Effects of virtual reality training on functional reaching movements in people with Parkinson's disease: a randomized controlled pilot trial

Objective: To investigate whether practising reaching for virtual moving targets would improve motor performance in people with Parkinson's disease. Design: Randomized pretest-posttest control group design. Setting: A virtual reality laboratory in a university setting. Participants: Thirty-three adults with Parkinson's disease. Interventions: The virtual reality training required 60 trials of reaching for fast-moving virtual balls with the dominant hand. The control group had 60 practice trials turning pegs with their non-dominant hand. Main outcome measures: Pretest and posttest required reaching with the dominant hand to grasp real stationary balls and balls moving at different speeds down a ramp. Success rates and kinematic data (movement time, peak velocity and percentage of movement time for acceleration phase) from pretest and posttest were recorded to determine the immediate transfer effects. Results: Compared with the control group, the virtual reality training group became faster (F = 9.08, P = 0.005) and more forceful (F = 9.36, P = 0.005) when reaching for real stationary balls. However, there was no significant difference in success rate or movement kinematics between the two groups when reaching for real moving balls. Conclusion: A short virtual reality training programme improved the movement speed of discrete aiming tasks when participants reached for real stationary objects. However, the transfer effect was minimal when reaching for real moving objects.