Sensorimotor Impairment of Speech and Hand Movement Timing Processing in Parkinson's Disease

Models of motor control have highlighted the role of temporal predictive mechanisms in sensorimotor processing of speech and limb movement timing. We investigated how these mechanisms are affected in Parkinson's disease (PD) while patients performed speech and hand motor reaction time tasks in response to sensory stimuli with predictable and unpredictable temporal dynamics. Results showed slower motor reaction times in PD vs. control in response to temporally predictable, but not unpredictable stimuli. This effect was driven by faster motor responses to predictable stimuli in control subjects; however, no such effect was observed in the PD group. These findings indicated the relationship between PD pathology and sensorimotor deficits in temporal predictive mechanisms of timing processing during speech production and hand movement.