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Differential effects of high‐frequency repetitive transcranial magnetic stimulation over ipsilesional primary motor cortex in cortical and subcortical middle cerebral artery stroke
Author(s) -
Ameli Mitra,
Grefkes Christian,
Kemper Friederike,
Riegg Florian P.,
Rehme Anne K.,
Karbe Hans,
Fink Gereon R.,
Nowak Dennis A.
Publication year - 2009
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.21725
Subject(s) - transcranial magnetic stimulation , primary motor cortex , stroke (engine) , motor cortex , finger tapping , psychology , supplementary motor area , middle cerebral artery , medicine , physical medicine and rehabilitation , neuroscience , functional magnetic resonance imaging , stimulation , cardiology , audiology , ischemia , mechanical engineering , engineering
Objective Facilitation of cortical excitability of the ipsilesional primary motor cortex (M1) may improve dexterity of the affected hand after stroke. The effects of 10Hz 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 10Hz 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. Interpretation The beneficial effects of 10Hz 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. Ann Neurol 2009;66:298–309