Bilateral centromedian nucleus of thalamus responsive neurostimulation for pediatric-onset drug-resistant epilepsy

Abstract

Neuromodulation therapies offer an efficacious treatment alternative for patients with drug-resistant epilepsy (DRE), particularly those unlikely to benefit from surgical resection. Here we present our retrospective single-center case series of patients with pediatric-onset DRE who underwent responsive neurostimulation (RNS) depth electrode implantation targeting the bilateral centromedian nucleus (CM) of the thalamus between October 2020 and October 2022. Sixteen patients were identified; seizure outcomes, programming parameters, and complications at follow-up were reviewed. The median age at implantation was 13 years (range 3.6-22). Six patients (38%) were younger than 12 years of age at the time of implantation. Ictal electroencephalography (EEG) patterns during patients' most disabling seizures were reliably detected. Ten patients (62%) achieved 50% or greater reduction in seizure frequency at a median 1.3 years (range 0.6-2.6) of follow-up. Eight patients (50%) experienced sensorimotor side effects, and three patients (19%) had superficial pocket infection, prompting the removal of the RNS device. Side effects of stimulation were experienced mostly in monopolar-cathodal configuration and alleviated with programming change to bipolar configuration or low-frequency stimulation. Closed-loop neurostimulation using RNS targeting bilateral CM is a feasible and useful therapy for patients with pediatric-onset DRE.

Keywords: centromedian nucleus; drug‐resistant epilepsy; epilepsy surgery; neurostimulation; thalamus.

Figure 1

a: PDMS EEG evaluation. Examples of electroclinical seizures from the NeuroPace Patient Data Management System (PDMS) for two patients with RNS depth electrode implant targeting bilateral CM before (left-hand column) and after (right-hand column) stimulation activation. Patient activated magnet swipes (M), automated detections (A1, A2, B2), and stimulation events (Tx) marked with yellow arrows. Spectrograms are shown below of the identical epochs. LCM: left centromedian nucleus, RCM: right centromedian nucleus. b: Responder rates with subgroup comparisons. Responders were defined as having ≥50% reduction in seizures. Fisher exact test was used for each subgroup comparison, and p values are listed. The number of responders in each subgroup (n) is displayed within the columns.