The basal ganglia are involved in the performance of upper-limb bimanual coordination movements. The purpose of this study was to examine the influence of basal ganglia impairments, as manifested in Parkinson's disease (PD), on the capability of perfo...
The basal ganglia are involved in the performance of upper-limb bimanual coordination movements. The purpose of this study was to examine the influence of basal ganglia impairments, as manifested in Parkinson's disease (PD), on the capability of performing bimanual coordination depending on the presentation of external cues. Ten PD patients in advanced stages and 10 early stages of untreated PD patients, and 10 age-matched normal controls were instructed to perform bimanual coordination movements at 3 different speeds (0.75, 1.25, 1.78Hz). The results demonstrated that only advanced PD patients exhibited a reduced synchronized coordination during the anti-phase mode, particularly at the fastest speed (i.e., 1.75 Hz), compared with other two subject groups. This finding suggests that the observed bimanual coordination dysfunction in PD may be developed over the disease progression or a side effect of dopaminergic medication. The present study also examined the parameterization of individual limb movements such as speed, amplitude, and smoothness of each limb movement, independent of the coordinative requirements of in-phase and anti-phase patterns. The results showed that both PD patient groups showed impairments in scaling movement speed and amplitude of limb, and these deficits were more pronounced as a function of movement frequency. This indicates that difficulties in parameterizing the individual limb movements during bimanual coordination could be an early sign of the pathophysiology of the disease.