S194 The role of the cerebellum in movement disorders

Abstract

Objectives Although movement disorders like Parkinson’s Disease (PD) or dystonia have traditionally been regarded as basal ganglia dysfunction, recent evidence has emerged of cerebellar involvement in the pathophysiology of these movement disorders. Methods Patients with PD, dystonia and healthy controls (HC) underwent fMRI during an interception of a moving target. Effective connectivity (EC) and its modulation by behavioural outcome in a network comprised of the cerebellum, BG, and other cortical areas was studied, too. Results (i) In patients with PD, despite having similar hit ratios, the PD failed more often than the HC to postpone their actions until the right moment and to adapt their behaviour from one trial to the next. We found more activation in the right cerebellar lobule VI in HC than in PD during successful trials. Successful trial-to-trial adjustments were associated with higher activity in the right putamen and lobule VI of the cerebellum in HC. (ii) In patients with dystonia, left cerebellar lobule VI was used as the seed for the psychophysiologic interaction model. In addition of lower performance in the task itself, we found decreased connectivity of the above specified seed to basal ganglia complex. Discussion We propose that PD and dystonia are a large scale dysfunction, involving not only cortico-basal ganglia-thalamo-cortical pathways, but cortico-ponto-cerebello-thalao-cortical loop as well. Significance Further research leading to the delineation of other brain areas active during this behaviour in addition to computer-based neuro-rehabilitation programs could improve the movement disorders patients performance.