Clinical characteristics and brain activation patterns of mirror movements in patients with corona radiata infarct.

OBJECTIVE: Mirror movements (MMs) are a phenomenon of involuntary movements that accompany physically intended movements of the opposite side of the body. In the current study, we investigated the clinical characteristics and cortical activation patterns of MMs in patients with corona radiata (CR) infarct, using functional MRI. SUBJECTS AND METHODS: We recruited 31 consecutive hemiparetic stroke patients with CR infarct. Functional MRI was performed to verify brain activation patterns during grasp-release movements of the affected hand, and MM of the unaffected hand was observed simultaneously. RESULTS: The prevalence of MMs was 54.8% (17 out of 31 patients), and the intensity of MMs ranged from mild to moderate. The severity of MM in the unaffected hand is closely related to the poor motor function of the affected upper extremity and to activations of the unaffected motor cortex and both supplementary motor areas (SMAs) during the movement of the affected hand. In addition, the activations of unaffected motor cortex and both SMAs were closely related to poor motor function of the affected upper extremity. CONCLUSIONS: The results suggest that MMs, poor motor function, and the activations of ipsilateral motor cortex and both SMAs are closely interconnected in patients with CR infarct.

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.