Differential effects of high-frequency repetitive transcranial magnetic stimulation over ipsilesional primary motor cortex in cortical and subcortical middle cerebral artery stroke.
OBJECTIVE
Facilitation of cortical excitability of the ipsilesional primary motor cortex (M1) may improve dexterity of the affected hand after stroke. The effects of 10 Hz repetitive transcranial magnetic stimulation (rTMS) over ipsilesional M1 on movement kinematics and neural activity were examined in patients with subcortical or cortical stroke.


METHODS
Twenty-nine patients with impaired dexterity after stroke (16 subcortical middle cerebral artery [MCA] strokes, 13 MCA strokes involving subcortical tissue and primary or secondary cortical sensorimotor areas) received 1 session of 10 Hz rTMS (5-second stimulation, 25-second break, 1,000 pulses, 80% of the resting motor threshold) applied over: 1) ipsilesional M1 and 2) vertex (control stimulation). For behavioral testing, 29 patients performed index finger and hand tapping movements with the affected and unaffected hand prior to and following each rTMS application. For functional magnetic resonance imaging, 18 patients performed index finger tapping movements with the affected and unaffected hand before and after each rTMS application.


RESULTS
Ten-Hz rTMS over ipsilesional M1, but not over vertex, improved movement kinematics in 14 of 16 patients with subcortical stroke, but not in patients with additional cortical stroke. Ten-Hz rTMS slightly deteriorated dexterity of the affected hand in 7 of 13 cortical stroke patients. At a neural level, rTMS over ipsilesional M1 reduced neural activity of the contralesional M1 in 11 patients with subcortical stroke, but caused a widespread bilateral recruitment of primary and secondary motor areas in 7 patients with cortical stroke. Activity in ipsilesional M1 at baseline correlated with improvement of index finger tapping frequency induced by rTMS.


CONCLUSIONS
The beneficial effects of 10 Hz rTMS over ipsilesional M1 on motor function of the affected hand depend on the extension of MCA stroke. Neural activity in ipsilesional M1 may serve as a surrogate marker for the effectiveness of facilitatory rTMS.
Ameli
Mitra
M
Department of Neurology, University Hospital Cologne, Cologne, Germany.
Grefkes
Christian
C
Kemper
Friederike
F
Riegg
Florian P
FP
Rehme
Anne K
AK
Karbe
Hans
H
Fink
Gereon R
GR
Nowak
Dennis A
DA
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena / Q000502:physiology; D002540:Cerebral Cortex / Q000503:physiopathology; D019054:Evoked Potentials, Motor; D005260:Female; D005385:Fingers / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000503:physiopathology; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000503:physiopathology / Q000534:rehabilitation*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009048:Motor Skills / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D016896:Treatment Outcome