OBJECTIVE: To compare the performance of reaching for stationary and moving targets in virtual reality (VR) and physical reality in persons with Parkinson's disease (PD). DESIGN: A repeated-measures design in which all participants reached in physical reality and VR under 5 conditions: 1 stationary ball condition and 4 conditions with the ball moving at different speeds. SETTING: University research laboratory. PARTICIPANTS: Persons with idiopathic PD (n=29) and age-matched controls (n=25). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Success rates and kinematics of arm movement (movement time, amplitude of peak velocity, and percentage of movement time for acceleration phase). RESULTS: In both VR and physical reality, the PD group had longer movement time (P<.001) and lower peak velocity (P<.001) than the controls when reaching for stationary balls. When moving targets were provided, the PD group improved more than the controls did in movement time (P<.001) and peak velocity (P<.001), and reached a performance level similar to that of the controls. Except for the fastest moving ball condition (0.5-s target viewing time), which elicited worse performance in VR than in physical reality, most cueing conditions in VR elicited performance generally similar to those in physical reality. CONCLUSIONS: Although slower than the controls when reaching for stationary balls, persons with PD increased movement speed in response to fast moving balls in both VR and physical reality. This suggests that with an appropriate choice of cueing speed, VR is a promising tool for providing visual motion stimuli to improve movement speed in persons with PD. More research on the long-term effect of this type of VR training program is needed.
OBJECTIVE: To compare the performance of reaching for stationary and moving targets in virtual reality (VR) and physical reality in persons with Parkinson's disease (PD). DESIGN: A repeated-measures design in which all participants reached in physical reality and VR under 5 conditions: 1 stationary ball condition and 4 conditions with the ball moving at different speeds. SETTING: University research laboratory. PARTICIPANTS: Persons with idiopathic PD (n=29) and age-matched controls (n=25). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Success rates and kinematics of arm movement (movement time, amplitude of peak velocity, and percentage of movement time for acceleration phase). RESULTS: In both VR and physical reality, the PD group had longer movement time (P<.001) and lower peak velocity (P<.001) than the controls when reaching for stationary balls. When moving targets were provided, the PD group improved more than the controls did in movement time (P<.001) and peak velocity (P<.001), and reached a performance level similar to that of the controls. Except for the fastest moving ball condition (0.5-s target viewing time), which elicited worse performance in VR than in physical reality, most cueing conditions in VR elicited performance generally similar to those in physical reality. CONCLUSIONS: Although slower than the controls when reaching for stationary balls, persons with PD increased movement speed in response to fast moving balls in both VR and physical reality. This suggests that with an appropriate choice of cueing speed, VR is a promising tool for providing visual motion stimuli to improve movement speed in persons with PD. More research on the long-term effect of this type of VR training program is needed.