Acoustic characteristics of post-thyroplasty patients.

This study investigated changes in voice quality after thyroplasty type I in eight adults with unilateral vocal fold paralysis. A silicone rubber implant was inserted through a window in the thyroid ala and placed between the inner and outer perichondrium to externally medialize the abducted vocal fold. Measures of fundamental frequency (vocal pitch), pitch range, maximum phonation time, s/z ratio, pitch perturbation (vocal jitter), and amplitude perturbation (vocal shimmer) were made 1 to 2 weeks preoperatively and 1 month postoperatively. Postoperative voice quality was characterized by an improved pitch range, phonation time, s/z ratio, and pitch and amplitude perturbation. No change was noted in fundamental frequency. Changes in postoperative voice quality were unrelated to the subjects' preoperative age, sex, etiology, and duration of the paralysis.