Tailoring brain stimulation to the nature of rehabilitative therapies in stroke- a conceptual framework based on their unique mechanisms of recovery

摘要

Over the past decade there has been growing interest in combining non-invasive brain stimulation (NIBS) with unilateral therapies involving the paretic upper-limb in order to accelerate rehabilitative outcomes in stroke. However, despite showing early promise, several recent clinical trials of non-invasive brain stimulation have failed to augment rehabilitative outcomes of the paretic upper-limb. Instead, the benefits of NIBS+therapy are modest, and vary considerably from patient-to-patient, failing especially in patients with greater upper-limb impairments. Given these inconsistent results, the present review attempts to address why pairing NIBS with unilateral approaches is weakly generalizable to patients in all ranges of impairments; specifically, do the mechanisms of unilateral therapies fail across the severely impaired? Further, this review addresses whether alternate therapies, such as bilateral therapies involving both upper-limbs, are better suited for the more impaired patients, where they may be more feasible and offer neurophysiologic advantages not offered with unilateral therapies. By comparing the potential neurophysiological mechanisms underlying unilateral and bilateral therapies, this review concludes by providing insight as to how to create NIBS paradigms that are tailored to distinctly augment the effects of therapies across patients with varying degrees of impairment.