VAGUS NERVE STIMULATION OUTCOME: 24-MONTH FOLLOW-UP
Abstract number :
3.264
Submission category :
Year :
2002
Submission ID :
3564
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Christine Dean. Neurology, Epilepsy Institute of North Carolina, Winston Salem, NC
OBJECTIVE: Participants in this discussion should understand the sustained increase in seizure frequency reduction shown through 24 months of vagus nerve stimulation (VNS) Therapy.
RATIONALE: Anti-epileptic drugs (AEDs) are reported most effective during the first 3 months taken, then effectiveness sometimes declines. This analysis charts the effectiveness of VNS Therapy over 24 months.
METHODS: The VNS patient outcome registry was queried for a constant cohort of patients with data available at baseline and after 3, 12, and 24 months of VNS therapy. Changes in seizure frequency and physician-assessed quality of life were reported for each interval.
RESULTS: As of February 2002, data were available for 465 patients at all 4 time points. Median seizure frequency reduction increased with time: 40.0% at 3 months, 52.0% at 12 months, and 62.5% at 24 months. Seizure reductions of 50% or more were reported for 46% patients at 3 months, 53% at 12 months, and 62% at 24 months; reductions of 75% or more were reported for 27% at 3 months, 34% at 12 months, and 38% at 24 months; No seizures were reported for 5% of the patients at 3 months, 6% at 12 months, and 7% at 24 months. By 24 months improvements in alertness were noted in 59% of patients, postictal period in 54%, seizure clustering in 46%, verbal skills in 37%, mood in 39%, achievement at work or school in 28%, and memory in 33%.
CONCLUSIONS: Unlike AEDs, for which effectiveness sometimes declines with time, median and proportional seizure frequency reduction for patients receiving VNS Therapy continued to increase over the 24 months of the analysis. The automatic delivery of VNS Therapy facilitates, if not ensures, patient compliance, an advantage over AEDs. Nonetheless, patient compliance alone cannot account for the steady improvement in seizure frequency reduction over time. Therefore, additional studies of long-term VNS Therapy outcome and possible physiologic changes should be undertaken.
(Disclosure: Grant - Cyberonics Inc., Honoraria - Cyberonics Inc.2000,2001,2002)