Source and network analyses of focal epileptic activity during sleep

• Applicant: Dr. Bernd Vorderwülbecke
• Subject Area: Clinical Neurology; Neurosurgery and Neuroradiology
• Term: from 2019 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 422589384

Focal epilepsies are no longer considered a dysfunction of circumscribed brain pathologies but of widespread neuronal networks. This paradigm shift has major implications for presurgical epilepsy evaluation, aiming at localising the epileptogenic zone in patients with pharmacoresistant focal epilepsy, but also for our pathophysiological understanding of epileptic activity per se. Sources and networks of epileptic activity can be mapped based on electroencephalographic (EEG) data. Electrical Source Imaging (ESI) plots the sources of epileptic discharges within a 3D head model. Subsequently, information flow between the sources can be evaluated via Directed Connectivity (DC) analyses. Sources that drive epileptic activity are hereby distinguished from those secondarily activated. ESI and, more recently, DC analyses have started to prove their clinical value for presurgical epilepsy evaluation as validated by invasive EEG studies and postsurgical seizure outcomes. Most reliable results have been obtained from high-density EEG with up to 256 scalp electrodes. In focal epilepsy, sleep can facilitate epileptic seizures, and the frequency of interictal discharges increases with deepness of sleep. However, until now, ESI and DC studies of epileptic networks have only been performed during wakefulness. The proposed project aims at assessing sources and drivers of interictal epileptic activity during sleep and wakefulness. Using high-density EEG, patients with sleep- and wake-related seizures will be evaluated, as well as healthy control subjects. The results promise new pathophysiological insight into the interaction of focal epileptic activity and sleep.

• DFG Programme: Research Fellowships
• International Connection: Switzerland
• Host: Professor Serge Vulliémoz, Ph.D.