Prospective Long-term Seizure Outcomes in Medically-resistant Focal Epilepsy Subjects with Neuromodulation Devices
Gabriel Biondo1, Ojas Potnis2, Rachel Sukonnik3, Caitlin Grzeskowiak4, Gary Cutter5, Jacqueline French6
1Department of Biological Sciences, University of Notre Dame, 2School of Medicine, School of Engineering, Enmed MD/ME program, Texas A&M, 3Medical and Molecular Science Department, University of Delaware, 4Epilepsy Foundation of America, 5University of Alabama At Birmingham, 6NYU Comprehensive Epilepsy Ctr
Objective:

Evaluate the trajectory of epilepsy in treatment resistant patients in the presence or absence of devices.

Background:
Several long-term open label trials of devices to treat epilepsy (vagus Nerve Stimulator (VNS), Responsive Neurostimulator (RNS), Deep Brain Stimulator (DBS) have demonstrated a reduction in seizures over time, suggesting “disease modification”, but it is unknown if seizure trajectories differ in patients with or without devices. We evaluated trajectories in patients in the Human Epilepsy Project 2 (HEP2) with and without devices.
Design/Methods:

HEP2 subjects met the following qualifications: experienced failure of adequate trials of 4 anti-seizure medicines (ASMs), having ≥2 focal seizures per month for 3 months before enrollment, and receiving ≥1 ASM at baseline.  Seizure frequency was collected monthly.  Progress and activity of neuromodulation devices were recorded at each monthly check-in and provided in medical records.

Results:

35 / 146 subjects had a device (22 at baseline; 14 implanted during observational period).  5 subjects had multiple devices and 2 had a device removed during the observational period (1 was a replacement).  VNS=22, RNS=11, DBS=6, other=1.  The median time in all subjects with devices from device implantation to the end of the observational period was 1210 days.

 

There were no significant differences in seizure trajectories among different devices or between subjects with and without devices.   Subjects showed a consistent reduction trend of about 1 seizure per month during the observational period.  There was no significant variation in seizure frequency reduction with respect to device type, p=0.9895.  The average monthly seizure frequency post-implantation was slightly higher (15.6) for those with devices implanted during the observational period compared to those without devices at baseline (15.0); however, no statistically significant differences were found between the two groups. 
Conclusions:

In patients with medically resistant focal epilepsy, neuromodulation devices did not change seizure trajectory over time compared to subjects without devices.  

10.1212/WNL.0000000000205033