The effect of the Myomo robotic orthosis on reach performance after stroke

Abstract

Stroke affects 795,000 people yearly. Close to 85 percent of stroke survivors experience some degree of stroke-related upper extremity impairment due to spastic paresis (Nakayama, Jorgenson, Pedersen, Raaschou, & Olsen, 1994). Residual upper extremity impairments are associated with increased burden of care (Skidmore, Rogers, Chandler, & Holm, 2006) and decreased ability to garner gainful employment (Desrosiers et al., 2006). Current best evidence supports the use of a task-oriented practice regimen for the treatment of upper extremity impairment; however, many people have insufficient motor control to participate. It was the goal of this study to investigate the effect of the Myomo robotic upper extremity orthosis, a device that facilitates participation in a task-oriented practice regimen, on reach kinematic performance. Specifically, we examined two research questions: Question 1. What is the immediate effect of the Myomo orthosis on kinematic performance of reach? We predicted that before training, temporal (movement efficiency) and spatial characteristics (angular displacement, movement error, and acceleration cycles) of kinematic performance would be better with the Myomo orthosis than without the device. Question 2. What is the training effect of the Myomo orthosis plus training kinematic performance? We predicted that temporal (movement efficiency) and spatial characteristics (angular displacement, movement error, and acceleration cycles) of kinematic performance without the Myomo orthosis would be better after 16 training sessions. Findings suggest that the immediate effect of the Myomo orthosis on reaching performance (question 1) appears to be more attenuated than the training effect of the Myomo orthosis (question 2).All 6 participants demonstrated improvements in movement efficiency for one or more of three reaching targets. Five of the 6 participants demonstrated improvements in one or more of the spatial characteristics of kinematic performance. Effect size calculations suggest that the magnitude of the training effect was greatest for movement efficiency and angular displacement (medium effect size) and the least for movement error and acceleration cycles (small effect size).