Cortical activation pattern of compensatory movement in stroke patients

Objective: Little is known about the cortical activation pattern of compensatory movement (CM) in stroke patients. We attempted to investigate the cortical activation pattern of compensatory movement in stroke patients, using functional MRI (fMRI). Methods: Eight hemiparetic stroke patients were recruited for this study. We measured the shoulder abduction angle when each subject was simulating eating in a sitting position, which was considered as the degree of CM. The fMRI was performed at 1.5T using an elbow motor task at a frequency of 0.5 Hz. Results: There was an inverse correlation between the shoulder abduction angle of the affected side and the LI (Laterality Index) (r = -0.745; p < 0.05). The shoulder abduction angle of the affected side was significantly related to the sum of activated voxels in all regions of interest (r = 0.776; p < 0.05) and the activated voxels of the supplementary motor area (r = 951; p < 0.05). However, we did not find any correlation between the shoulder abduction angle and the activated voxels of other brain areas. Conclusions: We demonstrated that a greater shoulder abduction angle on the affected side requires more cortical activation. Therefore, CM appears to be related to the change of the cortical motor control toward greater recruitment of cortical neurons.