Seizure improvement following vagus nerve stimulator (VNS) battery change with cardiac-based seizure detection automatic stimulation (AutoStim): early experience in a regional paediatric unit.

PURPOSE

The recent VNS models (AspireSR® Model 106, SenTiva™ Model 1000 (VNS Therapy®, LivaNova)) include a new function of cardiac-based seizure detection (CBSD) automatic stimulation, known as 'AutoStim'. This algorithm uses tachycardia as a proxy to a seizure, and the battery delivers a closed-loop electrical current in addition to its programmed stimulation. This function leads to further seizure reduction in adults, but this advantage has not been reported in the paediatric population. This study aims to investigate whether battery change with AutoStim leads to further seizure reduction in children.

METHODS

This observational study included the first 10 cases of VNS battery change from non-AutoStim to AutoStim function. During the battery change operation, the new VNS was switched on, with the same normal and magnet mode settings as the previous VNS. The AutoStim mode was activated at the same time. Data on seizure burden were collected at 3 time points: (1) before the first VNS insertion, (2) before battery replacement (post-1st VNS) and (3) 12 months post-battery change (post-AutoStim). The net effect of AutoStim, the only changed parameter, was evaluated by comparing the seizure burden prior to and 12 months following battery change in each child.

RESULTS

The seizure reduction improved significantly from 60 to 83% following battery change with AutoStim. Categorising the outcome according the McHugh classification, children achieving class I and II outcome (≥ 50% seizure reduction) improved from 70 to 90%.

CONCLUSION

This is the first study to demonstrate the additional efficacy of AutoStim in children treated with VNS.