Vagus Nerve Stimulation AutoStim Feature, A Three-Year Study (4974)

Objective: To evaluate the relationship between AutoStim frequency and seizure control in patient with new detect and response VNS mode. Background: Up to 80% of epileptic patients experience tachycardia prior to onset of a seizure. The Automatic Stimulation Mode (AutoStim) feature of the Model 106 Vagus Nerve Stimulation (VNS) AspireSR Therapy System stimulates the left vagus nerve upon detecting tachycardia. Ample evidence demonstrates that seizure severity and duration are better controlled after starting VNS through its ability to detect and respond to tachycardia. We believe that the frequency of AutoStims will decrease over time when seizures are better controlled. Design/Methods: Data was collected retrospectively from EPIC in patients with epilepsy who had VNS AspireSR implanted at UTMB between 2015–2018. VNS start date, seizure type, burden of seizure before VNS, and burden of seizure and VNS AutoStim frequency at different time points after the VNS was started was collected. Results: In 27 patients with VNS placement, 88%, 7.4%, 26%, 14.8%, 11%, 22% patients have generalized tonic clonic seizure (GTC), simple partial seizure, complex partial seizure, unspecified partial seizure, atonic seizure and absence seizure respectively. Seizure frequency was reduced by an average of 56%, 51%, 74%, 66%, and 46% at 3 months, 6 months, 1 year, 1.5 years, and 3 years after VNS implantation, respectively. 93% of patients reported that VNS had decreased their seizure severity. There was no significant difference in number of AutoStim pulses triggered at 3 months, 6 months, 1 year, 1.5 year and 3 year after VNS implantation. Conclusions: VNS has been shown to be effective in reducing the number of seizures in patients with partial and secondarily generalized seizures. Though it is thought that the number of AutoStim pulses would decrease over time, our study showed there was no significant difference in the frequency of AutoStim pulses generated. Disclosure: Dr. Rai has nothing to disclose. Ms. Curtis has nothing to disclose.