We aimed to determine if there is a reduction in the antiepileptic drugs (AEDs) burden after deep brain stimulation (DBS) therapy for drug-resistant epilepsy (DRE) and evaluate its association with seizure outcomes.

AEDs reduction postoperatively is a measure of success in epilepsy surgery. DBS reduces seizure burden in some patients with DRE, but its effect on the use of AEDs postoperatively has not been previously investigated.

We performed a retrospective review of patients who underwent DBS implantation between January 2006 and September 2020 at our center with >1 year of stimulation therapy. We analyzed the median percentage reduction in disabling clinical seizures, the responder rate (>50% reduction in disabling seizures), and their association with changes in the number of AEDs postoperatively. 

Eighteen patients (50% female) were included in our study with a median age at implantation of 32 years. Their median DRE duration was 19 years and their median pre-operative seizure frequency was 12/month, despite an average of 3 AEDs. 8/18 (44%) were radiologically non-lesional and 10/18 (56%) were electrophysiologically multifocal. 11/18 (61%) underwent bilateral implantation of the anterior nucleus of the thalamus (ANT) and 7/18 (39%) implantation of the centromedian (CM) nucleus. The median seizure frequency reduction was 76% and the responder rate was 83%. 1/18 (6%) patients exhibited seizure freedom. The median number of AEDs post-implantation was 3. Compared to pre-implantation, 16/18 (89%) of the patients had no change in the total number of AEDs and 2/18 (11%) underwent AEDs reduction. There was no statistically significant association between the seizure outcome and change in the number of AEDs.  

Our study confirms the utility of DBS for patients with DRE who failed or are not good candidates for destructive surgery. However, improvement in seizure frequency is not accompanied by a significant reduction in the number of post-operative AEDs.