Multi-level Approach of Brain Activity Using Intracranial Electrodes in Epileptic Patients

Study Overview
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Brief Summary
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The main goal of this project is to study the mechanisms of epileptic activities using intracranial macro and micro electrodes in epileptic patients undergoing pre-surgical investigation. The recordings will also be used to study physiological mechanisms like sleep and different cognitive functions.

Official Title
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Multi-level Approach of Brain Activity Using Intracranial Electrodes in Epileptic Patients

Conditions
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Focal Epilepsy, Electrodes, Implanted, Cognitive Function, Neurophysiology

Intervention / Treatment
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* Device: Intracranial macro-microelectrode recording


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with focal drug-resistant epilepsy Patients who undergo a presurgical evaluation with intracranial electrodes in the videoEEG unit of the Neurology department at the Pitié-Salpêtrière hospital. Patients who have been informed and provided written informed consent to take part in the study Exclusion Criteria: Contraindication for an intracranial investigation (with macro-electrodes) : intercurrent infectious syndrome, decompensated associated pathology (cardiac, pulmonary, renal, hepatic), patient with increased risk of infection (ex: under immunosuppressive therapy) Pregnant or parturient woman Breastfeeding woman Minor person or legally protected adult (tutelage, legal guardianship, maintenance of justice)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Macro-microelectrode implantation<br>Implantation of macro-micro electrodes of the Adtech Benkhe-Fried type in epileptic patients who are undergoing evaluation with intracranial EEG electrodes | Device: Intracranial macro-microelectrode recording<br>* Additionnally to clinical macroelectrodes, Benkhe-Fried depth macro-microelectrodes will be implanted and recorded during the pre-surgical investigation of epileptic patients<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Identification of single unit changes at seizure emergence | In order to identify biomarkers of epileptic seizures we will study single neuron activities (firing rate) using spike sorting at different time periods (before, during and after seizures and during interictal periods) We expect to observe significant changes in firing rate across the different time periods. | Whole duration of the clinical inverstigation, until 4 weeks | 
| Identification of local field potential (LFP) changes at seizure emergence | In order to identify biomarkers of epileptic seizures we will study LFP power using time frequency analysis at different time periods (before, during and after seizures and during interictal periods) We expect to observe significant changes in LFP power across the different time periods. | Whole duration of the clinical inverstigation, until 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of single unit activity before seizure according to brain localization | We will compare firing rate before seizure according to brain regions (anatomy and involvement in the seizure onset zone) | Whole duration ofthe clinical inverstigation, until 4 weeks | 
| Identification of single unit changes during physiological brain activity | We will compare firing rates during resting states and stimulus induced states. We expect to observe significant changes in firing rate between states. | Whole duration ofthe clinical inverstigation, until 4 weeks | 
| Identification of LFP power changes during physiological brain activity | We will compare LFP power during resting states and stimulus induced states. We expect to observe significant changes in LFP power between states. | Whole duration ofthe clinical inverstigation, until 4 weeks | 
| Multilevel study of brain activity | We will look for correlation between firing rates and LFP power changes. | Whole duration ofthe clinical inverstigation, until 4 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Microelectrodes, Seizures, EEG