Fasoli SE, Krebs HI, Stein J, Frontera WR, Hogan N. Effects of robotic therapy on motor impairment and recovery in chronic stroke. Arch Phys Med Rehabil 2003;84:477-82. Objective: To examine whether robotic therapy can reduce motor impairment and enhance recovery of the hemiparetic arm in persons with chronic stroke. Design: Pre-posttest design. Setting: Rehabilitation hospital, outpatient care. Participants: Volunteer sample of 20 persons diagnosed with a single, unilateral stroke within the past 1 to 5 years, with persistent hemiparesis. Interventions: Robotic therapy was provided 3 times weekly for 6 weeks. Subjects able to reach robot targets were randomly assigned to sensorimotor or progressive-resistive robotic therapy groups. Robotic therapy consisted of goal-directed, planar reaching tasks to exercise the hemiparetic shoulder and elbow. Main Outcome Measures: The Modified Ashworth Scale, Fugl-Meyer test of upper-extremity function, Motor Status Scale (MSS) score, and Medical Research Council motor power score. Results: Evaluations by a single blinded therapist revealed statistically significant gains from admission to discharge (P[lt].05) on the Fugl-Meyer test, MSS score, and motor power score. Secondary analyses revealed group differences: the progressive-resistive therapy group experienced nonspecific improvements on wrist and hand MSS scores that were not observed in the sensorimotor group. Conclusions: Robotic therapy may complement other treatment approaches by reducing motor impairment in persons with moderate to severe chronic impairments.