Abstracts

RATIONALE: Deep brain stimulation (DBS) is an emerging treatment for many functional neurological disorders. One potential application of DBS is for the treatment of intractable epilepsy. The inhibition of the subthalamic nucleus (STN) by high frequency stimulation (HFS) is believed to activate the nigral control of epilepsy system (NCES) leading to increased seizure threshold. Alternatively, STN stimulation may directly effect the cortex through the cortico-STN connection by means of antidromic inputs. We hypothesized that HFS of the STN has an anticonvulsant effect on kainic acid induced seizures in the rat.
METHODS: Six rats were implanted with bifrontal epidural electrodes and bilateral hippocampal electrodes. Additionally, concentric monopolar electrodes were implanted bilaterally in the STN with neurophysiological targeting. Subcutaneous injections of kainic acid (KA) (10mg/kg) were given to induce seizures acutely. The effect of HFS of the STN on the latency to first EEG seizure activity and the duration of focal and generalized EEG seizure activity were measured. Each animal served as its own control. The animals were sacrificed and histology was done to confirm the location of electrode.
RESULTS: There was no difference in total seizure duration between the group with STN stimulation and KA injection and the control with KA injection only. However, there was a significant difference between these groups in the duration of generalized seizures, with the STN stimulation group having a shorter duration of generalized seizure activity. There was no difference in the latency to EEG seizure between groups.
CONCLUSIONS: We therefore conclude that the main effect of HFS of the STN is to prevent secondary generalization
[Supported by: Medtronic]