Bilateral Neocortical Temporal Lope Epilepsy Managed by Responsive Neurostimulation. (16th November 2020) - Bakr, Salma
Abstract: INTRODUCTION: Patients with refractory neocortical temporal lobe epilepsy (nTLE) remain challenging surgical candidates owing to the difficulty of localizing seizure foci and the proximity of eloquent areas including the language and auditory cortices. Phase I pre-operative evaluation often fails to accurately localize seizure onset zones (SOZ), necessitating the use of invasive intracranial encephalography (iEEG). To our knowledge, "bilateral neocortical temporal lobe epilepsy" (bnTLE) has never been discussed in the literature before. METHODS: We identified three cases of bnTLE at OHSU who exhibited evidence of bilateral neocortical temporal seizure onset and had a musical or auditory component to their seizures, with localization confirmed by intracranial EEG monitoring. The electronic medical records of included subjects were retrospectively reviewed. RESULTS: iEEG (depth electrodes with or without subdural electrode strips) localized SOZs to the temporal neocortices in all three cases. All three patients were implanted with bilateral superior temporal gyrus (STG) subdural electrode strips for treatment with RNS. One patient is currently seizure-free after 2.5 years of treatment with RNS on 3 anti-epileptic drugs (AEDs). Another is not receiving stimulation from RNS due to side effects and continues to have 1–2 disabling seizures per month on 4 AEDs and vagal nerve stimulation (VNS). The third has experienced an 93% reduction in seizure frequency relative to pre-surgery and has not reduced AEDs from her regimen of 3 medications. CONCLUSION: bnTLE describes a specific subset of neocortical temporal lobe epilepsy that is particularly challenging to diagnose and treat since bilateral resection is not an option due to the presence of eloquent areas in the dominant temporal neocortex. This case series suggests that bilateral RNS could be a safe and effective treatment modality for this complex condition. RNS stimulation side effects are rare but warrant further study. The utility of RNS therapy for bnTLE requires further assessment.