Abstracts

Rationale: Multiple tubers in tuberous sclerosis complex (TSC) patients cause intractable epilepsy. The epileptic network with multiple tubers complicated to localize the epileptogenic zone for cortical resection. High frequency oscillations (HFOs) on intracranial video EEG (IVEEG) indicated the epileptogenic zone. We hypothesize that maximum resection of cortex with wide-spread HFO in TSC patients achieves good seizure outcome. Methods: We analyzed occurrence rate (OR) of interictal HFOs at 80-200Hz (ripples) and 200Hz (fast ripples: FRs) between groups A (seizure free) and B (residual seizure). We analyzed resection ratio of area including seizure onset zone, electrodes with high OR of ripples, and FRs.Results: We collected 10 patients (A: 7 patients; B: 3). The distribution of fast ripples was wide-spread (A: 13-41 electrodes [26]; B: 9-66 [31]; p=0.79) and distributed to multiple clusters (A: 2-6 clusters [4]; B: 1-4 [2]). The resection ratio of electrodes with high OR of FRs showed significant difference and high correlation ratio between groups A and B (A: 65-100% [78%]; B: 24-78% [51%]; p=0.034; correlation ratio=0.60). There was no significant difference of resection ratio of both seizure onset zone and electrodes with high OR of ripples between groups A and B. Conclusions: The extensive and multiple areas with FRs indicated wide-spread epileptic network in TSC patients. Resection of cortex with interictal fast ripples on IVEEG correlated with good seizure outcome in a subset of TSC patients.