The role of Vagus nerve stimulation in epilepsy with eyelid myoclonia - A case series.

OBJECTIVE

To study the effectiveness of vagus nerve stimulation (VNS) in patients with epilepsy with eyelid myoclonia (EEM, previously known as Jeavons Syndrome).

BACKGROUND

EEM is an epilepsy syndrome characterized by eyelid myoclonia, eyelid closure-induced generalized EEG paroxysms or seizures, and photosensitivity. Many patients have drug-resistant epilepsy; however, the effectiveness of VNS in this epilepsy syndrome has not been well studied.

METHODS

This is a single institution retrospective observational study of patients with EEM. Among a database of 134 patients with EEM, we identified those treated with VNS. Epilepsy history, VNS parameters, and response to VNS were abstracted.

RESULTS

We identified 12 patients who were treated with VNS (50% female). The median age of epilepsy onset was 5 (range 4-14) years; age of VNS implantation was 16 (range 6-33) years, and median duration of VNS treatment was 13.5 (range 0-24) years. Four patients (33.3%) were responders reporting greater than 50% improvement in seizure frequency. All four patients (33.3%) showed response with generalized tonic-clonic seizures, myoclonic seizures, and three patients (25%) reported response with eyelid myoclonia and absence seizures. One patient had the VNS explanted due to lack of efficacy and one had it turned off for enrollment in a clinical trial. The median maximum tolerated output current settings for our cohort were 1.75 mA (IQR 1.38-1.94; range 0.75-2.25) with an OFF time of 1.8 min (IQR 1.1-3, range 0.2-3) and median duty cycle of 24% (IQR 16-29; range 12-58).

CONCLUSIONS

From this small case series of patients with EEM, four (33.3%) were responders to VNS, with improvement noted in multiple seizure types. This indicates the potential role of VNS for patients with EEM.