rTMS treatment in stroke rehabilitation
Stroke patients are often left with impairment of the upper limbs, even after intensive rehabilitation of upper limb function. The impairment of the upper limb is associated with disrupted activity within the brain's motor network. The disrupted activity is characterized by reduced activity in the affected motor cortex, which causes increased activity in the healthy motor cortex through increased interhemispheric inhibition. Recovery of motor function has been associated with normalization of the activity within the motor network.
Repetitive transcranial magnetic stimulation (rTMS) can be used to restore the disrupted activity, by normalizing the imbalance in activity between the two motor cortices. This can be done by inhibiting the increased activity in the healthy motor cortex, or by exciting the reduced activity in the affected motor cortex. A recent review by Lefaucheur et al. (2020) attributes level A evidence to inhibitory low frequency TMS of the healthy motor cortex in stroke patients during the subacute phase. This review also highlights the importance of performing TMS treatment in the subacute phase, which shows more promising results compared to the delivery of TMS treatment in the chronic phase.