Reaching movement with purposeful activity and/or visuotemporal cue in people with Parkinson's disease

Objectives. The purpose of the study was to evaluate whether movement performance in Parkinson's disease (PD) is facilitated by having a visuotemporal cue (VTC) or by having a more purposeful activity (PA). Methods. Seventeen subjects with idiopathic PD participated. They were asked to reach and grasp a bottle that was swung back and forth or fixed in front of them for the VTC or non-VTC conditions, respectively. PA or non-PA conditions were represented by the presence or absence of money in the bottle, respectively. Kinematic measurements of the reaching movement were performed in order to evaluate the temporal and spatial characteristics. Results . In the VTC conditions, the wrist path appeared straighter and the maximal values of wrist velocity, acceleration and deceleration were lower than in the non-VTC conditions. There were no differences between the PA and non-PA conditions. Discussion. PD subjects appeared to benefit from the VTC condition for the spatial characteristics of movement. However, they showed deficits in the temporal characteristics, possibly related to a visual perception problem in PD. The lack of effect of the PA condition may have been due to an insufficient difference between the PA and non-PA conditions used. Alternatively, it may be related to impaired incentive learning in PD. Conclusion. The present design of external information led to no improvement of the movement in people with PD. The reason for this absence of improvement may be that the external information was not suitably designed in relation to the deficits of people with PD.