Abstracts

RATIONALE: Patients treated with vagus nerve stimulation (VNS) for refractory epilepsy can self-administer additional stimulation trains by applying a magnet in order to interrupt seizures. There are no reports in the literature on the efficacy of such additional stimulation. METHODS: In 22 out of 29 patients (12F, 10M) with complex partial seizures (CPS) treated with VNS at Ghent University Hospital, reliable information on magnet use and seizure occurrence was obtained. Three out of 29 patients became seizure free before the magnet was used; in 4 patients no reliable information could be obtained. The efficacy of additional stimulation administered by the patient or a care-giver in terms of seizure reduction was prospectively evaluated. RESULTS: VNS reduced overall seizure frequency in 22 patients with 58.6% (range: 16.7-100%) during a mean follow-up of 27 months (range: 5-60 months). Five patients (23 %) were unable to apply the magnet because there was no aura, seizures were brief or care-givers unavailable. In 6 patients (27%) no effect of the magnet was reported. Eleven patients (50%) reported an effect of the magnet; two of them were able to prevent or abort CPS themselves. In nine patients the magnet was commonly applied by a care-giver. This allowed to abort both CPS (n=8) and generalized seizures (n=2). Six out of 11 patients who benefited from magnet use ultimately became responders (seizure reduction >50%). CONCLUSIONS: In 50% of patients who are able to self-administer or receive additional magnet stimulation seizures can be interrupted. More than half of the patients who report effect of magnet use become responders. (Supported by Grant BOZF 01105399 from Ghent University; Grant 1.5.236.99 from the Fund for Scientific Research-Flanders and The Clinical Epilepsy Grant 1998-2000)