Motor Imagery Training Reduces Contralesional Compensation in Stroke Patients with Moderate to Severe Upper Limb Impairment

Motor imagery training (MIT) is an adjunctive approach for motor recovery after stroke. It has been suggested as a "backdoor" to motor system at all stages of stroke recovery, especially for patients with severe motor impairment. However, the current MIT-related brain reorganization evidences were obtained mainly from mild stroke patients, little is known about severe patients. In this study, we recruited 12 first-ever stroke patients with moderate to severe upper limb impairment and investigated their brain reorganization after MIT using task-state fMRI. During passive movement of the unaffected hand, the activation exhibited a normal contralateral-lateralized pattern. However, during passive movement of the affected hand, ipsilateral compensational activation was observed in the contralesional sensorimotor areas, and the compensational activation in the contralesional precentral gyrus was significantly decreased after MIT. Our study expanded the current understanding of neural mechanism of MIT to stroke patients with moderate to severe deficits.