PRIME: PReservIng Memory in Epilepsy

Inclusion Criteria: * Patients with a presumptive diagnosis of EPH determined by the group of clinicians who participate in patient management conference. * Ability to comply with test directions and provide informed consent or assent to the study, i.e. cognitively able to participate in studies \[typically intelligence quotient (IQ) of 65 or above\]. * Relatively preserved verbal memory - as determined via formal neuropsychological evaluation performed by the neuropsychologist. The values must within 1.5 standard deviation (SD) of the mean for verbal memory * Proficient in English, as all of our tasks and consent forms will be in English and the inclusion of non-English speakers will introduce another confound in this small sample size and preclude grouped analysis * Age 18 - 65 years (we expect the trial to take 5 years and wish to target patients with minimal medical co-morbidities) * Must have a minimum of 2 seizures of any type per month - this is essential to be able to detect the impact of neuromodulation on the epilepsy over relatively short intervals of time. Patients with secondary generalized seizures may also be enrolled so long as they have a maximum of 20 generalized seizures in the past 12 months (prior to enrollment), or an average of no more than 3 generalized seizures per month. Exclusion Criteria: * Impaired reading and cognitive functions (more than 3 standard deviations below the mean, usually an IQ \< 60), as determined by preoperative neuropsychologi…