Reorganization of sensory and motor systems in hemiplegic stroke patients - A positron emission tomography study

Background and Purpose-Cortical reorganization of motor systems has been fo und in recovered stroke patients. Reorganization in nonrecovered hemiplegic stroke patients early after stroke, however, is less well described. We us ed positron emission tomography to study the functional reorganization of m otor and sensory systems in hemiplegic stroke patients before motor recover y. Methods-Regional cerebral blood Row (rCBF) was measured in 6 hemiplegic str oke patients, with a single, subcortical infarct and 3 normal subjects with the [O-15]H2O injection technique. Brain activation was achieved by passiv e elbow movements driven by a torque motor. Increases of rCBF comparing pas sive movements and rest were assessed with statistical parametric mapping. Significant differences were defined at P<0.01. Results-In normal subjects, significant increases of rCBF were found in the contralateral sensorimotor cortex, supplementary motor area, cingulate cor tex, and bilaterally in the inferior parietal cortex. In stroke patients, s ignificant activation was observed bilaterally in the inferior parietal cor tex and in the contralateral sensorimotor cortex, ipsilateral prefrontal co rtex, supplementary motor area, and cingulate cortex. Significantly larger increases of rCBF in patients compared with normal subjects were found bila terally in the sensorimotor cortex, stronger in the ipsilateral, unaffected hemisphere, and in both parietal lobes, including the ipsilateral precuneu s. Conclusions-Passive movements in hemiplegic stroke patients before clinical recovery elicit some of the brain activation patterns that have been descr ibed during active movements after substantial motor recovery. Changes of c erebral activation in sensory and motor systems occur early after stroke an d may be a first step toward restoration of motor function after stroke.