Effects of Vocal Loading Task and Hydration on Voice Quality in Adults from Kerala

Abstract

Vocal fold hydration is essential for optimal voice production. This study aimed to understand the effects of systemic and surface hydration on acoustic and perceptual voice measures following a vocal loading task in adults aged 18-58 years. A total of 40 healthy adults (20 males, 20 females) were divided into two age groups (18-38 years and 38-58 years). Participants completed a 45-minute vocal loading task, followed by either systemic hydration (oral fluid intake) or surface hydration (5-minute isotonic saline nebulization). Acoustic parameters (F0, jitter, shimmer, HNR) were measured using PRAAT software and perceptual measures were assessed using the Vocal Fatigue Index (VFI) and Vocal Tract Discomfort Scale (VTDS) at pre-fatigue, post-fatigue and post-hydration conditions. The result showed that Vocal loading significantly increased F0, jitter and shimmer while decreasing HNR indicating vocal fold instability and breathiness. Both hydration types restored all acoustic parameters to near-baseline levels with no significant differences between systemic and surface hydration. Perceptual scores (VFI and VTDS) showed highly significant increases post-fatigue and returned to baseline after hydration. No significant age-group differences were observed for most parameters, though gender differences were noted for F0 and jitter. Hence, both systemic and surface hydration are equally effective in mitigating vocal fatigue and restoring vocal function following vocal loading. These findings support incorporating both hydration strategies into vocal hygiene programs for voice professionals and individuals at risk of vocal fatigue.