Abstract
Objectives
To compare the degree of dysphonia's severity with the latency between the electrophysiological activation of the TA muscle and the phonation onset in patients with adductor laryngeal dystonia.
Methods
21 patients with adductor dystonia and 15 controls underwent laryngeal electromyography (EMG) exam of the left TA muscle. The latency time was registered from rise of the electric activity of the TA muscle until the phonation onset. Perceptual evaluation of voice quality was performed for the study group and judged by consensus of three speech-pathologists/voice specialists. The evaluation considered 4 tasks: 1) sustained vowel /e/ in habitual pitch and loudness; 2) sustained vowel /i/ in ascending and descending glissando; 3) sustained vowel /i/ at high pitch; 4) phrases including words with voiced and voiceless phonemes. The dysphonia's severity degree was classified in the following scale: 0 -; no alteration perceived; 1 -; mild degree; 2 -; moderate degree; 3 -; severe degree. The Spearman's Correlation Test was used to compare the latency time values and the dysphonia's severity degree (p<0,05).
Results
The average latency time registered for patients with mild dysphonia was 332ms, for moderate dysphonia it was 426ms, and for the severe group was 791ms (p=0.02*).
Conclusions
The latency time was significantly and directly related to the degree of dysphonia's severity.
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