Effects of a music therapy voice protocol on speech intelligibility, vocal acoustic measures, and mood of individuals with Parkinson's disease.

This study examined the effects of a Music Therapy Voice Protocol (MTVP) on speech intelligibility, vocal intensity, maximum vocal range, maximum duration of sustained vowel phonation, vocal fundamental frequency, vocal fundamental frequency variability, and mood of individuals with Parkinson's disease. Four female patients, who demonstrated voice and speech problems, served as their own controls and participated in baseline assessment (study pretest), a series of MTVP sessions involving vocal and singing exercises, and final evaluation (study posttest). In study pre and posttests, data for speech intelligibility and all acoustic variables were collected. Statistically significant increases were found in speech intelligibility, as rated by caregivers, and in vocal intensity from study pretest to posttest as the results of paired samples t-tests. In addition, before and after each MTVP session (session pre and posttests), self-rated mood scores and selected acoustic variables were collected. No significant differences were found in any of the variables from the session pretests to posttests, across the entire treatment period, or their interactions as the results of two-way ANOVAs with repeated measures. Although not significant, the mean of mood scores in session posttests (M = 8.69) was higher than that in session pretests (M = 7.93).