Per-Åke Lindestad

Symptoms, laryngeal findings, and 24-hour pH monitoring in patients with suspected gastroesophago-pharyngeal reflux.

Objectives To investigate the laryngeal signs and symptoms associated with gastroesophago‐pharyngeal reflux (GEPR).

Vocal Fold Vibrations: High-Speed Imaging, Kymography, and Acoustic Analysis: A Preliminary Report †

Objectives To evaluate a new analysis system, High‐Speed Tool Box (H. Larsson, custom‐made program for image analysis, version 1.1, Department of Logopedics and Phoniatrics, Huddinge University Hospital, Huddinge, Sweden, 1998) for studying vocal fold vibrations using a high‐speed camera and to relate findings from these analyses to sound characteristics.

A comparison of subglottal and intraoral pressure measurements during phonation

Intraoral pressure and subglottal pressure, derived from tracheal puncture, were recorded with the electroglottographic signal for one normal speaking male during phonation. The mean subglottal pressure for vowels was also estimated by interpolating the intraoral pressure from surrounding /p/occlusions. The pressure measurements were highly correlated (r = 0.98) and there were small pressure value differences (on average < 2%). The effects of varying speech rate and mode of phonation on the pressure measurements are discussed. A decrease in pressure from the mean subglottal pressure for the open phase and an increase for the closed phase was found during the glottal vibratory cycles.

Botulinum toxin injections for essential voice tremor.

Fifteen patients, 13 women and 2 men, with a mean age of 72.7 years (56 to 86 years) and a clinical diagnosis of essential voice tremor, were treated with botulinum injections to the thyroarytenoid muscles, and in some cases, to the cricothyroid or thyrohyoid muscles. Evaluations were based on subjective judgments by the patients, and on perceptual and acoustic analysis of voice recordings. Subjective evaluations indicated that the treatment had a beneficial effect in 67% of the patients. Perceptual evaluations showed a significant decrease in voice tremor during connected speech (p < .05). Acoustic analysis showed a nearly significant decrease in the fundamental frequency variations (p = .06) and a significant decrease in fundamental frequency during sustained vowel phonation (p < .01). The results of perceptual evaluation coincided most closely with the subjective judgments. It was concluded that the treatment was successful in 50% to 65% of the patients, depending on the method of evaluation.

A method of applying Fourier analysis to high-speed laryngoscopy

A new method for analysis of digital high-speed recordings of vocal-fold vibrations is presented. The method is based on the extraction of light-intensity time sequences from consecutive images, which in turn are Fourier transformed. The spectra thus acquired can be displayed in four different modes, each having its own benefits. When applied to the larynx, the method visualizes oscillations in the entire laryngeal area, not merely the glottal region. The method was applied to two laryngoscopic high-speed image sequences. Among these examples, covibrations in the ventricular folds and in the mucosa covering the arytenoid cartilages were found. In some cases the covibrations occurred at other frequencies than those of the glottis.

A retrospective study of contact granuloma

Objectives: This study evaluates the clinical features of contact granuloma and compares the results of voice therapy in operated versus unoperated cases. Study Design: Retrospective review of 123 patients with contact granuloma. Thirty‐six patients had undergone one or more surgeries before phoniatric consultation. After their final operation, 33 patients had recurrence. The three patients who were cured by operation were not studied further. The course of disease in the 33 patients with recurrence was compared with that of 87 patients who did not have surgery. Methods: The hospital records were reviewed concerning age, sex, symptoms, side of granuloma, and outcome of treatment. Results: The predominant symptoms were vocal fatigue, vocal discomfort, the need for excessive throat clearing, and hoarseness. The recurrence rate after operation was 92%. Twelve months after voice therapy, 35% of the operated group and 51% of the unoperated group were cured. The patients who had surgery had almost twice as many sessions of voice therapy as the unoperated group, and their mean recovery time was 17 months, compared with 8 months for the unoperated group. Conclusions: The recurrence rate after surgery was high. Surgery may prolong the recovery time. Subjective symptoms diminished during voice therapy, but we cannot confirm that it was beneficial for the healing process.

Spindle-shaped glottal insufficiency with and without sulcus vocalis: a retrospective study

The clinical records of 186 patients with spindle-shaped glottal insufficiency were studied in order to evaluate the clinical background of the finding. The patients formed two main groups: those with and those without sulcus vocalis. Most of the sulcus patients were females, comparatively young at the onset of symptoms and at the time of diagnosis. In contrast, the majority of patients with spindle-shaped glottal insufficiency without sulcus were male and they often had a history of either laryngitis or chronic general disease causing decreased physical ability. Some patients in this group had long-standing symptoms, possibly caused by a disturbance in pubertal voice change. The data also indicate differences between the groups in vocal fold vibratory pattern. It is evident that the spindle-shaped glottal insufficiency observed in patients with and without sulcus has different causes and different pathophysiologic explanations.

High-speed registration of phonation-related glottal area variation during artificial lengthening of the vocal tract

Vocal exercises that increase the vocal tract impedance are widely used in voice training and therapy. The present study applies a versatile methodology to investigate phonation during varying artificial extension of the vocal tract. Two males and one female phonated into a hard-walled plastic tube (φ 2 cm), whose physical length was randomly pair-wise changed between 30 cm, 60 cm and 100 cm. High-speed image (1900 f/sec) sequences of the vocal folds were obtained via a rigid endoscope. Acoustic and electroglottographic signals (EGG) were recorded. Oral pressure during shuttering of the tube was used to give an estimate of subglottic pressure (Psub). The only trend observed was that with the two longer tubes compared to the shortest one, fundamental frequency was lower, open time of the glottis shorter, and Psub higher. The results may partly reflect increased vocal tract impedance as such and partly the increased vocal effort to compensate for it. In other parameters there were individual differences in tube length-related changes, suggesting complexity of the coupling between supraglottic space and the glottis.

Laryngeal Findings in Patients with Contact Granuloma: a Long-Term Follow-Up Study

In order to evaluate the long-term outcome of contact granuloma a follow-up study of 59 patients was conducted. Primary treatment consisted mainly of voice therapy or of voice therapy in combination with surgery. A careful history was taken and the patients were examined using videolaryngoscopy. The average follow-up time was 12 years (range 5-20 years). In total, 10 out of 59 patients (17%) had a granuloma at the follow-up examination, 6 of them presenting without subjective symptoms. Another 28 patients had various signs of inflammation of the posterior glottis. The history taken at follow-up revealed that eight patients had had a previous temporary recurrence during the follow-up time. The recurrence frequency was the same for patients who received voice therapy after postoperative recurrence and patients who were treated with voice therapy only. About 80% of the patients had no symptoms at follow-up. The findings of the present study indicate that contact granuloma is one of several manifestations of chronic posterior laryngitis and that it may occur without symptoms.

Vocal fold vibration and voice source aperiodicity in 'dist' tones: a study of a timbral ornament in rock singing

The acoustic characteristics of so-called ‘dist’ tones, commonly used in singing rock music, are analyzed in a case study. In an initial experiment a professional rock singer produced examples of ‘dist’ tones. The tones were found to contain aperiodicity, SPL at 0.3 m varied between 90 and 96 dB, and subglottal pressure varied in the range of 20–43 cm H2O, a doubling yielding, on average, an SPL increase of 2.3 dB. In a second experiment, the associated vocal fold vibration patterns were recorded by digital high-speed imaging of the same singer. Inverse filtering of the simultaneously recorded audio signal showed that the aperiodicity was caused by a low frequency modulation of the flow glottogram pulse amplitude. This modulation was produced by an aperiodic or periodic vibration of the supraglottic mucosa. This vibration reduced the pulse amplitude by obstructing the airway for some of the pulses produced by the apparently periodically vibrating vocal folds. The supraglottic mucosa vibration can be assumed to be driven by the high airflow produced by the elevated subglottal pressure.