Functional magnetic resonance imaging (fMRI) provides a method for analyzing physiological roles of the sensorimotor cortex (SMC) and supplementary motor area (SMA) during voluntary movement. Although there are many reports on this theme, bimanual movement has rarely been studied. We investigated the activation of SMC and SMA during bimanual agonistic and antagonistic hand motions. Fourteen right-handed normal volunteers (mean age, 24.9yr) performed three kinds of motor tasks which required the repetitive making and opening of a fist: unilateral movement of the left hand (task A), simultaneous agonistic movement of both hands (task B, repeatedly making fists of both hands simultaneously then opening them simultaneously), simultaneous antagonistic movements of both hands (task C, making a fist and simultaneously opening the contralateral fist, and the reverse). Each task consisted of multiple periods of 20 sec of rest (resting period) alternating with periods of 20 sec motor execution (activation period). A task consisted of eight repetitions of this rest-activation cycle. Three slices of axial fMRI were obtained by the gradient-echo and echo-planar (1.5T) methods using the following parameters: echo time (TE)=50ms, repetition time (RT)=1, 000ms, slice thickness=7mm, field of view (FOV)=220×220mm, matrix=91×128, flip angle=75°. Totally, 255 functional images (85 images per slice) were obtained for each task. Cross-correlation with the time domain was used to detect significantly activated pixels. SMA was activated most in task C. There was no marked difference between task A and task B, evidence of the significant role of SMA in motor control during antagonistic hand movement (task C). Activation at the ipsilateral SMC during left hand motion (task A) occurred in only 3 of the 14 subjects. A comparison of SMC activities showed that the least activation occurred during task B. SMC activity is reported to be affected by the complexity of unilateral hand movement. Our findings support this in terms of bimanual motion and suggest that bimanual agonistic movement (at least in the making and opening of a fist) is simpler and more automatic than either bimanual antagonistic movement or unilateral hand movement.

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we studied the sympathetic skin response (SSR) on the hand, evoked by magnetic stimulation of the neck, in fifty-two hemiplegic patients (26 men and 26 women) caused by cerebro vascular accident. Twenty-five of the 52 patients had hemiparesis on the right side of the body and twenty-four of them had hemiparesis on the left side. All tests were performed with the patients relaxed and sitting in a warm, quiet room. The center of the circular coil was placed over the 7th cervical spinous process. Magnetic stimulation was given at a 50% intensity of the magnetic stimulator (Magstim 200). Counter-clockwise current flow in the coil was used for the responses in the right hand. Stimulations were repeated six times, with intervals of at least 30 sec, on each side The SSRs were amplified and recorded with a restricted filter setting of 0.5Hz to 3kHz using the Viking apparatus. The amplitudes of the waves were measured from peak to peak The SSR was elicited in forty-six of the 52 patients. The habituation was observed, but was not marked. There were strong correlations between the shortest latency and the mean latency, and between the largest amplitude and the mean amplitude. The amplitude of the SSRs in the hemiplegic side of the patients were significantly reduced compared to those in the sound side. In comparison the amplitudes were reduced in the elderly patients (over 60 years old) compared to the younger patients, and also in patients in the subacute phase (within 3 months) compared to those in the late phase. The amplitudes were diminished and the latencies were prolonged in the patients with larger lesions (over 3cm across) compared to those with smaller lesions. The SSR, evoked by magnetic stimulation is a useful and simple method in evaluating the autonomic function. The central pathway of the SSR is uncertain. The medullary reticular formation and midbrain are emphasized as the center of the SSR, In the present study, we have demonstrated abnormal SSRs in the stroke patients, that may reflect suppression of the somato-sympathetic reflex caused by damage of the brain.

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The shoulder contracture is one of the main problems in the field of stroke rehabilitation. Hyper activity of the subscaplaris muscle might interfere with flexion shoulder movement in the hemiplegic shoulder. Eleven patients with spastic hemiplegia, limited range of motion and painful shoulders, underwent percutaneous phenol blocks to the motor points on the subscapuralis muscle. Patient's ages ranged from 44 to 65 years old (mean: 56.8 years old) and duration of hemiplegia ranged from 2 to 12 months (mean: 3.9 months). Immediate and significant improvements in passive range of motion were observed in flexion (25.6°), abduction (18.9°), and external rotation (23.9°) after motor point block (p<0.01: Wilcoxon signed-rank test). Relief of shoulder pain was also recognized in the six patients. The active range of motion of shoulder improved significant among the three patients in the shoulder flexion and abduction (10° to 50°). This result suggested that the subscapularis motor point block could improve not only shoulder pain but also active shoulder movement. It could be a potentially useful technique for hemiplegic patients with shoulder pain and poor active shoulder movement to improve their ADL. The improvement of active shoulder movement with the subscapularis motor point block might be limited to mildly affected stroke patients, though it could be generally effective in improving the passive range of motion in the hemiplegic shoulder.

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