The cerebellum in dual-task performance in Parkinson's disease.

Parkinson's disease (PD) patients have difficulty in performing a dual-task. It has been suggested that the cerebellum is important in dual-tasking. We used functional MRI to investigate the role of the cerebellum in performing a dual motor and cognitive task in PD patients. We have examined whether there are any areas additionally activated for dual-task performance, and compared the neural activity and functional connectivity pattern in the cerebellum between PD patients and healthy controls. We found that the right cerebellar vermis and left lobule V of cerebellar anterior lobe were additionally activated for dual-task performance in healthy controls and for motor task in PD patients. We didn't find any cerebellar regions additionally activated while performing dual-task in PD patients. In addition, the right cerebellar vermis had enhanced connectivity with motor and cognitive associated networks in PD patients. PD patients have limited cerebellar resources that are already utilized for single tasks and, for dual tasks, cannot augment as necessary in order to integrate motor and cognitive networks.