Grip force scaling and sequencing of events during a manipulative task in Huntington's disease

Thr aim of the study was to investigate force regulation and sequencing of events in Huntington's disease (HD) patients when performing a drawer opening task using the precision grip. Results revealed that HD patients used excessive grip force levels that were unrelated to the actual task demands. Also. they demonstrated a higher grip force value at load force onset in addition to an increased delay between initiation of grip force and load (pulling) force. These data indicate a deficit in the coordinated activation of both forces due to HD. Furthermore, the patients showed bradykinesia along with a prolonged interval between the movement phases underlying the task, denoting an impairment in encoding serially ordered events. Together. these results illustrate the deteriorating effect of striatal pathology on manual function. Accordingly, an amended control of grasping forces and serial encoding of movement-related events due to HD are likely to affect the proficiency of common manipulative skills. (C) 2001 Elsevier Science Ltd. All rights reserved.