Opportunities for the future of transcranial magnetic stimulation and epilepsy

Drug-resistant epilepsy has traditionally been managed with medications or surgery aimed at removing or destroying epileptogenic tissue. In contrast, electrical brain stimulation seeks to alter dysfunctional neural circuits without tissue destruction. Transcranial magnetic stimulation (TMS) is a particularly attractive approach due to its favorable side-effect profile and robust diagnostic as well as therapeutic capacity. Cortical stimulation by TMS generates quantifiable evoked potentials that provide insights into seizure susceptibility and target engagement by therapeutics. Repetitive TMS (rTMS) has promise as a method for treating seizures, but essential questions remain as to which epilepsy syndromes and which cortical targets will respond to stimulation. Here, we speculate on questions pertaining to diagnostic and therapeutic TMS that may be answered in near-future studies. Will reliable measures to quantify seizure likelihood be available from measures of TMS-EMG or TMS-EEG evoked potentials? Might TMS help optimize other neuromodulation techniques? Can rTMS targeting superficial cortex, either in isolation or coupled with appropriately selected drugs, suppress generalized onset or multifocal seizures? Recent advances highlight the potential of bioelectronic medicine approaches such as TMS.