[Impaired associated movement in Parkinson's disease]

We analyzed the intended voluntary movement and simultaneously occurring automatic associated movement in Parkinson's disease(PD). We studied wrist dorsiflexion as a movement associated with grip and Bell's phenomenon(upward rolling of the eyeballs on forcible closure of the eyelids) in patients with PD and normal controls. The patients showed significantly smaller wrist dorsiflexion and upward rolling of the eyeballs. Patients with PD have a greater reduction of automatic associated movement than intended voluntary movement. This discrepancy between the associated movement and voluntary movement may be one of the bases of clinical symptoms of PD patients in early stage.