Electrophysiological Biomarkers in MTLE Patients.

Not Applicable

Terminated

Interventions: Device: Asynchronous distributed multi-electrode stimulation (ADMES) using an implantable neurostimulation device

Brief Summary: The investigators plan to enroll individuals with medical temporal lobe epilepsy who are undergoing surgical workup with clinically implanted intracranial electrodes. The study intends to administer computerized memory tasks and stimulation during the intracranial Electroencephalography (EEG) monitoring period.

Detailed Description: This is a nonrandomized interventional trial that will apply brain stimulation via clinically implanted intracranial electrodes to subjects with medial temporal lobe epilepsy with the purpose of identifying biomarkers related to the pre-ictal state; to perform an acute parameter search to determine the stimulation pattern that most effectively modifies these biomarkers and to identify changes in memory (free recall) during asynchronous distributed multi-electrode stimulation (ADMES).

Recruitment & Eligibility

Inclusion Criteria

Provision of signed and dated informed consent form
Male or female, aged 18-65
Diagnosed with lesional or non-lesional mesial temporal (hippocampal) seizure onset confirmed on SEEG monitoring
Implanted with depth electrodes for localization of seizure onset with multiple hippocampal electrode arrays

Exclusion criteria:

Exclusion Criteria

Not provided

Arm && Interventions

Group	Intervention	Description
Brain stimulation via clinically implanted electrodes	Asynchronous distributed multi-electrode stimulation (ADMES) using an implantable neurostimulation device	Brain will be stimulated in different patterns including synchronized or asynchronous current.

Primary Outcome Measures

Name	Time	Method
Change in Intracranial EEG Recording: Synchrony From Baseline	Baseline, up to 6 weeks postintervention	Synchrony will be compared between baseline/sham and stimulation trials to determine if asynchronous stimulation modulates synchrony during the preictal, ictal or post ictal states. Synchrony is a measure of how any pair of regions communicate with one another. Synchrony is measured as the correlation \[-1 to 1\] between two time series. The investigators anticipate that a decrease in synchrony (correlation approaching 0) is associated with improved outcome.
Change in Intracranial EEG Recording: Spectral Power From Baseline	Baseline, up to 6 weeks postintervention	Spectral power will be compared between baseline/sham and stimulation trials to determine if asynchronous stimulation modulates spectral power during the preictal, ictal or post ictal states. Spectral power is measured in microvolts. A change in either direction from baseline is associated with a better outcome.

Secondary Outcome Measures

Name	Time	Method
Changes in Memory During Brain Stimulation From Baseline	Baseline, up to 6 weeks postintervention	Patients will be asked to recall a list of words after a 20-second delay in which they will do simple math problems to ensure long-term memory encoding. Three \~1-2-hour sessions will be performed; each session will consist of 24 free recall tasks (12 during ADMES and 12 with no stimulation). The memory score will be assessed as the percentage correct out of 12. The higher the percentage recalled, the better the score.