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

Motor preparation processes in Parkinson's disease (PD) patients and elderl y 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 k inematics revealed that in contrast to controls, PD patients showed a prolo ngation of the transport phase related to the validity of the object size p recue when grasping small objects. Therefore, PD patients seem to suffer fr om a slowing of their qualitatively preserved motor preparation process whi ch becomes more pronounced in complex tasks like prehension. This finding o f 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. (C) 1999 Elsevie r Science Ltd. All rights reserved.