ABSTRACT
The aim of this study was to evaluate and compare the reorganization of corticospinal pathways innervating upper extremity muscles in patients with spastic hemiplegic cerebral palsy (CP). Thirty-2 patients (17 male, 15 female) with spastic hemiplegic CP were enrolled. The average age (mean ± standard deviation) was 7.5 ± 4.6 (range: 2–17) years. Transcranial magnetic stimulation (TMS) was applied to the unaffected and affected motor cortices in turn, and bilateral electromyographic recordings were made from the first dorsal interossei (FDI), the biceps brachii (BB), and the deltoid muscles during rest. The onset latency, central motor conduction time, and peak-to-peak amplitude of motor evoked potentials (MEPs) were measured for each muscle bilaterally. Whilst TMS of both affected and unaffected hemispheres elicited contralateral MEPs in all muscles, the number of MEPs evoked from the affected hemisphere was less than from the unaffected hemisphere for FDI and BB. TMS responses to stimulation of the affected side showed prolonged latency and reduced amplitude. The amplitudes of MEPs increased with age whereas the latencies were relatively constant. These results suggest that the corticospinal pathways to the proximal and distal muscles of the upper extremity undergo sequential maturation and reorganization patterns.
Subject(s)
Child , Humans , Male , Cerebral Palsy , Deltoid Muscle , Evoked Potentials, Motor , Muscle Spasticity , Muscles , Pyramidal Tracts , Transcranial Magnetic Stimulation , Upper ExtremityABSTRACT
Ohjective To explore the impact of constraint-induced aphasia therapy (CIAT) on language function and neural activity in patients with chronic Broca's aphasia.Methods Two chronic aphasics whose use of language was recovering after standard language therapy were selected to receive 1.5 h of CIAT twice daily for two weeks (30 hours in total).Before and after the CIAT they were tested using a block-designed picture-naming task,fMRIs were taken and their use of language was examined.Results The language function assessments showed relatively large improvements in the subjects' use of language after 4 weeks of conventional language training,but not much further change after 8 and 12 weeks.After the two weeks of CIAT,their language function improved further to a certain extent.fMRI showed increased activation in the left inferior frontal gyrus with or without enhanced activation in the left hemisphere,and reduced activation in the right inferior frontal gyrus.Conclusions Functional reorganization induced in the brain by CIAT was associated with up-regulation of the left inferior frontal gyrus or down-regulation of the right inferior frontal gyrus.Even the whole language network may have been modified.
ABSTRACT
Objective To explore the pattern of functional reorganization in the cortex after corticospinal tract ( CST) injury and its relationship with the recovery of upper limb motor function. Methods Fifteen patients with complete paralysis on one side after acute cerebral infarction were studied. Within 1 week after the onset, func-tional magnetic resonance imaging ( fMRI ) and diffusion tensor tractography ( DTT) were performed in parallel with timed finger flexion and extension movements in all subjects. The number of nerve fibers in corticospinal tract ( CST) in the affected and healthy sides was measured by using Dtv.Ⅱ. R2 software. One and three months later, fMRI was performed while the affected fingers were flexed and extended passively and any cortical activation was observed. In addition, Fugl-Meyer arm motor function scores were assessed one week, one month and three months after the stroke. Results According to the reconstructed nerve fiber number in CST on the affected side, the patients were classified into three types. Type I:the number of newly-built CST nerve fibers is more than 2/3 of that on the healthy side;type II:the ratio is between 1/3 and 2/3;and type III:the ratio is less than 1/3. For typeⅠpatients, blood oxygenation level-dependent fMRI ( bold-fMRI) showed initial activation of the bilateral sensorimotor cortex ( SMC) and the sup-plementary motor area ( SMA) on the affected side. That was followed by a gradual decrease in the activity in the healthy SMC and an increase in the affected SMC at 1 and 3 months. Among the type II patients bold-fMRI indicated activation of the SMC and SMA on the affected side initially, significant activation of the bilateral SMC and SMA one month later and then stronger activation in the SMC on the healthy side and a weakening of activation in the SMC on the affected side. For typeⅢpatients, initially the SMA and the posterior parietal cortex were found to be slightly ac-tivated. One month later SM1 on the unaffected side was slightly activated, and 3 months later neither the SMC nor the SMA on either side was activated. One week after the onset, the average upper extremity FM scores of the three types of subjects were not significantly different. After one month the three groups′averages were all significantly dif-ferent from one another. But after three months the averages for types I and II were again not significantly different, but significantly better than the average of the type III patients. Conclusion Different CST injuries induce different modes of cortical reorganization. The reorganization is a dynamic process, and different activation patterns are closely correlated with clinical prognosis.