Findings suggest that the molar temporal characteristics of coordination for young stutterers' fluent speech production(s) are not appreciably different from those of their normally fluent peers and further, any temporal characteristics of stutterers' fluent speech that do differ from normal are probably brief, as well as subtle, in nature.

Phonatory airflow analysis in patients with laryngeal disease.

Phonatory airflow was recorded in 150 patients with various laryngeal diseases and in 60 persons with normal voices. All subjects produced several sustained vowels at different loudness levels. Disturbances of voice due to laryngeal disease may be manifested as variations of mean flow (DC), alternating flow (AC), or as a variation in the amplitude of the frequency components of the airflow signal (frequency spectra). The quantification of airflow characteristics is important if the clinician is to have a better understanding of laryngeal disease. Furthermore, preoperative and postoperative analysis can serve to document therapeutic effectiveness.

The effect of tracheostomy on posterior cricoarytenoid muscle.

It has been reported previously that the amount of electromyographic (EMG) potential of the posterior cricoarytenoid (PCA) decreases after prolonged tracheostomy. It is, therefore, reasonable to assume that a significant alteration of the biochemical characteristics of this muscle would also occur. In addition to histochemical analysis, endoscopic and EMG data were recorded to give a direct comparison in each subject. Seven male beagles were used for this study. Four were tracheostomized and three served as controls. They were examined immediately before and after surgery and again after 4 weeks by EMG and endoscopic techniques. Histochemical staining was performed on each subject. All three modalities failed to demonstrate a substantial difference between the controls and the experimental dogs.

Evaluating vocal fold function.

In the effort to develop a non-invasive method for the evaluation of the vibratory characteristics of the vocal folds in patients with vocal pathology, some of the newer methods for evaluating vocal function in normal speech are being considered. Inverse filtering of the glottal airflow waveform and ways of measuring vocal fold contact area are described and evaluated for their potential use in the clinic. Knowledge of the vibratory behavior of a patient's vocal folds is important to our understanding of problems such as spastic dysphonia, dysphonia plica and functional aphonia as well as the problems of the professional voice user.

The cry characteristics of an infant who died of the sudden infant death syndrome.

Fourteen cries of a four day old infant who subsequently died suddenly of unexplained causes were analyzed on nine acoustic characteristics including fo, duration, formant frequencies and sound pressure level. In comparison to a group of newborn controls, the Sudden Infant Death Syndrome (SIDS) victim's cries exhibited a lower fo, longer duration, lower formant frequencies and greater sound pressure level throughout the spectrum. Cry duration and sound pressure levels, however, deviated in excess on one standard deviation from the mean of the other newborns. Similar findings resulted when the SIDS infant was compared to a group of full term infants who were siblings of SIDS victims, although the magnitude of the differences was slightly less especially with respect to sound pressure level. Measurement of selected acoustic variables in a newborn's cry may be of value in our understanding of SIDS and for identifying infants at risk.

Voice change after radiotherapy. Some preliminary results.

A one-third octave spectral analysis was performed on two sentences spoken by 5 patients with laryngeal cancer, 5 with head/neck cancer not involving the vocal cords, and 12 normal subjects. Recordings were made prior to and at weekly intervals during radiotherapy as well as at periodic intervals post-treatment. Patients with laryngeal cancer exhibited lower spectral levels than normal throughout radiotherapy as well as several months post-treatment. By one year after treatment, the spectral levels of these patients were largely in the normal range. Patients with head/neck cancer not involving the vocal cords exhibited greater than normal sound pressure levels throughout most of the spectrum. These levels remained high even at one month post-treatment. Irradiation of normal vocal cord tissue also seems to result in higher spectral levels.