Fig. 2.

Peak tangential velocity of the hand during the reach averaged across vision conditions for the five targets. Error lines combine standard errors of the mean within and across subjects. The inset shows a frontal projection of the target space. Controls exhibit the fastest reaches, PD patients Off STN DBS the slowest, and patients On STN DBS show intermediate speeds. Thus, PD patients, as expected, show bradykinesia, which is significantly improved with STN DBS.