Evolution of fMRI Activation in the Perilesional Primary Motor Cortex and Cerebellum With Rehabilitation Training-Related Motor Gains After Stroke: A Pilot Study

Abstract

Background. Previous studies report that motor recovery after partial destruction of the primary motor cortex (M1) may be associated with adaptive functional reorganization within spared M1. Objective. To test feasible methodologies for evaluating relationships between behavioral gains facilitated by rehabilitative training and functional adaptations in perilesional M1 and the cerebellum. Methods . Four patients with hemiparesis for more than 3 months after a cortical lesion partially within M1 and 12 healthy volunteers participated. Functional magnetic resonance imaging (fMRI) using a finger-tapping task and concurrent behavioral assessments, including the Fugl-Meyer Motor Assessment of the upper extremity and the Wolf Motor Function Test, were conducted before and after 2 weeks of arm-focused training; 2 patients were further examined 6 and 12 months later to evaluate long-term persistence of brain-behavior adaptations. Results. All patients showed higher activation magnitude in perilesional M1 than healthy controls before and after therapy. Further long-term functional gains paralleled the decrease of activation magnitude in perilesional M1 in the 2 more impaired cases. Conclusion. The evolution of suggestive correlations between serial scans of fMRI adaptive activity within the primary motor cortex and the cerebellum in relation to relevant behavioral changes over the course of 2 weeks of task-specific therapy and then no formal therapy suggests that repeated assessments may be best for monitoring therapy-induced neuroplasticity. This approach may help develop optimal rehabilitation strategies to maximize poststroke motor recovery as well as improve the search for brain-behavior correlations in functional neuroimaging research.