Reorganization of motor execution rather than preparation in poststroke hemiparesis.
OBJECTIVE
The aim of the present study was to examine movement-related potentials (MRPs) in patients in the "chronic" stage after cortical stroke with recovered hemiparesis compared with healthy control subjects.


METHODS
Right index finger MRPs were derived from 12 patients > or =1 year after infarction in the territory of the left middle cerebral artery as well as from 12 control subjects. MRP components were compared between groups.


RESULTS
In the patient group, the component directly preceding movement onset (negative slope [NS]) was significantly reduced over the lesioned hemisphere contralateral to the movement. Furthermore, increased motor potentials (MPs) were observed over the contralesional hemisphere during movement execution. No changes in the early MRP (Bereitschaftspotential) reflecting movement preparation were found.


CONCLUSIONS
Because the NS is supposed to be generated by the primary motor cortex, the decreased component over the lesioned hemisphere is interpreted to represent impaired contralateral M1 functioning in stroke patients. Contralesional activity has been reported as a probable sign of brain plasticity by functional imaging studies. Our results broaden these findings, giving new insights into the temporal course of movement-related brain activity in recovered cortical stroke patients. The data point to a functional reorganization of motor execution rather than preparation in poststroke hemiparesis.
Wiese
Holger
H
Department of Neurology, University of Duisburg-Essen, Hufelandstr. 55, 45122 Essen, Germany. holger.wiese@uni-essen.de
Stude
Philipp
P
Sarge
Robert
R
Nebel
Katharina
K
Diener
Hans-Christoph
HC
Keidel
Matthias
M
D000368:Aged; D000704:Analysis of Variance; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000473:pathology; D004569:Electroencephalography / Q000379:methods*; D019054:Evoked Potentials, Motor; D005385:Fingers; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000473:pathology; D009044:Motor Cortex / Q000473:pathology*; D009068:Movement; D009474:Neurons / Q000378:metabolism; D010291:Paresis / Q000209:etiology* / Q000503:physiopathology*; D011597:Psychomotor Performance; D020127:Recovery of Function; D020521:Stroke / Q000150:complications* / Q000628:therapy*; D013997:Time Factors