Repetitive TMS will be performed bilaterally. The order of stimulation of the two hemispheres will be randomized. The stimulation of the two hemispheres will be performed sequentially at an interval of one minute. The motor cortex of each side will be stimulated for five consecutive days every month for twelve consecutive months. In the patients with absent first dorsal interosseous motor evoked potentials after stimulation of one hemisphere, the repetitive stimulation will be performed at the same intensity used for the opposite hemisphere.