Abstracts

Rationale: External trigeminal nerve stimulation (eTNS) was recently approved in Europe as treatment for drug resistant epilepsy for those aged nine years and above. A self-adhesive electrode is placed on the forehead and attached via wires to the Monarch device (Neurosigma, USA). The ophthalmic divisions of both trigeminal nerves are stimulated at 120 Hz, for 7 seconds out of 30. Patients set the current so that stimulation is noticeable, but not uncomfortable (< 10 mA) and aim for a minimum of 8 hours use overnight. In a recent small randomised-controlled trial, 50 patients with drug resistant focal epilepsy were randomised to eTNS or active control. After 18 weeks 40.5% of the treatment group had a 50% or more reduction in seizure frequency compared to 15.6% in the control group (DeGiorgio et al. 2013). Methods: We offered patients with drug resistant epilepsy (any classification) eTNS. To audit outcome we obtain baseline seizure frequencies, quality of life (QOLIE-10), mood (Beck Depression Inventory, BDI), sleep quality (Pittsburgh Sleep Scale) and daytime sleepiness (Epworth Scale). In patients with learning disabilities, quality of life is assessed using EDQOL. We reassess these parameters at 4, 12 and 18 weeks. Results: Sixteen patients with drug resistant epilepsy started on eTNS within the adult epilepsy service and more recently 3 within the paediatric service, one of whom developed depigmentation at the site of attachment. Amongst the first 16 patients all but two tolerated the device well. One discontinued use because daily minor seizures, which previously clustered in the morning and evening, became intrusive and spread out, another because of disliking the sensation. Another patient had slight transient forehead reddening in hot weather. The device was worn between 6 and 12 hours a night (median 10) with a median current of 5 mA (range 2.6-7.6). In only a few instances was contact lost overnight. Two patients had concurrent significant medication changes so efficacy was uncertain. Both continue to use the device. Two other patients had daily absences they were unable to count; both reported more good days on treatment.Of the remaining 10 patients, data are available at 12 weeks of treatment so far. Mean seizure rate before treatment was 2.9/week (range 0.7-7.1), which reduced to 2.1/week (0.3-4.6; paired student t-test p=0.09) for the 12 weeks after treatment. Six patients had a 30% reduction in seizures of whom 4 had a 50% reduction. The QOLIE-10 weighted score improved from a mean of 37 (range 4-87) pretreatment to 24 (2-48) at 12 weeks (n=12; p=0.03). The BDI improved from 12 (2-26) pretreatment to 8 (0-14; n=12; p=0.03). There was a slight improvement in both sleep scales (Pittsburg 7 (3-16) to 5 (1-10), p=0.04; Epworth 11 (1-20) to 10 (1-17); p=0.13; n=12).Conclusions: These data support the safety and tolerability of eTNS. They demonstrate improved seizure control in a number of patients, along with improvements in measures of quality of life, mood and sleep. Declaration: The devices and electrodes were supplied by Neurosigma. This report is independent of the company.