Study of Direct Brain Recording and Stimulation for Memory Enhancement

Overview

Background: \- Epilepsy is a seizure disorder. Sometimes it is treated with surgery. During surgery, electrodes are placed on or in the brain. Researchers want to learn more about memory and the brain. They want to do tests on people who are having epilepsy surgery. Objective: \- To learn more about memory and brain function by recording brain cell activity during memory tasks. Eligibility: \- Adults age 18 - 65 who have medically intractable epilepsy and will have electrodes placed to identify the source of their seizures. They must be currently enrolled in protocol 11-N-0051. Design: * Participants may do memory tests before the electrodes are put in, while they are in place, and after surgery. Researchers may stimulate areas of the brain with small pulses of electricity. * Researchers will start recording brain activity at least 12 hours after electrodes are placed. They will record while participants are awake and asleep. They will record before, during, and after seizures. * Participants may have up to 3 testing sessions daily over the 1-3 weeks the electrodes are in place. Each session will last 20-60 minutes. * Participants will play games on a laptop. Sometimes they may use a button or joystick. This can be done in bed in the hospital. * Participants may be given a list of words and asked to recall them in a short time. * Participants may be given pairs of items and asked to remember how they are related. * Participants may be asked to learn their way around a virtual town on the computer. Their eye movements may be tracked by a small camera.

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.