Use of advance information for complex movements in Parkinson's disease

Motor preparation processes in Parkinson's disease (PD) patients and elderly control subjects were examined by utilizing the movement parameter precue technique in prehension movements to different sized objects. PD patients as well as controls were able to use advance information about object size to reduce their response times. However, further analysis of the response kinematics revealed that in contrast to controls, PD patients showed a prolongation of the transport phase related to the validity of the object size precue when grasping small objects. Therefore, PD patients seem to suffer from a slowing of their qualitatively preserved motor preparation process which becomes more pronounced in complex tasks like prehension. This finding of a qualitatively preserved, but slowed capability in PD patients of using advance information for motor preparation is discussed in the framework of the motor control literature on predictive behavior in PD.