Abstracts

RATIONALE: Vagal Nerve Stimulation is an accepted and emergent treatment for drug-resistant epilepsy. Previous studies have compared the response of various stimulator settings with a prospective baseline period. No studies have as yet examined the effect in comparison with a [ssquote]placebo[ssquote] treatment period, where the device is turned off.
METHODS: This was a randomised crossover study comparing the effect of three different stimulus settings ([ssquote]off[ssquote], [ssquote]standard[ssquote], and [ssquote]rapid[ssquote] stimulation). Each treatment phase lasted six months, and seizure frequency was monitored by a observer who was blinded to the current settings. Separate investigators were responsible for programming the device.
RESULTS: Twenty one patients with refractory epilepsy were randomised into this study. Median age was 25yrs and median duration of epilepsy was 21 years. Two patients were on one AED,10 patients were on duotherapy, and nine were on three or more AEDs. In addition, four had previously undergone epilepsy surgery.
Median reduction in GTC seizures during standard and rapid stimulation was 31% and 24% respectively. Median reduction in complex partial seizures was 0% during rapid stimulation and 50% during rapid stimulation. See table below for responder rates.
Twelve patients started all three treatment phases. Three patients were withdrawn from the study because of adverse events; one patient suffered pain at the stimulator site, and two had psychiatric adverse events (in one case, an exacerbation of previously documented psychosis). One patient withdrew because of worsening seizures, two withdrew consent, and there were an additional two protocol violations.
CONCLUSIONS: Vagal nerve stimulation is a safe, well-tolerated , and effective treatment for epilepsy, even in this particularly refractory group of patients.[table]
Support: Stimulators and study materials were supplied by Cyberonics[copy].
Disclosure: Materials - VNS Stimulators supplied by Cyberonics