Vocal function in patients with unilateral vocal fold paralysis before and after silicone injection

A total of 240 patients with unilateral vocal fold paralysis (UVFP) underwent transcutaneous intrafold silicone injection (TCIFSI) for the purpose of vocal rehabilitation during the period from 1983 to 1993 in the Kurume University Hospital. Their vocal function was evaluated and the effects of TCIFSI upon the vocal function were investigated. The patients with UVFP presented with an increase in airflow during phonation; a decrease in maximum phonation time and fundamental frequency (F0) range and sound pressure level (SPL) range of phonation; and an increase in pitch perturbation quotient, amplitude perturbation quotient and normalized noise energy in the voice signal. TCIFSI resulted in a decrease in airflow, an increase in phonation time and F0 and SPL range of phonation, and a decrease in pitch and amplitude perturbation and noise in the voice signal. Patient's own subjective evaluation presented with an improvement of his/her voice after TCIFSI.