title: Differential neuropsychological outcomes following targeted responsive neurostimulation for partial-onset epilepsy.
abstract: OBJECTIVE
  Responsive neurostimulation decreases the frequency of disabling seizures when used as an adjunctive therapy in patients with medically refractory partial-onset seizures. The effect of long-term responsive neurostimulation on neuropsychological performance has not yet been established.
  
  
  METHODS
  Neuropsychological data were collected from subjects participating in the open-label arm of a randomized controlled trial of responsive neurostimulation with the RNS(®) System. Primary cognitive outcomes were the Boston Naming Test (BNT) and Rey Auditory Verbal Learning (AVLT) test. Neuropsychological performance was evaluated at baseline and again following 1 and 2 years of RNS System treatment. Follow-up analyses were conducted in patients with seizure onset restricted to either the mesial temporal lobe or neocortex.
  
  
  RESULTS
  No significant cognitive declines were observed for any neuropsychological measure through 2 years. When examined as a function of seizure onset region, a double dissociation was found, with significant improvement in naming across all patients (p < 0.0001), and for patients with neocortical seizure onsets (p < 0.0001) but not in patients with mesial temporal lobe (MTL) seizure onsets (p = 0.679). In contrast, a significant improvement in verbal learning was observed across all patients (p = 0.03), and for patients with MTL seizure onsets (p = 0.005) but not for patients with neocortical onsets (p = 0.403).
  
  
  CONCLUSIONS
  Treatment with the RNS System is not associated with cognitive decline when tested through 2 years. In fact, there were small but significant beneficial treatment effects on naming in patients with neocortical onsets and modest improvements in verbal learning for patients with seizure onsets in MTL structures. These results suggest that there are modest cognitive improvements in some domains that vary as a function of the region from which seizures arise.
authors.affiliation: Departments of Neurology and Pediatrics, Emory University, Atlanta, Georgia, U.S.A.
authors.forename: David W
authors.initials: DW
authors.lastname: Loring
authors.affiliation: Clinical Research, NeuroPace, Inc., Mountain View, California, U.S.A.
authors.forename: Ritu
authors.initials: R
authors.lastname: Kapur
authors.affiliation: Department of Neurology and Neurological Sciences, Stanford University Medical Center, Stanford, California, U.S.A.
authors.forename: Kimford J
authors.initials: KJ
authors.lastname: Meador
authors.affiliation: Clinical Research, NeuroPace, Inc., Mountain View, California, U.S.A.|Department of Neurology and Neurological Sciences, Stanford University Medical Center, Stanford, California, U.S.A.
authors.forename: Martha J
authors.initials: MJ
authors.lastname: Morrell
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000295:instrumentation / Q000379:methods*; D004311:Double-Blind Method; D004828:Epilepsies, Partial / Q000175:diagnosis / Q000523:psychology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D058542:Implantable Neurostimulators; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D016896:Treatment Outcome; D055815:Young Adult
keywords: Brain stimulation; Epilepsy; Memory; Naming