Vocal impact of a prolonged reading task at two intensity levels : Perceptual analysis

Our goal is to evaluate the impact on voice of both duration and intensity level of 2 hours of continuous oral reading. Fifty normophonic women underwent two sessions of voice loading in which the required intensity level of voice varied: 60-65 dB(A) for the first session, and 70-75 dB(A) for the second session. Objective measurements and subjective self-ratings were presented in a previous study (Remacle, Finck, Roche & Morsomme, 2012). Here are the results of perceptual analysis based on comparative judgments.

Ten expert listeners evaluated the pressedness and the breathiness of one sentence recorded before and after each loading session. Pairs of stimuli were presented randomly to listeners who were asked to designate the most pressed sample at a first listening and the most breathy sample at a second listening. Each pair of stimuli was presented twice in order to evaluate the reliability.

Results indicate that inter-judges and intra-judges reliability was poor to fair.
Concerning the duration effect of vocal loading, results showed a significant decrease of breathiness but no change of pressedness after reading in both sessions. The decreased breathiness represents a voice improvement which could be interpreted as an adaptation of voice to loading. When comparing the two intensity levels, no difference was found for breathiness and pressedness after vocal loading. Similarly to objective measurements and self-ratings, perceptual assessments suggest that the duration of vocal loading has more effects on voice than its intensity level.