Abstracts

Rationale: The primary aim of this study is to investigate seizure outcomes following responsive neurostimulation (RNS) placement and analyzing differences of outcomes based on demographics and prior epilepsy surgery.


Methods: A retrospective review was conducted on drug resistant epilepsy patients who underwent RNS placement in our institution from 2018 to 2023. We calculated Engel and ILAE seizure outcomes scores at 12- and 24-months follow-up.


Results: A total of 24 patients were included in the study. Fifty percent (n = 12) of the patients identified as Black persons and the rest as White persons. Fifty-four percent (n = 13) identified as biological females. The most common lead placement was bilateral or unilateral medial temporal (42%, n=10) followed by unilateral medial temporal and neocortical temporal (21%, n = 5). Twelve patients had prior epilepsy surgery. Nineteen patients were available for the 12-months analysis of which 84% (n=16) had focal seizures with impaired awareness as the most common semiology. Forty-two percent (n=8) had RNS placed within 15 years of the epilepsy diagnosis. At 12 months follow-up, 84% (n =16) and 74% (n= 14) had a positive outcome on Engel (I-III) and ILAE (1-4) scores. Forty-four percent of good outcome patients had prior epilepsy surgery versus 66% in the poor outcome group (Engel IV) despite a lower rate of mesial temporal sclerosis and structural causes in the good outcome group (Table 1). There was no significant difference in outcomes in those with (83%) and without (81%) a previous temporal lobectomy at 12 months follow-up.

Thirteen patients were available for the 24-month follow-up. Sixty-seven percent of patients with a previous resection (n = 6) had a good Engel and ILAE outcome vs. 100% of those without a prior surgery (n = 4).


Conclusions: Responsive neurostimulation is a viable treatment tool to improve seizure outcomes for patients with drug-resistant epilepsy at the 12-month and 24-month follow-up. The predominant benefit is seen in the first 24 months. Patients with a previous history of epilepsy surgery were more likely to have worse outcomes, despite having higher incidence of structural etiology or mesial temporal sclerosis. This may suggest more difficult to treat epilepsy or lack of focused targets for neurostimulator therapy. Larger clinical studies of real-world data would be needed to determine efficacy in these populations.


Funding: None