Electrical Stimulation of the Hippocampal Epileptic Foci for Seizure Control: A Double‐Blind, Long‐Term Follow‐Up Study

Abstract

Summary: Purpose: Our aim was to evaluate the safety and efficacy of electrical stimulation of the hippocampus in a long‐term follow‐up study, as well as its impact on memory performance in the treatment of patients with refractory mesial temporal lobe epilepsy. Methods: Nine patients were included. All had refractory partial complex seizures, some with secondary generalizations. All patients had a 3‐month‐baseline‐seizure count, after which they underwent bilateral hippocampal diagnostic electrode implantation to establish focus laterality and location. Three patients had bilateral, and six, unilateral foci. Diagnostic electrodes were explanted and definitive Medtronic electrodes were implanted directed into the hippocampal foci. Position was confirmed with MRI and afterwards, the deep brain stimulation system internalized. Patients signed the informed consent approved by the Hospital's Ethics Committee and began a double‐blind stimulation protocol. Patients attended a medical appointment every 3 months for seizure diary collection, deep brain stimulation system checkup, and neuropsychological testing. Results: Follow‐up ranged from 18 months to 7 years. Patients were divided in two groups: five had normal MRIs and seizure reduction of >95%, while four had hippocampal sclerosis and seizure reduction of 50–70%. No patient had neuropsychological deterioration, nor did any patient show side effects. Three patients were explanted after 2 years due to skin erosion in the trajectory of the system. Conclusions: Electrical stimulation of the hippocampus provides a nonlesional method that improves seizure outcome without memory deterioration in patients with hippocampal epileptic foci.

A network approach for modulating memory processes via direct and indirect brain stimulation: Toward a causal approach for the neural basis of memory

“…In contrast, cDES studies typically report no effect of hippocampal stimulation on memory although this is likely explained by the fact that stimulation does not occur specifically during encoding (Boëx et al, 2011;McLachlan, Pigott, Tellez-Zenteno, Wiebe, & Parrent, 2010;Miatton et al, 2011;Velasco et al, 2007). In these studies, high frequency (130 -450Hz) direct electrical stimulation was delivered chronically (3 to 18 months) to the hippocampal region, and patients were tested using standardized memory tasks in the baseline state (before stimulation or with stimulation off for a matched period of time) vs. after chronic stimulation.…”

Invazív neuromoduláció a gyógyszerrezisztens epilepsziák kezelésében

“…Az 1. táblázat azokat a célpontokat foglalja össze, amelyek antiepilepsziás célzattal stimulációra kerültek [11,12,13,14,15,16,17,18,19,20].…”

Possible new avenues in epilepsy treatment: the stimulation techniques deep brain stimulation, vagal nerve stimulation, transcranial magnetic stimulation

“…1) has so far been applied in 22 patients with temporal lobe epilepsy [39][40][41], with overall positive clinical results. Out of these 22 patients, 5 became seizure-free, 10 patients showed a reduction of seizure frequency of at least 50%, 6 patients had a reduction of less than 50% and one patient experienced an increase of seizure frequency.…”