Effects of low-frequency repetitive transcranial magnetic stimulation of the contralesional primary motor cortex on movement kinematics and neural activity in subcortical stroke.
BACKGROUND
Following the concept of interhemispheric competition, downregulation of the contralesional primary motor cortex (M1) may improve the dexterity of the affected hand after stroke.


OBJECTIVE
To determine the effects of 1-Hz repetitive transcranial magnetic stimulation (rTMS) of the contralesional M1 on movement kinematics and neural activation within the motor system in the subacute phase after subcortical stroke.


METHODS
Crossover investigation.


METHODS
A university hospital.


METHODS
Fifteen right-handed patients with impaired dexterity due to subcortical middle cerebral artery stroke received 1-Hz rTMS for 10 minutes applied to the vertex (control stimulation) and contralesional M1. For behavioral testing, patients performed finger and grasp movements with both hands at 2 baseline conditions, separated by 1 week, and following each rTMS application. For functional magnetic resonance imaging, patients performed hand grip movements with their affected or unaffected hand before and after each rTMS application.


RESULTS
Application of rTMS to the contralesional M1 improved the kinematics of finger and grasp movements in the affected hand. At the neural level, rTMS applied to the contralesional M1 reduced overactivity in the contralesional primary and nonprimary motor areas. There was no significant correlation between the rTMS-induced reduction in blood oxygen level-dependent responses within the contralesional M1 and the degree of behavioral improvement of the affected hand. Overactivity of the contralesional dorsal premotor cortex, contralesional parietal operculum, and ipsilesional mesial frontal cortex at baseline predicted improvement of movement kinematics with the affected hand after rTMS of the contralesional M1.


CONCLUSIONS
The functional magnetic resonance imaging data suggest that rTMS of the contralesional M1 may normalize neural activation within the cortical motor network after subcortical stroke. Identifying patients suitable for rTMS intervention based on individual patterns of cortical activation may help to implement rTMS in motor rehabilitation after stroke.
Nowak
Dennis A
DA
Department of Neurology, University Hospital Cologne, University of Cologne, Kerpener Strasse 62, D-50924 Cologne, Germany. dennis.nowak@uk-koeln.de
Grefkes
Christian
C
Dafotakis
Manuel
M
Eickhoff
Simon
S
Küst
Jutta
J
Karbe
Hans
H
Fink
Gereon R
GR
D000328:Adult; D001696:Biomechanical Phenomena / Q000379:methods; D018592:Cross-Over Studies; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology*; D009474:Neurons / Q000473:pathology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D020521:Stroke / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*