Abstract:
At least 70% of people with PD will have speech difficulties that can restrict the quality of life by limiting the ability, and willingness, to participate in conversations (Benedetto et al., 2009) Skoda et al., (2009). Parkinsonian speech or hypokinetic dysarthria results from an impairment of phonation and articulation. There is growing evidence that people with Parkinson's disease experience changes in emotional prosody processing and show alterations of emotional speech production. Outside of the intrinsic pleasure attached to singing, the aim of this study was to look for evidence that voice and choral singing therapy (VCST) could benefit people with Parkinson’s disease (PD) and prove to be an effective means of improving and maintaining voice dynamics (phonation and prosody) and also to determine if the pleasure inherent in singing enhances the therapeutic effect. Specifically, the study set out to determine the extent to which people with PD in a choir differ in production and comprehension of affective prosody in comparison to people with PD with no exposure to VCST. An experimental group consisting of choir members with PD n=9 (male=5, female=4, average age=69.6) were tested at four intervals over a 12 month period using acoustic and perceptual analysis of voice and measures of comprehension and PD symptom severity. The results were compared to the results of a control group consisting of non-choir members with PD (N=6, male=5, female=1, average age=76.3). This longitudinal study investigated whether VCST affected change in prosody processing, improved prosodic production and queried whether the emotional uplift of singing and the choir community or ‘reward related behaviour’ interfered positively on dopaminergic pathways. The study protocol included multiple prosody production and comprehension tasks in order to enhance our understanding of the affective prosodic deficits associated with PD. We found significant differences between the two groups. Over the test period improvement occurred in MPT, SPL, voice quality (shimmer) and measures of PD symptom severity for the EG but not the CG. We found significant between-group differences in mean F0, however, this could be attributable to a gender imbalance. There were no significant betweengroup differences for prosody comprehension or production, which might reflect shortcomings in the study design and tasks of insufficient sensitivity.
