Abstracts

Rationale: Recent studies have shown that Deep Brain Stimulation (DBS) can efficiently suppress spontaneous seizures originating from the medial temporal lobe. Despite these promising results, the optimal stimulation target remains undetermined. In this animal experimental study, we evaluated whether DBS targeted to the ventral hippocampal commissure (VHC) suppresses spontaneous seizure activity in the kainic acid rat modelMethods: Status epilepticus was elicited by intraperitoneal injection of KA (5mg/kg/h according to Hellier et al.). Two months after SE, spontaneous seizures could be observed, and rats were implanted with VHC DBS and hippocampal depth electroencephalography (EEG) electrodes. After 15 days of baseline EEG monitoring, rats (n=9) were treated for 10 days with Poisson distributed stimulation (PDS) at 130 Hz in the VHC. Stimulation intensity was fixed at 100 A. This stimulation period was followed by a wash-out period of 15 daysResults: Overall VHC-DBS caused a significant reduction of seizure frequency of 46% compared to baseline. Four out of 9 rats (44%) were classified as responders based on a seizure reduction of more than 50% in response to VHC-DBS.. In the responder group, mean seizure frequency during VHC-PDS was decreased with 66% (p<0,05) compared to the baseline value. In the non-responder group, 3 rats had a seizure reduction between 30% and 50%, 2 rats had no reduction in seizure frequency. During an outlasting period of 15 days, mean seizure frequency of all rats was decreased 26% (p<0,05) compared to the baseline value. In the responder group, mean seizure frequency was 58% (p<0,05) lower during the outlasting period than during baseline.Conclusions: Continuous treatment with PDS during 10 days in VHC significantly reduces seizure frequency in the kainic acid rat model. In the responder group, the seizure suppressive effect outlasts the period of VHC-PDS with at least 15 days. Temporary treatment with VHC-PDS may induce a long-lasting therapeutic effect.