Contribution of High Resolution EEG Functional Connectivity Measures to Presurgical Evaluation of Patients With Intractable Epilepsy

Contribution of High Resolution EEG Functional Connectivity Measures to Presurgical Evaluation of Patients With Intractable Epilepsy

Electroencephalography (EEG) with very high spatial resolution (HR-EEG, 256 electrodes) allow for better analysis of local and global activity of the cerebral cortex, as compared with conventional EEG. Since January 2012, the Neurology Department of CHU Rennes is the first clinical service in France equipped with such a system.

Applied to HR-EEG recordings, brain connectivity methods are likely to provide essential information (in the form of "connectivity graphs") on cortical networks, either dysfunctional or not, involved in the generation of interictal paroxysms (like spikes or spike-waves) and during seizures.

So far, many methods have been proposed (see for a review: Wendling et al., 2009; Wendling et al., 2010). However, since each method is highly sensitive to the type of model that is assumed for the underlying relationship between distinct brain regions (Ansari-Asl et al., 2006), none of them has yet demonstrated its effectiveness.

Inclusion Criteria Patients:

• Being more than 18 years old,
• Having a chronic partial epilepsy resistant to medical treatments well administered and well followed in the course of pre-surgical assessment.

Inclusion Criteria Healthy Volunteers:

• Being French native speaker,
• Being more than 18 years old,
• Being right-handed.

Exclusion Criteria Patients:

• All patients for whom a preoperative surgical exam is not suitable,
• Any patient with psychiatric disease or intellectual disorder such that informed consent could not be obtained,
• Any patient with no abnormal EEG during intercritical phases,
• All patients presenting psychiatric, neuropsychological or developmental difficulties in addition to epilepsy,
• Adult persons subject to legal protection (judicial protection, temporary guardianship/guardianship, administrative supervision), persons deprived of their liberty and pregnant or lactating women.

Exclusion Criteria Healthy Volunteers:

• The presence of any psychiatric, neuropsychological, and developmental disorder,
• Any uncorrected visual impairment,
• Any trouble or delay in learning to read / speak or write French,
• Being fully bilingual or multilingual
• Medication, treatment and / or substances that may alter or modify brain functions,
• Adult persons subject to legal protection (judicial protection, temporary guardianship/guardianship, administrative supervision), persons deprived of their liberty and pregnant or lactating women.