Responsive Neurostimulation for Intractable Epilepsy in Phelan McDermid Syndrome

Responsive neurostimulation (RNS) is an approved treatment for intractable epilepsy in the adult population but has not yet been approved for pediatric patients. We present here the first reported case of a 14-year-old adolescent with 22q13.3 syndrome (more commonly known as Phelan-McDermid syndrome) with intractable epilepsy who showed clinical improvement after implantation of an RNS device. The patient had trialed 10 antiepileptic drugs without improvement and despite magnetic resonance imaging (MRI) demonstrating left mesial temporal sclerosis (MTS), the patient was not considered as a candidate for temporal lobe resection due to multifocal seizure activity on electroencephalogram (EEG). At 23 months postoperatively, she has experienced 86.7% reduction in seizure frequency; a clinical improvement which emphasizes the importance of considering RNS treatment for those with intractable epilepsy in the pediatric population, even in the setting of known genetic syndromes.