Neuromodulation for Epilepsy

Epilepsy surgery encompasses a wide range of procedures aimed at reducing or eliminating seizures. In these procedures, there are opportunities to employ intraoperative neurophysiology to map the epileptic focus and accurately identify functional areas of the brain. In cases of drug-resistant epilepsy where onset is diffuse, multifocal, or in an eloquent region of the brain, resection is not possible, and neuromodulation can be considered to reduce the seizure burden. While resective or ablative therapy aims to be curative, neuromodulation techniques for epilepsy are generally considered palliative. The goal of neuromodulation is to use an implantable device with electrodes and a pulse generator to use electrical energy to interfere with the nervous system. Three neuromodulation modalities have been approved by the United States FDA for epilepsy: vagus nerve stimulation, deep brain stimulation of the anterior nucleus of the thalamus, and responsive neurostimulation. While rates of seizure freedom with neuromodulation are lower than with resection of an epileptogenic focus, many patients experience >50% reduction in seizures, and results improve with time, suggesting both acute and chronic benefits with these therapies.