Bithalamic Responsive Neurostimulation for Pediatric-onset Medication-resistant Epilepsy
Abstract number :
2.047
Submission category :
3. Neurophysiology / 3E. Brain Stimulation
Year :
2022
Submission ID :
2204242
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:24 AM
Authors :
Samuel Ahn, MD – UCLA; Benjamin Edmonds, MD – UCLA; Rajsekar Rajaraman, MD, MS – UCLA; Lekha Rao, MD – UCLA; Shaun Hussain, MD – UCLA; Jason Lerner, MD – UCLA; Raman Sankar, MD, PhD – UCLA; Joyce Matsumoto, MD – UCLA; Aria Fallah, MD, MS – UCLA; Hiroki Nariai, MD, MS, PhD – UCLA
Rationale: Children with medication-resistant generalized or multifocal epilepsy have limited treatment options. Deep brain stimulation (DBS) of the anterior nucleus of the thalamus is approved in adults with intractable focal epilepsy. However, the centromedian nucleus of the thalamus (CM) is postulated to be more appropriate to address generalized and multifocal neocortical epilepsies due to its diffuse cortical connections. We report our preliminary experiences with closed-loop responsive neurostimulation (RNS) of bilateral CM in 13 patients with pediatric-onset medication-resistant generalized and multifocal epilepsies.
Methods: Patients who were evaluated by the UCLA Pediatric Epilepsy Program and underwent bilateral CM RNS treatment were retrospectively identified. Clinical, demographic, and RNS programming data were abstracted from the electronic medical record.
Results: Thirteen patients (4 females, 9 males) were identified, with median age at implantation 13.7 (range, 3.6 – 22) years. Epilepsy types included Lennox-Gastaut syndrome (n=5), multifocal epilepsy (5), epileptic spasms (2), and genetic generalized epilepsy (1). Prior surgeries included VNS (n=8), corpus callosotomy (3), and focal resection (1). The median time from implantation to initial stimulation programming was 32 days. Detection algorithms were adjusted based on analysis of RNS recording data, with a focus on magnet swipes marking clinical seizure events. The common ictal EEG findings at CM were low-voltage fast activity and rhythmic spike-wave discharges. Clinical seizures were associated with RNS-recorded ictal activity by 100% in six patients, 80%-100% in four, 60%-80% in two, and 30%-40% in one. Detection and stimulation programming were further modified at follow-up visits based on reported seizure frequency. Subsequent adjustment of the RNS detection settings improved the capture of clinical seizures. Stimulation settings were configured in bipolar (contact-to-contact within electrode, n=7) or cathodal (contacts-to-cathode at device, 6) stimulation. Other modified parameters included burst duration (2-5 seconds), charge density (0.5-1 µC/cm2), pulse width (160 µs), and frequency (125 Hz). Six patients experienced sensorimotor (pain, abnormal movements) or neuropsychiatric (agitation, anxiety) side effects from cathodal stimulation when increasing charge density. Three patients had an infection of the device, resulting in deplantation. In seven patients with longer than 6 months postoperative follow-up, one became seizure-free, one had ~80%-90% seizure reduction, three had ~50%-70% reduction, and two had ~30-40% reduction.
Conclusions: Our experience supports bithalamic-CM RNS as a feasible option for children with medication-resistant generalized and multifocal epilepsy. CM electrodes are able to detect epileptiform activity, and stimulation may improve seizure frequency leveraging the RNS system's closed-loop concept. Complications from surgical procedures and stimulation-related side effects should be considered and monitored closely.
Funding: Epilepsy Foundation Greater Los Angeles, UCLA Children’s Discovery and Innovation Institute
Neurophysiology