Transcranial Magnetic Stimulation: Its Current Role in the Evaluation of Patients Post‐Stroke

Transcranial magnetic stimulation (TMS) is a noninvasive and painless technique used to stimulate the human motor cortex. The resulting motor evoked potential (MEP) can be recorded from a target muscle with conventional electromyography. Preservation of the MEP in the first hours after stroke predicts a favorable outcome, whereas absence of the MEP predicts poor outcome. Many stroke patients, in particular those with motor neglect, show a lengthening of the TMS evoked silent period, indicating enhanced cortical inhibition. TMS mapping provides evidence that motor representations in the affected motor cortex expand and shift during motor recovery. These various TMS applications improve outcome prediction and enhance our understanding of the mechanisms underlying reorganization after stroke. Complementary to the clinical examination, TMS may be used soon to monitor and guide rehabilitative strategies in stroke patients.