Abstracts

Rationale: Anti-epileptic neuromodulation therapies are traditionally introduced later in a patient’s epilepsy treatment journey, coinciding with a failure of two or more anti-epileptic drugs (AEDs). Interestingly, few studies have examined the impact of introducing neuromodulation earlier in this journey; possibly before patients are classically defined as "drug-resistant." Early intervention of vagus nerve stimulation (VNS) is shown to significantly decrease seizure burden in patients within five years of their epilepsy diagnosis, or who had tried four or fewer AEDs compared to patients that were intervened later.

Methods: To gain a better understanding of introducing VNS earlier on seizure burden and quality of life outcomes, this single-center retrospective study compared the therapeutic efficacy of early versus late introduction of VNS therapy. This study retrospectively reviewed epilepsy monitoring unit and follow-up data from adult patients with VNS at Inova Fairfax Hospital from January 2016-June 2021. A total of 87 patients were include in this retrospective study and we identified two patient groups: a) “early VNS” intervention (≤2 ASMs at the time of implant) and b) “late VNS” intervention ( >2 ASMs at the time of implant). We also classified patients into early versus late based on the number of years since epilepsy onset (less than or greater than 5 years). However, the data analysis is ongoing. Follow-up data was taken at 6 months-5 years post-VNS implant. The primary outcome measure was change in seizure frequency from baseline (prior to) to post-VNS implant, and secondary outcome measures include patient-reported changes in seizure episode intensity, recovery time, seizure length, and number of emergency room visits (6 months post-implant), alertness, communication, mood, and memory changes.

Results: The “early VNS” patients were shown to have a significant reduction in seizure frequency compared to “late VNS” patients (p=0.021). There was also a significant reduction in seizure episode intensity (p=0.005) and emergency room visits at 6 months post-implant (p=0.025). There were no significant changes in the other outcomes assessed.

Conclusions: Similar results were reported by our group in a 2020 AES abstract and poster (51 patients), but this study reports results with an increased sample size (more than 87 patients). This is the first study to demonstrate that earlier intervention with VNS yields significant therapeutic benefit and improvements in quality of life. We hypothesize that neuromodulation intervention at earlier onset of epilepsy is able to better decrease seizure activity in the brain than later intervention. Collectively, these results challenge the use of VNS only as a "second-line" therapeutic intervention and therefore should be considered a promising treatment option when introduced earlier in a patient’s epilepsy journey.

Funding: Please list any funding that was received in support of this abstract.: none.