Refractory Localization-related Epilepsy Clinical Trial
Official title:
Intra-operative Detection and Localisation of High Frequency Oscillations in the ECoG to Guide Epilepsy Surgery
Epilepsy occurs in 0.5-0.7% of the population, of which 25% are children. 30% Of patients with focal epilepsy do not respond well to medication and half of them are eligible for epilepsy surgery. In recent years, the importance of early epilepsy surgery has been stressed, as successful surgery may lead seizure and medication freedom and improved social and cognitive development, especially in children. The current success rate of epilepsy surgery is around 65%; During surgery intracranial electrocorticography (acute ECoG, aECoG) is recorded in some medical centers. The presence of epileptiform brian activity, spikes, identified by clinical neurophysiologists, is used to guide the neurosurgeon in the extent of the brain tissue that needs to be resected. Spikes are considered markers of the presence of epilepsy. High Frequency Oscillations (HFOs, >80-500Hz) in the ECoG have recently been identified as a new biomarker for epileptogenic tissue. Retrospective research shows that their local presence strongly relates to the seizure onset, and removal of tissue with HFOs could predict a better surgical outcome. The area showing HFOs usually overlaps with, but is smaller than the area with spikes, and HFOs do not tend to propagate to distant sites as spikes do. The identification of HFOs is more objective than of spikes and automatic detection software exists. A pilot study is performed to test the hypothesis : The intra-operative use of HFOs to delineate the epileptogenic cortex does not yield significantly worse outcome in seizure freedom than the current method based on spikes. Study design is a single blinded multi-center randomized controlled trial. In two Dutch centers, the VU medical center ( Amsterdam) and University Medical Center Utrecht. The study population (sample size 78) consists of patients of all ages with refractory epilepsy undergoing epilepsy surgery with aECoG to guide the extent of the resection. Eligible patients are randomised, after informed consent, into group 1 (HFOs) in whom a resection guided by HFOs in the aECoG (new), or into group 2 (spikes) in whom a resection is guided by epileptiform spikes in the aECoG (current standard). Ictiform spike patterns will always be resected. Main study endpoint is outcome after epilepsy surgery after 1 year of follow-up dichotomized in total seizure freedom (Engel Ia&b) vs. seizure recurrence (Engel Ic-IV).
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