Responsive neurostimulation in children, adolescents, and young Adults-Longitudinal effectiveness and safety

Drug-resistant epilepsy (DRE) remains challenging to treat, and seizure control often fluctuates over time. Responsive neurostimulation (RNS) is increasingly used in pediatric and young adult populations, yet long-term effectiveness and safety data are limited. We evaluated longitudinal seizure control trajectories and safety of RNS in children, adolescents, and young adults treated at our center. Seizure frequency was assessed at approximately 6-month intervals from serial follow-up visits through the most recent follow-up, with each sampled visit categorized by ≥ 50 % (all-responder, AR) or ≥90 % (super-responder, SR) seizure reduction. We examined the persistence and durability of seizure control and used recurrent-event regression to identify clinical modifiers of sustained response. Responder rates improved over time, with 57 % and 75 % of patients achieving AR status at 24 and 47 mean months post-implantation, respectively; corresponding SR rates were 22 % and 33 %. Once achieved, seizure control was typically maintained: the probability of remaining an AR for 24 months was 70 %, and the median proportion of follow-up with sustained response exceeded 85 % across age groups. Concurrent epilepsy surgery favored maintenance of AR status (HR 1.83, p = 0.02), while syndrome-related epilepsies reduced the likelihood of sustained SR status (HR 0.30, p = 0.03). Age at implantation and responder status at 24 months both associated with long-term seizure control. Serious (0.032 events/person-year) and non-serious (0.038 events/person-year) adverse effects were infrequent. RNS provided durable benefit for most, though not all, patients, reflecting the dynamic nature of seizure control. The favorable effectiveness and safety profile support use of RNS in young patients with DRE.