Stroboscopic and Multiparametric Acoustic Analysis of Voice after Vocal Loading Task

Abstract

Introduction: Voice overuse may result in roughness, fatigue and pain while speaking. Vocal loading tasks have been used to assess changes in voice quality under different controlled settings. This study was done to document changes in voice characteristics before, immediately and 24 hours post-vocal loading task (VLT) using stroboscopic and acoustic analysis. Materials and methods: Ten healthy adult males (age range: 20 to 40 years) with no apparent comorbid illness participated in the study. They were instructed to read the standard Rainbow passage at intensity above 75 dB SPL until they perceived any symptoms of fatigue/ strain. Stroboscopy and comprehensive voice assessment were done on all subjects before, immediate post VLT and 24 hours post VLT. Results: Symptoms of vocal fatigue were noted on an average of 45 minutes of loud reading. Vocal fold edema, ventricular band hyperadduction and arytenoid congestion were noticed in immediate post task. The vocal fold movements were asymmetric and aperiodic with reduced mucosal wave and amplitude. Maximum phonation time (MPT) revealed statistically significant decrease (approximately 7 sec). Multipara-metric acoustic analysis revealed a statistically significant increase in fundamental frequency, perturbation measures and lowest intensity with significant decrease in dysphonia severity index (DSI). All parameters (stroboscopic findings, perceptual, aerodynamic and acoustic analysis) showed values within normal limits after 24 hours post-task indicating recovery at 24 hours after vocal loading. Stroboscopy served as an evidence for structural and functional changes in the vocal fold. Changes in voice characteristics and recovery following vocal loading task can be documented using comprehensive voice assessment.