Using motor imagery in the rehabilitation of hemiparesis

Objective: To examine the effectiveness of using motor imagery training in the rehabilitation of hemiparesis. Design: A before-after trial with clinical and behavioral analyses of single cases. Setting: Academic-affiliated rehabilitation hospital. Participants: Two survivors of embolic middle cerebral artery stroke that resulted in chronic hemiparesis. Intervention: A motor imagery training program consisting of imagined wrist movements (extension, pronation-supination) and mental simulations of reaching and object manipulation making use of a mirror box apparatus. Twelve 1-hour experimental sessions were delivered, 3 times a week for 4 consecutive weeks. Main Outcome Measures: Two clinical assessments, grip strength, 4 wrist functionality measurements, and 3 timed performance tests. All outcome measures were recorded before training began, at 3 times during the intervention month, with 2 additional long-term measurements. Results: Performance of the paretic limb improved after the imagery intervention, indicated by increases in assessment scores and functionality and decreases in movement times. The improvements over baseline performance remained stable over a 3-month period. Conclusions: These results demonstrate the potential for using motor imagery as a cognitive strategy for functional recovery from hemiparesis. The intervention targets the cognitive level of action processing while its effects may be realized in overt behavioral performance.