Handle size as a task constraint in spoon-use movement in patients with Parkinson's disease

Objective: To examine the effect of spoon-handle size on kinematic performance in people with Parkinson's disease. Design: A counterbalanced repeated-measures design. Setting: A motor control laboratory in a university setting. Subjects: Eighteen individuals with Parkinson's disease and 18 age-matched controls. Experimental conditions: Each participant was instructed to scoop water (simulated soup) using spoons with three different-sized handles. Main measures: Kinematic variables (movement time, peak velocity and number of movement units) of arm movement, size of hand aperture and number of fingers to grasp the Spoon. Results: The movement of the participants with Parkinson's disease was faster (shorter movement time) and smoother (fewer movement units) when they used spoons with a small- or medium-sized handle than when using a spoon with a large-sized handle. In contrast, the healthy controls showed no significant differences in movement kinematics between handle sizes. Moreover, the participants with Parkinson's disease had a significantly smaller hand aperture and used more fingers to hold the spoons than the controls did. Conclusions: These results suggest that, for people with Parkinson's disease, a small-to-medium-sized handle is more suitable than a large-sized built-up handle.