Noninvasive Brain Stimulation in Epilepsy

Neurostimulation in epilepsy is a long standing established concept, and through experimental and clinical uses, our understanding of neurostimulation and neuromodulation has grown substantially. Noninvasive brain stimulation techniques use electromagnetic principles to noninvasively modulate brain activity in a spatiotemporally targeted manner. This review focused on the two predominant forms of noninvasive neurostimulation: transcranial magnetic stimulation (TMS) and transcranial direct current stimulation, and their current applications in the diagnosis and management of epilepsy. A number of small randomized sham-controlled studies suggest that both TMS and transcranial direct current stimulation may have a beneficial effect in decreasing seizure frequency in patients with medically refractory epilepsy, without significant side effects. Small pilot studies also suggest that TMS in combination with EEG may be used to develop quantitative biomarkers of cortical hyperexcitability in patients with epilepsy. Furthermore, TMS is already Food and Drug Administration-cleared for presurgical mapping of eloquent cortex, and preliminary studies suggest that navigated TMS represents a highly valuable clinical supplement for preoperative functional planning. Transcranial magnetic stimulation and transcranial direct current stimulation have shown great potential benefit for patients with epilepsy; however, further large multicenter randomized sham-controlled studies are needed to better optimize stimulation settings and protocols, define mechanisms of action, assess long-term effects, and clearly define roles and determine efficacy.