Cortical Excitability and Treatment Response in People with Epilepsy

Electrophysiological Markers of Cortical Excitability to Predict Response to Treatment with Anti-seizure Medication - the ECORTA Study

Epilepsy is a medical condition marked by the occurrence of unpredictable, recurrent seizures. One-third of people with epilepsy continue to experience seizures, despite having attempted multiple forms of anti-seizure medication (ASM). Currently, response to ASM is assessed on a trial-and-error basis as their efficacy can only be determined in hindsight. This causes delays in finding the proper treatment per individual. Responsiveness of the outer brain layer to external stimuli, termed cortical excitability (CE), may be used as additional means of treatment evaluation.

In this study, the investigators aim to measure CE before and after starting with ASM, so as to determine whether indicators of CE can be used to predict favorable response to the medication. Participants in this study are adult individuals with uncontrolled seizures that will start with the novel anti-seizure medicine cenobamate. The investigators hypothesize that, after starting with ASM, the CE will decrease in people with epilepsy who show a favorable response to the medication. Conversely, the investigators anticipate that the CE will not decrease in those that do not react to the mediation.

The investigators will address this hypothesis by evaluating both brain activity (electroencephalography, EEG) during rest and during different types of stimulation (magnetic, light flashes). Besides, the investigators will measure the subjective experiences of participants by using questionnaires on the quality of life and feelings of anxiety or depression. These measurements are performed at a baseline instance, just before starting with ASM, and at two instances after start with the ASM. Participants in the study will track the occurrence of seizures - using a diary - from 12 weeks before ASM start up till 12 months after ASM start. The investigators will compare seizure frequency with both changes in brain activity and subjective experiences by the participants.

Inclusion Criteria:

• In agreement with their own neurologist to initiate adjuvant treatment with cenobamate
• Diagnosed with refractory focal epilepsy, which means two ASMs failed to cause seizure freedom.
• Age of 18 years or older
• Having kept a seizure diary for the past 12 weeks
• At least one seizure in the past 12 weeks.

Exclusion Criteria:

• Photosensitive epilepsy
• Any device or structure in the skull or in close proximity of the head area containing metal, including cochlear implants, implanted neurostimulators, cardiac pacemakers and intracardiac lines.
• Persistent skull opening following trauma or surgery
• Evidence (clinical or radiological) of major structural abnormality of the motor cortex or pyramidal tracts
• Any major psychiatric condition such as a psychotic disorder
• Pregnancy
• Learning disabilities preventing the comprehension of oral and/or written instructions