Repetitive transcranial magnetic stimulation of contralesional primary motor cortex improves hand function after stroke.
OBJECTIVE
A recent report has demonstrated that the contralesional primary motor cortex (M1) inhibited the ipsilesional M1 via an abnormal transcallosal inhibition (TCI) in stroke patients. We studied whether a decreased excitability of the contralesional M1 induced by 1 Hz repetitive transcranial magnetic stimulation (rTMS) caused an improved motor performance of the affected hand in stroke patients by releasing the TCI.


METHODS
We conducted a double-blind study of real versus sham rTMS in stroke patients. After patients had well- performed motor training to minimize the possibility of motor training during the motor measurement, they were randomly assigned to receive a subthreshold rTMS at the contralesional M1 (1 Hz, 25 minutes) or sham stimulation.


RESULTS
When compared with sham stimulation, rTMS reduced the amplitude of motor-evoked potentials in contralesional M1 and the TCI duration, and rTMS immediately induced an improvement in pinch acceleration of the affected hand, although a plateau in motor performance had been reached by the previous motor training. This improvement in motor function after rTMS was significantly correlated with a reduced TCI duration.


CONCLUSIONS
We have demonstrated that a disruption of the TCI by the contralesional M1 virtual lesion caused a paradoxical functional facilitation of the affected hand in stroke patients; this suggests a new neurorehabilitative strategy for stroke patients.
Takeuchi
Naoyuki
N
Department of Rehabilitation Medicine, Hokkaido University Graduate School of Medicine, Sapporo 060-0814, Japan. naoyuki@med.hokudai.ac.jp
Chuma
Takayo
T
Matsuo
Yuichiro
Y
Watanabe
Ichiro
I
Ikoma
Katsunori
K
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D003337:Corpus Callosum / Q000503:physiopathology; D004311:Double-Blind Method; D005260:Female; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009048:Motor Skills; D020127:Recovery of Function; D020521:Stroke / Q000503:physiopathology*; D000071939:Stroke Rehabilitation; D013647:Task Performance and Analysis; D050781:Transcranial Magnetic Stimulation / Q000379:methods*