Air pulse deformation measurement: a preliminary method for noninvasive vocal fold pliability analysis.

OBJECTIVE: A new method, air pulse pliability measurement, is presented, with which the pliability and elasticity of the vocal folds was measured in vitro and in vivo using air pulses. The size of the mucosal movements induced by air pulse stimulation was measured with a laser-based technique. SUBJECTS AND METHODS: The air pulses fed via a 2-mm tubing, introduced through the working channel of a flexible endoscope. Both in vitro and in vivo tests were performed. Nine normal, vocally healthy subjects were examined by air pulse stimulations of the vocal folds, of the skin (cheek and dorsum of the hand) and of the inside of the lips. RESULTS: The in vitro tests showed a coefficient of variation of 5% within a range of 1-5 mm from the probe to the surface. The elasticity data showed no differences between vocal folds, lips or cheek. The hand data showed a significantly higher stiffness as compared to the other 3 measuring points (p < 0.001). The coefficient of variation was about 35% for all measuring points, but in ideal conditions on skin it was 9%. CONCLUSION: The results show that the technique allows automatic, quantitative, noninvasive vocal fold pliability measurements on awake subjects.

Is pseudosulcus alone a reliable sign of gastroesophago-pharyngeal reflux?

To investigate if laryngeal pseudosulcus (bilateral infraglottic oedema) is a reliable sign of pharyngeal reflux, the video recordings of 59 patients and 18 controls were examined off-line by two phoniatricians. Eleven video segments were duplicated for calculation of intrarater reliability. The frequency of pseudosulcus was correlated to the results of 24-h double-probe pH monitoring. The intrarater reliability was moderate (K = 0.582; P = 0.005). The sensitivity of pseudosulcus in the diagnosis of pharyngeal reflux among the patients was 30% and among the controls it was 0%. The positive predictive value (PPV) of pseudosulcus for patients with pharyngeal and laryngeal symptoms was 67%, while for the controls it was 0%. The negative predictive value (NPV) of pseudosulcus for patients with pharyngeal or laryngeal symptoms was 32% and for the controls it was 64%. The single finding of pseudosulcus is not a very sensitive predictor of pharyngeal reflux but if the patient has laryngeal symptoms and a pseudsulcus, the probability that the patient has pharyngeal reflux is almost 70%.

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.

Vocal fold deposits in autoimmune disease--an unusual cause of hoarseness.

The objective of this study was to evaluate the symptoms and clinical characteristics in patients with autoimmune vocal fold deposits. Fourteen patients underwent videolaryngostroboscopic examination and voice recording. Eleven of the 14 patients underwent rheumatological examination. In all cases, endoscopic examination showed transverse white-yellow band lesions in the middle of the membranous portion of the vocal folds. In most cases, the lesions were bilateral but not exactly opposing each other. The most common voice characteristics were instability and intermittent aphonia. Inflammatory disease was present in 10 patients; five of these had rheumatoid arthritis (RA). No immunological signs common for all patients could be found. The histological examination was consistent with rheumatoid nodules. Vocal fold deposits, occurring most often in patients with RA, is an uncommon cause of hoarseness. Because the patients may have hoarseness as their primary symptom, it is important for otolaryngologists to be familiar with this disorder.

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). STUDY DESIGN: A prospective controlled study. METHODS: Nineteen healthy control subjects and 43 patients, 26 with posterior laryngitis (PL) and 17 with a normal larynx and suspected GEPR, were examined using videolaryngoscopy and 24-hour ambulatory dual-probe pH monitoring. RESULTS: Pharyngeal acid reflux occurred in 18 (69%) patients with PL, in 9 (53%) patients with a normal larynx, and in 5 (26%) healthy control subjects. Multiple-comparison procedure showed that pharyngeal reflux was significantly more prevalent in patients with PL than in the healthy control subjects (P < .05). The laryngoscopic findings in patients with pharyngeal reflux varied from normal mucosa to thickening or edema of the posterior wall of the glottis, which was the most frequent finding in the PL group. Erythema was uncommon; it was found only in patients with verified pharyngeal reflux. There was no difference in symptom profile between the patients with PL and patients with a normal larynx or patients with or without pharyngeal reflux. CONCLUSIONS: Pharyngeal reflux is significantly more prevalent in patients with posterior laryngitis than in healthy control subjects. Moreover, a certain degree of pharyngeal reflux appears to be a normal phenomenon. The most common laryngeal finding in patients with posterior laryngitis is thickening or edema of the posterior wall of the glottis. GEPR does not yield specific laryngeal symptoms. Thus, it is unreliable to base the reflux diagnosis on symptoms alone.

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.

Voice source characteristics in Mongolian "throat singing" studied with high-speed imaging technique, acoustic spectra, and inverse filtering.

Mongolian "throat singing" can be performed in different modes. In Mongolia, the bass-type is called Kargyraa. The voice source in bass-type throat singing was studied in one male singer. The subject alternated between modal voice and the throat singing mode. Vocal fold vibrations were observed with high-speed photography, using a computerized recording system. The spectral characteristics of the sound signal were analyzed. Kymographic image data were compared to the sound signal and flow inverse filtering data from the same singer were obtained on a separate occasion. It was found that the vocal folds vibrated at the same frequency throughout both modes of singing. During throat singing the ventricular folds vibrated with complete but short closures at half the frequency of the true vocal folds, covering every second vocal fold closure. Kymographic data confirmed the findings. The spectrum contained added subharmonics compared to modal voice. In the inverse filtered signal the amplitude of every second airflow pulse was considerably lowered. The ventricular folds appeared to modulate the sound by reducing the glottal flow of every other vocal fold vibratory cycle.

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. STUDY DESIGN: A Weinberger Speedcam + 500 system (Weinberger AG, Dietikon, Switzerland) was used with a frame rate of 1,904 frames per second. Images were stored and analyzed digitally. Analysis included automatic glottal edge detection and calculation of glottal area variations, as well as kymography. These signals were compared with acoustic waveforms using the Soundswell program (Hitech Development AB, Stockholm, Sweden). METHODS: The High-Speed Tool Box was applied on two types of high-speed recordings: a diplophonic phonation and a tremor voice. Relations between glottal vibratory patterns and the sound waveform were analyzed. RESULTS: In the diplophonic phonation, the glottal area waveform, as well as the kymogram, showed a specific pattern of repetitive glottal closures, which was also seen in the acoustic waveform. In the tremor voice, fundamental frequency (F0) fluctuations in the acoustic waveform were reflected in slow variations in amplitude in the glottal area waveform. For studying details of mucosal movements during these kinds of abnormal vibrations, the glottal area waveform was particularly useful. CONCLUSIONS: Our results suggest that this combined high-speed acoustic-kymographic analysis package is a promising aid for separating and specifying different voice qualities such as diplophonia and voice tremor. Apart from clinical use, this finding should be of help for specification of the terminology of different voice qualities.

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.

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.