Different stimulation types will be administered in a crossover fashion, as follows. There will be four four-month periods of low-frequency DBS stimulation, and in each of these four-month periods, stimulation will occur at one of four different sites [the anterior nucleus of the thalamus (ANT), entorhinal cortex (ERC), piriform cortex (PiC), and hippocampal fornix (HCF)], with the order of receipt differing among study participants. There will be a 3-month washout period after each 4-month stimulation period, with the washout being standard of care (SOC) high-frequency DBS stimulation of the ANT. Finally, there will be a 7 to 12 month DBS stimulation period with the stimulation type that yielded the best results.
In this study, participants will receive unilateral Deep Brain Stimulation (DBS) for treatment of epilepsy, with network-based stimulation targets specifically defined using a stereo-electro-encephalographic evaluation and chronic recordings using the Medtronic Percept™ primary cell (PC) Neurostimulator DBS System with BrainSense™ Technology. The hypothesis is that, compared to no stimulation or to standard duty cycle high frequency stimulation, epilepsy neuromodulation using low frequency stimulation and informed by network architecture in patients with epilepsy that arises in a hippocampus that also subserves memory - epilepsy in a precious hippocampus (EPH) - will result in a significant decrease in seizure frequency and severity, paralleled by a decrease in EEG spike counts and improved memory function.