Kyozo Yonemoto

Evaluation and treatment of shoulder subluxation in hemiplegia : Relationship between subluxation and pain

Shoulder subluxation in hemiplegic patients has been recognized as a difficult problem to manage. In the study contained herein, our aims are to evaluate shoulder subluxation, to clarify if shoulder subluxation causes pain, and to discuss the treatment of shoulder subluxation. The study included 75 hemiplegic patients with shoulder subluxation. Each patient was evaluated for the degree of shoulder pain, motor recovery of the upper limb, and shoulder range of motion. Some indexes for evaluating subluxation were measured with radiographs of the shoulders. Arthrograms of the affected shoulder joint were taken in 23 patients. The following results were found: (1) shoulder pain was significant more frequently in left hemiplegia; (2) vertical disparity was strongly correlated with discrepancy of the descendant ratio; (3) severe inferior subluxation had a tendency to show medial displacement of the humeral head; (4) there were correlations between shoulder pain and shoulder range of motion, especially external rotation; (5) adhesive changes in the arthrograms were seen in most subjects. These results indicate that there is no relation between shoulder subluxation and pain, and adhesive capsulitis is a main cause of shoulder pain. We conclude that correct positioning and shoulder range of motion exercises are advisable in hemiplegic patients with shoulder subluxation.

Language-related brain function during word repetition in post-stroke aphasics

We compared fMRI findings (using SPM99) obtained with repetition task in normal subjects with those of two patients with Brocas and Wernickes aphasia who received speech therapy and showed complete recovery. Both aphasic patients with left hemisphere damage who showed complete recovery exhibited activation of only the compensatory area in the right hemisphere during the repetition task. Recovery from Brocas aphasia involves reorganization and neuromodulation between the external temporopolar area and the anterior superior temporal area of the superior temporal gyrus, putamen and the inferior frontal gyrus, while that from Wernickes aphasia involves reorganization and neuromodulation between the superior temporal gyrus of the temporal region, the posterior supramarginal gyrus and inferior parietal lobule of the parietal region.

Influence of isoflurane concentration and hypoxia on functional magnetic resonance imaging for the detection of bicuculline-induced neuronal activation.

Our present study shows that transient changes in relative cerebral blood volume (rCBV) induced by stimulation with bicuculline under six different conditions of anesthesia can be detected with high spatial resolution functional magnetic resonance imaging (fMRI). Bicuculline was administered at a low dose to induce neural activation, and no seizure activity was noted. Of the six conditions, the maximal reaction to bicuculline was observed under 1.5% isoflurane in 60% nitrogen and 40% oxygen. Our results imply that the rCBV changes under this level of isoflurane anesthesia with body temperature maintained at 37.5°C are probably suitable for further fMRI studies.

Behavioural recovery correlated with MRI in a rat experimental stroke model

Primary objective : To characterize a necrotic lesion using MRI and motor recovery using behavioural methods. Research design : Stroke model based on two steps: (1) development of a lesion using MR-imaging parameters and (2) behavioural recovery. Methods and procedures : Seventy male Sprague-Dawley rats were used. A focal lesion of the right sensorimotor cortex was induced photochemically. Main outcomes and results : The maximum volume of oedema and the lesion damage was reached by ¨ 6 hours. In the lesion area, the apparent diffusion coefficient (ADC) increased from 6 hours, then decreased from 24 hours. All animals spontaneously recovered motor function by day 10, despite the continued presence of the cortical lesion. Conclusions : The results show that this model mimics a core lesion, as well as the late phase in a human stroke episode. This model might be used for longitudinal study of the basic mechanisms of motor recovery.