Huntington's disease affects movement termination

Huntington's disease (HD) is a neurodegenerative disease affecting the striatum and associated with deficits in voluntary movement in early stages. The final portion of aiming movements is particularly affected in HD and one hypothesis is that this deficit is linked to attention or terminal control requirements. Sixteen patients with early HD and 16 age-matched controls were examined in aiming movements. Four conditions manipulated movement termination requirements (discrete movements with a complete stop vs. cyclical back-and-forth movements) and the presence of flankers around the target. Reducing movement termination requirements significantly attenuated deficits in the final movement phase in patients. The presence of flankers around the target affected the initial portion of movements but did not affect the two groups differentially. These results indicate that terminal control requirements affect voluntary movements in HD. This suggests that frontostriatal systems are involved in movement termination.