Multidimensional acoustic analysis for evaluation of voice quality of unilateral vocal fold paralysis

Unilateral vocal fold paralysis (UVFP) can be managed by injection laryngoplasty using different implant materials. To observe the long-term results of hyaluronic injection for unilateral vocal fold paralysis, acoustical measures including the glottal to noise excitation (GNE), vocal fold excitation ratio (VFER), glottis quotient (GQ) and mel frequency cepstral coefficients (MFCC) were obtained from the sustained vowel /a/ produced by twelve native Cantonese UVFP patients, in order to objectively evaluate the therapeutic efficacy during three time points: before treatment, during treatment, and post recovery from UVFP. Results showed that GNE and VFER were sensitive to vocal quality differences after laryngoplasty. High specificity of these acoustical measures in distinguishing voice quality before and after surgery was found, indicating that energy distribution analysis and glottis vibrational measures could be used a supplemental tool to traditional acoustic analysis, and if combined, an effective monitoring tool for UVFP treatment.