Seizure outcome after hippocampal deep brain stimulation in a prospective cohort of patients with refractory temporal lobe epilepsy

Purpose: In this study, we present the results obtained from a series of patients with refractory temporal lobe epilepsy (r-TLE) who underwent hippocampal deep brain stimulation (Hip-DBS). Methods: Nine consecutive adult patients were studied. Low-frequency and high-frequency stimulation was carried out immediately after the insertion of each electrode. Chronic continuous high-frequency stimulation was used during treatment. The mean follow-up time was 30.1 months. The mean age of the patients was 37.2 years. The MRI scan was normal in three patients; four patients had bilateral mesial temporal sclerosis (MTS), and two had unilateral MTS. Results: The patients with unilateral MTS received unilateral implantation and experienced a 76% and an 80% reduction in seizure frequency after Hip-DBS. All patients with normal MRI scans were implanted bilaterally. Two of these patients received unilateral activation of the electrodes and experienced a 97% and an 80% reduction in seizure frequency; the third patient had bilateral activation of the device and was a non-responder. All patients with bilateral MTS were implanted bilaterally. Three of these patients received unilateral activation of the device and experienced a 66%, a 66% and a 100% reduction in seizure frequency after Hip-DBS; one patient had bilateral electrode activation, and was a non-responder. Whenever present, generalised tonic-clonic seizures disappeared completely after Hip-DBS. Conclusions: Although performed on a relatively small number of patients, Hip-DBS was safe and effective in our patients with r-TLE. Seven of the nine patients were considered responders. Hip-DBS might represent a useful therapeutic option in patients with refractory temporal lobe epilepsy who were not candidates for resective surgery or have had previous failed procedures. (C) 2013 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.