Study of Direct Brain Recording and Stimulation for Memory Enhancement

Objective The primary objectives of this study are (1) to identify biomarkers of successful memory encoding and retrieval, and (2) to identify brain regions that can be stimulated to affect memory performance. The secondary objective is to identify biomarkers that can be used to predict cognitive impairment following resection surgery. Study Population One hundred (100) adult subjects with epilepsy who are enrolled in 11-N-0051 Epilepsy Surgery protocol. Study Design We plan to enroll individuals with drug resistant epilepsy who are enrolled in a separate protocol, 11-N-0051 Epilepsy Surgery, and who will undergo a neurosurgical procedure in which seizure activity and cognitive functions are mapped using intracranial electrodes in order to guide resection of seizure generating tissue. In this procedure, surgeons place electrodes solely based on clinical consideration with the goal of identifying the seizure focus (or foci) and also for purposes of functional mapping using electrical stimulation. We propose to administer computerized memory tasks during the intracranial EEG monitoring period. Memory testing may also occur during other patient visits for protocol 11-N-0051. This testing may occur during a pre-surgical outpatient visit or during Phase 1 (pre-implantation) monitoring, to establish baseline memory performance, or after the resection surgery, to identify potential changes in memory performance due to the resection. All testing associated with this protocol will be done during visits or hospitalizations for 11-N-0051, and this protocol involves no additional study visits. Some memory test sessions will include low-intensity electrical stimulation of the brain using the intracranial electrodes. During these sessions, brain stimulation trials will be interleaved with non- stimulation trials in a randomized fashion. EEG recordings will be retrospectively analyzed for the presence of biomarkers that correlate with successful memory performance, and test performance will be compared between the stimulation and no-stimulation conditions. The studies described here are voluntary and for research purpose only. They will not interfere with the clinical evaluation or decision-making process for epilepsy surgery. Outcome Measures The primary outcomes are (1) to identify biomarkers of successful memory encoding and retrieval, and (2) to identify brain regions that can be stimulated to affect memory performance. The secondary outcome is to identify biomarkers that can be used to predict cognitive impairment following resection surgery.