Abstracts

Rationale: Epilepsy affects up to 80% of patients with Sturge Weber Syndrome (SWS). Medications fail to control seizures in 50%. Surgical options include resection, lobectomy, hemispherectomy, callosotomy, and vagus nerve stimulation. The Responsive Nerve Stimulation (RNS) system is indicated as adjunctive therapy for refractory, focal-onset seizures. The system continuously monitors brain electrocorticogram (ECoG) activity through intracranial electrodes and delivers stimulation when patient-specific epileptiform activity (EA) is detected. The system stores ECoG samples allowing for physician review in a naturalistic setting. RNS EcOG has been used to assess potential response to new anti-seizure medication (ASM) via decrease in EA within the first 4 weeks of ASM introduction. This has not been evaluated in cenobamate, the most recent FDA approved ASM for focal onset seizures.

In this case report, we present two novel approaches of SWS-related epilepsy: 1) RNS and 2) cenobamate and evaluate changes in EA and clinical outcome.

Methods: The patient is an adult male with SWS and seizures beginning at 16 yo. Focal seizures are characterized by behavior and speech arrest with occasional progression to bilateral convulsion. Intracranial monitoring with grid and strip electrodes demonstrated seizure onset localizable to the right frontal region, adjacent to radiographic gyral susceptibility and leptomeningeal enhancement. The patient underwent RNS System placement with two cortical strip leads in a parallel orientation bordering the onset zone. Two additional non-connected cortical strip leads were placed in perpendicular orientation to the active electrodes (Figure 1). Detection and stimulation settings were optimized and tracked over the course of treatment. ASMs were adjusted per standard of care.

Results: Pre-implant seizure frequency was 15 to 30 seizures daily. One year following implantation, seizure frequency was 1.5 seizures daily. Following addition of cenobamate, and titration to 200mg/day, the patient reported a 4-month seizure-free period with wean of lacosamide and 50% dose reduction of clobazam. In this interval, daily detections of EA were reduced by 94% (from 718/day to 40/day). Long episodes (prolonged detections) were reduced by 85% (Figure 2). Based on epileptologist review of ECoG data, long episodes in this patient accurately represent the patient’s EcOG seizures.

Conclusions: Our experience demonstrates that brain-responsive neurostimulation can be a safe and effective surgical alternative in the treatment of a patient with SWS and medically intractable focal-onset seizures. RNS System allows for tailored therapeutic strategies based on patient response over the course of treatment. Stimulation and electrode polarities may be adjusted to treat a specific region of neocortex. Data from the RNS System may be monitored to evaluate response of new ASMs. In addition, attainment of periods of seizure freedom may be possible in similar patients with highly refractory regional epilepsy with neurostimulation and novel medication strategies. This case report represents a paradigm shift in the treatment of intractable focal epilepsy in SWS with brain-responsive stimulation.

Funding: Please list any funding that was received in support of this abstract.: None.