Neuromodulation in Drug Resistant Epilepsy

Abstract

Epilepsy affects approximately 70 million people worldwide, and it is a significant contributor to the global burden of neurological disorders. Despite the advent of new AEDs, drug resistant-epilepsy continues to affect 30-40% of PWE. Once identified as having drug-resistant epilepsy, these patients should be referred to a comprehensive epilepsy center for evaluation to establish if they are candidates for potential curative surgeries. Unfortunately, a large proportion of patients with drug-resistant epilepsy are poor surgical candidates due to a seizure focus located in eloquent cortex, multifocal epilepsy or inability to identify the zone of ictal onset. An alternative treatment modality for these patients is neuromodulation. Here we present the evidence, indications and safety considerations for the neuromodulation therapies in vagal nerve stimulation (VNS), responsive neurostimulation (RNS), or deep brain stimulation (DBS).

Keywords: DBS; RNS; VNS; drug-resistant epilepsy; epilepsy; neuromodulation; neurostimulation.

Figure 1.

Responsive Neurostimulator (RNS). The top left images show the neurostimulator; bottom image shows the neurostimulator with attached leads; top right image shows an illustration of the device placed in the skull.

Figure 2.

Deep Brain Stimulator (DBS). The left images show the stimulator attached to the left pectoral region; the right image shows the stimulator without leads attached.

Figure 3.

Vagus Nerve Stimulator (VNS). Stimulator implanted subcutaneously in the left anterior chest wall with stimulating electrodes coiled around the left vagus nerve.