Abstracts

RATIONALE: Vagus nerve stimulation (VNS) is considered an effective therapy for patients with intractable seizures. Magnet-induced manual activation of the stimulator is an important component of VNS. Even though the efficacy of VNS has been well established in controlled studies, the efficacy of the magnet activation has been difficult to evaluate. We conducted a survey on the perceived efficacy and degree of satisfaction with the magnet use among patients treated with VNS at our institution.
METHODS: Of 78 patients who received VNS therapy for the treatment of epilepsy, 59 were able to complete the survey. Patients or caregivers were interviewed during regular office visits or over the phone. A standard questionnaire was used and an effort was made by the interviewers not to influence the patient[ssquote]s responses.
RESULTS: Mean age of the population was 30.4 years (r: 9-59 years). Thirty-eight (64.4%) subjects had partial epilepsy, 18 (30.5%) had secondary generalized epilepsy, and 3 (5.1%) had primary generalized epilepsy. Mean duration of VNS therapy was 30.9 months.
Survey results: overall efficacy of VNS was rated as [dsquote]very good[dsquote] or [dsquote]excellent[dsquote] by 23 patients (39.0%), and [dsquote]fair[dsquote] or [dsquote]poor[dsquote] by 21 (35.7%). Of 59 patients, 55 reported using the magnet. Magnet efficacy was rated as [dsquote]very good[dsquote] or [dsquote]excellen[dsquote] by 15 (31.3%) patients when used in partial seizures (PS)(n=48) and 13 (25.5%) in generalized tonic-clonic seizures (GTC) (n=51). Magnet use was considered [dsquote]ineffective[dsquote] by 21 (43.8%) patients in PS, and 16 (31.4%) in GTC.
When patients (n=59) were asked how much the possibility of magnet use influenced their decision to proceed with VNS, 31 (52.5%) answered as [dsquote]very much[dsquote], 13 (22.0%) [dsquote]not at all[dsquote]. When they (n=55) were asked if the magnet use has met their expectations, 29 (52.7%) responded [dsquote]yes[dsquote]. When they (n=55) were asked how much the magnet use changed their feeling of safety or confidence, 19 (34.5%) answered [dsquote]very much[dsquote], 27 (49.1%) answered [dsquote]not very much[dsquote].
CONCLUSIONS: Results of our survey indicate that almost 40% of the patients considered VNS therapy as very effective. As for the magnet use, between a fourth to a third of the patients considered it as very effective, whereas, close to half of the patients considered it essentially ineffective.
Interestingly, the prospect of magnet use to control seizures heavily influenced the decision to proceed with VNS therapy in slightly more than half of the patients. Despite a relatively low efficacy, only about half of the patients considered that the magnet use did not meet their expectations. About one third of the patients reported an increase in their self confidence because of the magnet use. These findings may be of help to physicians when counseling patients about the possibility of VNS.
(Disclosure: Honoraria - Cyberonics (Jorge Asconap ))