Abstracts

Rationale: This is a follow up of a ten year study with Vagus Nerve Stimulation (VNS) in refractory epilepsy of 640 patients at Epilepsy Institute of NC where VNS was implemented as adjunctive therapy to reduce seizure frequency in normal patients (N) 370 and mentally challenged patients (MC) 270. Literature review for the device supports 50-90% reduction of seizure frequency, decrease seizure severity and improvement of quality of life measures, & alertness and memory (Epilepsy, Behavior 2009 October 16 2 321-4). We ask the question does VNS sustain reduction in seizure frequency long term in this population? Methods: We maintained the original 540 patients (1997-2007) without loss in the base in follow up and increased this number by 100 patients and continue to follow for an additional 5 years. Total population is 640. 58% had normal IQs 42% were mentally challenged. these patients were office and institution based. We evaluated the patients at 1, 2, 5 and 10 years post implant. all drugs were fixed until VNS dosing was maximized. In the original population studied normal patients had a 60-68% reduction of seizure frequency compared to baseline and MC had a 58% reduction of seizure frequency compared to baseline. 10% of the population required replacement stimulators.Results: This study is retrospective/prospective originated in 2007. Children& adults included. Normal patients age 15-72 IQ 80-120. Mentally challenged ages12-68 IQ 20-70. Continous stimulation, replacement stimulators in both populations sustained seizure reduction. Normal patients sustained seizure reduction at 68-70% from baseline after the second year of implant and the mentally challenged had a seizure reduction of 59-60% well sustained after the second year of implant of VNS.Conclusions: Long term continuous stimulation with VNS sustains seizure reduction in both normal and mentally challenged patients. VNS is tolerable and effective in all age groups and types of epilepsy. Replacement generators are as effective for seizure control as original implants