Abstracts

Rationale: Cardiac-based closed-loop vagus nerve stimulation is now widely available. It is supposed to delivered the regular conventional cyclic stimulation and  extra stimulation cycles based on relative cardiac frequency increase. We studied how much extra stimulation is delivered in children with Lennox-Gastaut syndrome by a closed-loop VNS device. Methods: Ten children with Lennox-Gastaut syndrome submitted to implantation of Livanovas` Aspire device were studied. The device closed-loop paradigm was set to recording sensitivity level 2 and to a 20% increase in cardiac frequency  for extra stimuli delivery. The proportion of regular/extra cycles was evaluated every 2 weeks. Data from the last 3 months of stimulation were recorded. Results: The closed-loop-driven extra cycles comprised 14-57% (mean= 23%) of the total number of cycles delivered. Seizure frequency ranged from 4 to 21 per day (mean=7.3). Conclusions: Children receiving closed-loop VNS received much more stimulation then those receiving only standard open scheduled stimulation. The number of extra cycles is much higher then the expected seizure frequency, suggesting many false positive detections occurred in this patient population using the above mentioned paradigm. Adequate clinical follow-up would be able to clarify if those receiving more stimulation would have a better outcome regarding seizures or cognitive function. Funding: None