Brain‐responsive neurostimulation in patients with medically intractable seizures arising from eloquent and other neocortical areas
Authors: Jobst Barbara C. , Kapur Ritu , Barkley Gregory L. , Bazil Carl W. , Berg Michel J. , Bergey Gregory K. , Boggs Jane G. , Cash Sydney S. , Cole Andrew J. , Duchowny Michael S. , Duckrow Robert B. , Edwards Jonathan C. , Eisenschenk Stephan , Fessler A. James , Fountain Nathan B. , Geller Eric B. , Goldman Alica M. , Goodman Robert R. , Gross Robert E. , Gwinn Ryder P. , Heck Christianne , Herekar Aamr A. , Hirsch Lawrence J. , King‐Stephens David , Labar Douglas R. , Marsh W. R. , Meador Kimford J. , Miller Ian , Mizrahi Eli M. , Murro Anthony M. , Nair Dileep R. , Noe Katherine H. , Olejniczak Piotr W. , Park Yong D. , Rutecki Paul , Salanova Vicenta , Sheth Raj D. , Skidmore Christopher , Smith Michael C. , Spencer David C. , Srinivasan Shraddha , Tatum William , Van Ness Paul , Vossler David G. , Wharen Robert E. , Worrell Gregory A. , Yoshor Daniel , Zimmerman Richard S. , Skarpaas Tara L. , Morrell Martha J. 
Published: April 2017

Objective

Evaluate the seizure‐reduction response and safety of brain‐responsive stimulation in adults with medically intractable partial‐onset seizures of neocortical origin.

Methods

Patients with partial seizures of neocortical origin were identified from prospective clinical trials of a brain‐responsive neurostimulator (RNS System, NeuroPace). The seizure reduction over years 2–6 postimplantation was calculated by assessing the seizure frequency compared to a preimplantation baseline. Safety was assessed based on reported adverse events. Additional analyses considered safety and seizure reduction according to lobe and functional area (e.g., eloquent cortex) of seizure onset.

Results

There were 126 patients with seizures of neocortical onset. The average follow‐up was 6.1 implant years. The median percent seizure reduction was 70% in patients with frontal and parietal seizure onsets, 58% in those with temporal neocortical onsets, and 51% in those with multilobar onsets (last observation carried forward [LOCF] analysis). Twenty‐six percent of patients experienced at least one seizure‐free period of 6 months or longer and 14% experienced at least one seizure‐free period of 1 year or longer. Patients with lesions on magnetic resonance imaging (MRI; 77% reduction, LOCF) and those with normal MRI findings (45% reduction, LOCF) benefitted, although the treatment response was more robust in patients with an MRI lesion (p = 0.02, generalized estimating equation [GEE]). There were no differences in the seizure reduction in patients with and without prior epilepsy surgery or vagus nerve stimulation. Stimulation parameters used for treatment did not cause acute or chronic neurologic deficits, even in eloquent cortical areas. The rates of infection (0.017 per patient implant year) and perioperative hemorrhage (0.8%) were not greater than with other neurostimulation devices.

Significance

Brain‐responsive stimulation represents a safe and effective treatment option for patients with medically intractable epilepsy, including adults with seizures of neocortical onset, and those with onsets from eloquent cortex.