Functional connectivity in patients with non lesional partial epilepsy
Edgard Andrade, MD, MS
Research Project Description
Epilepsy affects about 1 % of the general population, accounting for grossly 60 million cases worldwide but almost 10 % of patients are pharmaco-resistant and therefore surgical resection is considered as an option. The success of epilepsy surgery is defined by the identification of the ictogenic zone, e.g., the area of the brain causing seizure onset, however, seizure freedom is only reached in 60 % of the cases despite of detailed analysis of the ictogenic neuronal network with current available tools. Thus, we are using functional and effective connectivity methods to obtain information on seizure directionality. We are developing groundbreaking knowledge by creating maps of neuronal interactions for the study of ictogenic and epileptogenic mechanisms based on the novel hypothesis that the limbic system, as part of the fronto-temporal network defines directionality in patients with complex partial seizures and normal 3.0 Tesla brain MRI. Hence, we are utilizing a functional connectivity tool called Pairwise Granger causality (PGC) to better define ictogenic mechanisms in human scalp and intracranial EEG recordings. Boot-strapping methodologies have been used to address the issue of testing statistical significance of using PGC. A database has been created and is used for data mining. Preliminary analysis reveals a consistent intra-hemispheric ictal; propagation. However, further evaluation of affected subjects is required. Medical students will actively and directly participate in clinical evaluation of affected patients, EEG and brain MRI interpretation and Granger causality testing prior and during surgical evaluation of candidates. No funding is available.
- Andrade E, Liu Z, Cadotte A, Talathi S, Carney P. Granger causality predicts seizure directionality in patients with non lesional partial epilepsy refractory to medical treatment. In press.
- Carney P, Andrade E, Talathi S, Geyer J. EEG in the newborn, Infant and adolescent in clinical sleep disorders by Carney P, Geyer J, Berry R( EDS) 2011. Lippincott Williams & Wilkins. ISBN -10: 07817-8692-4