Response to vagus nerve stimulation in people with ring chromosome 20

Ring chromosome 20 is a rare genetic syndrome characterized by epilepsy, intellectual disability, and other neurodevelopmental abnormalities. Seizures in ring chromosome 20 are often drug-resistant and debilitating. For patients with drug-resistant epilepsy, non-medical options are often considered; however, the efficacy of these interventions is not well-understood. In this retrospective case series, we investigated the utility of vagus nerve stimulation in people with ring chromosome 20.

Patients were identified from our research/clinical databases, and with the assistance of a patient support group. Patients and/or caregivers were interviewed by phone or video teleconference. Data collected included demographics, epilepsy characteristics, and response to medical and non-medical treatments, including vagus nerve stimulation.

Fourteen patients were included in the study. 11/14 reported some improvement in epilepsy following vagus nerve stimulator implantation, including five with reduced seizure frequency, three with shorter seizure duration, three with reduction or elimination of non-convulsive status epilepticus or specific seizure types, two with reduced need for rescue medication, and two shorter post-ictal signs/symptoms. Two patients were reported to have improved cognitive function and one a reduction in aggressive behaviour.

Overall, vagus nerve stimulation appears to be an effective treatment for some patients with ring chromosome 20 and drug-resistant epilepsy.