Correlation between acoustic speech characteristics and non-speech motor tasks in Parkinson's disease

By A.M. Goberman

Given that a relationship between speech and non-speech movement may serve to further define the neural mechanisms responsible for speech, the present study examined correlations between speech and non-speech tasks in Parkinson’s disease (PD). Ten PD patients were recorded three times each, before, one hour after, and two hours after their morning medication. Motor performance was examined using the motor portion of the UPDRS, and acoustic measures were used to examine speech. Three of eight speech measures (intensity range, articulation rate, and percent pause) were found to correlate (p<0.05) with non-speech movements. These speech measures correlated with axial symptoms (e.g., facial expression, postural stability) and bradykinesia. In addition, percent pause correlated with rest tremor. Previous studies have found that speech is correlated with non-speech axial symptoms. This study adds that not all speech measures are correlated with axial symptoms, and some measures correlated with other motor tasks. It might be more appropriate to consider that speech systems are affected differently in PD, and therefore different speech systems may be regulated / controlled separately within the brain.