Motor speech versus digit control in Parkinson's disease: A cognitive neuropsychology investigation

Motor speech and digit tapping deficits are well-documented in idiopathic Parkinson's Disease (PD); this study focuses on the relationship between the two. Despite the fact that motor aspects are present in both tasks, significant dissociations between them are reported. Parkinson's Disease patients were slow at finger tapping and rapid syllable repetition. They also showed reduced fundamental frequency ranges when humming. Performance on verbal fluency ranged from intact to impaired, and dissociated doubly with rapid articulation. Finger tap values correlated significantly with disease severity, but not with single syllable repetition, or with verbal fluency rates.