Abstract: Objective To investigate the neural mechanisms of speech motor control in individuals with Parkinson's disease (PD) under different strategies of motor execution control.MethodsThe techniques of the psychoacoustic and event-related potentials (ERPs) based on the altered auditory feedback paradigm were used in the present study. Two groups, including 17 PD patients and 17 healthy controls, were instructed to produce sustained vowels under the internal and external cueing tasks while hearing their voice randomly pitch-shifted downwards. The vocal responses and associated ERPs were recorded and compared across the groups and tasks.ResultsBehavioral results showed that the amplitude of acoustic compensation response was larger in PD patients than in the healthy controls (F=5.415, P=0.027), however, the main effect was not significant in the tasks (F=0.039, P=0.840). At the cortical level, PD patients produced significantly larger N1 responses to pitch perturbations in the internal cueing task related to the external cueing task (F=8.634, P=0.006), while such task effect was not observed in the healthy controls (F=1.550, P=0.231). Also, PD patients produced significantly larger N1 responses than the healthy controls in the internal cueing condition (F=5.476, P=0.026), but not in the external cueing condition (F=0.249, P=0.621). Conclusion Speech motor control in PD can be influenced by the strategies of motor execution control. Compared to the internal cueing task, the external cueing task can increase neural efficiency in the encoding of speech auditory feedback PD patients that improve auditory-motor integration for speech production.

Key words: Parkinson's disease, motor execution control, speech motor control, vocal compensation, event-related potentials