For the purpose of studying the clinical characteristics of vocal fold bowing, the correlation between the quantitative analysis and vocal function tests was investigated in 287 patients with unilateral recurrent laryngeal nerve paralysis. Parameters for the quantitative analysis included patient's age, sex, period of unilateral recurrent laryngeal nerve paralysis, fixed position of the vocal fold, cause of paralysis, and degree of aspiration. For vocal function tests, phonatory parameters (MPT, MFRc, SPLrange, FOrange) and acoustic parameters (PPQ, APQ) were analyzed. The following results were obtained : 1) The vocal fold bowing ranged from 5% to 15% in most (236 of 286) cases with the average being 11.5%. 2) The degree of vocal fold bowing increased from the age group of forty or older. 3) The degree of vocal fold bowing showed a tendency to decrease from 270 days after the onset of recurrent laryngeal nerve paralysis. 4) In the vocal function tests, FOrange, PPQ, APQ showed a relationship to the degree of vocal fold bowing.
