SPECTRAL, CEPSTRAL AND APERIODICITY CHARACTERISTICS OF PATHOLOGICAL VOICES BEFORE AND AFTER PHONOSURGICAL TREATMENT

Objective and quantitative acoustic parameters are useful-in addition to perceptual evaluation-for assessing the results of voice surgery. Thirty-two patients with different kinds of benign vocal fold lesions and ten patients who had Teflon injection in a paralysed vocal fold were investigated just before and a few months after surgery. In each case we measured in a sustained /a/: relative high-frequency noise, jitter ratio, and magnitude of dominant cepstrum peak. Paired values of all three parameters demonstrate a statistically significant improvement. The degree of aperiodicity and the excess of high-frequency noise appear to be frequently influenced in a very different way by the surgical treatment. However, the magnitude of the main cepstrum peak, which is sensitive to both components, reaches the best statistical significance score for demonstrating functional improvement after surgery.