We aimed to study the proportion of patients with DRE (with pre-existing VNS device), who show improvement of at least one class in McHugh seizure outcome classification at last follow up after generator replacement with cardiac-based VNS device.

In the past decade, a closed loop VNS device employing a cardiac-based seizure detection algorithm (AspireSR^®) has become available, allowing detection of ictal tachycardia as a surrogate marker for seizure. There is no published literature exploring the effect of battery replacement with AspireSR^® on the seizure frequency in children.

The study population was comprised of 15 patients. The mean age at seizure onset was 2.7 years old, with mean age of initial VNS placement being 10.1 years and mean age of replacement with cardiac-based VNS being 14.9 years of age. 3/15 patients had reported status epilepticus prior to initial VNS insertion, and none reported episodes following insertion. At last follow-up on initial VNS, the McHugh seizure outcomes were I (1/15), II (6/15), III (7/15), and V (1/15). The mean follow-up period within our cohort post-cardiac-based VNS placement was 0.9 years (SD 0.6 years). The McHugh seizure outcomes at last follow up after cardiac-based VNS were II (4/13), III (5/13), and V (4/13), with 2 patients showing at least one class improvement.

We note that the majority of our patients maintains their seizure control following replacement with cardiac-based VNS with a few showing improvement. Future plans include continuing to follow this cohort over time, as well as to obtain the data from our collaborator sites.