Abstracts

Rationale: We are presenting a 10 year experience after implant with the Vagus Nerve Stimulator (VNS) in refractory epilepsy patients in a total population of 540 patients. 220 (40.7%) are mentally challenged. All patients initially were on polypharmacy (2-4 drugs). We asked the question: could VNS adjunctive therapy contribute sufficient efficacy to reduce polytherapy to improve seizure frequency in the normal (N) and mentally challenged (MC) population. Literature review for the device supports a 50-90% reduction of seizure frequency, decreased seizure severity and improvement in quality of life measures, alertness and memory. [Epilepsy & Behavior 2009 Oct; 16 (2 321-4) Epilepsy & Behavior 2001 Apr; 2 (2:129-134) Epilepsy & Behavior 2, 563-567 (2001)] Systematic drug reduction over time with continuation of individual patients on VNS long term has not been published. Reducing and tapering meds, eliminates drug interations, potential drug toxicity, lowers costs and helps cognition. Methods: A retrospective review of 540 charts was conducted on all patients implanted at Epilepsy Institute of NC. 220 qualified as Mentally Challenged (MC) by psychological testing (IQ 20-70). Implantation began in 1997. Efficacy was evaluated by seizure frequency, reduction of meds, VNS settings, adverse events, desire to continue VNS with guardian and patient consent. Medications were reduced after VNS settings were optimized for each patient. Clinic visits were conducted on a protocol. Patients were not surgical canidates & met FDA criteria for VNS stimulation. Polypharmacy taper was addressed after VNS threshold for that patient was reached (Approximately 1 Year). Educational meetings facilitated the process. We evaluated patients at years 1,2 and 6 for reduction of seizures. Efficacy is defined by percent seizure reduction after implantation. All drugs were kept in place until VNS was maximized. Results: From 1997-2007 we reviewed 540 charts retrospectivly. 220 mentally challenged having IQs of 20-70 ages 12-66 years. 52% reside in a residential facility, IQs 20-30. 48% have IQs of 50-70 and these patients lived in communities and came to our office. The remaining 320 patients have IQs of 80-120, age range 15-65 years & live with their family. The reduction of seizure frequency group N-year 1 68%/group MC 59%. Year 2 group N 70%/group MC 60%. Year 6 no significant change from year 2. Seizure reduction is based on baseline seizure frequency. 10% of MC group and 5% of N group could not be tapered off polypharmacy and suffered multiple relaspes. Most patients who were on 4 drugs and VNS at study entry are now on 2 drugs and VNS. Patients who were on 2 drugs and VNS are now on 1 drug and VNS. The study is ongoing. 20 patients relapsed and went to the ED. 80% were in the MC group. Conclusions: Both groups successfully tapered polypharmacy with support of VNS. Both groups had a similar response to VNS in seizure reduction. MC have more seizure clusters with relapses during the taper period. VNS facilitates polypharmacy reduction.