Neuropsychiatric outcomes in responsive neurostimulation: A single-center experience

Responsive neurostimulation (RNS) is an emerging technology for treating drug-resistant epilepsy (DRE). While seizure outcomes are well-documented, there is a paucity of literature evaluating the postoperative neurocognitive effects of RNS implantation in epilepsy patients utilizing the comprehensive neuropsychological tests often performed in pre-surgical evaluations. We compared pre- and post-RNS implantation neuropsychological evaluation results to elucidate neurocognitive changes.

We retrospectively reviewed charts of DRE patients who received RNS implants at our institution between 2017 and 2024 who underwent both pre- and post-operative neuropsychiatric evaluations. Evaluations included general abilities, attention, memory, language, visual-spatial/construction naming, executive function, and motor skills. Statistical significance was set at P < 0.05, and the threshold for clinically significant change was 2-3 for the American National Adult Reading Test (AMNART) premorbid estimate and 3-5 for all other measured neuropsychiatric outcomes.

We included 14 patients, and their mean age at RNS implantation was 39.1 years. The median seizure reduction in our cohort was 75%, with a 100% responder rate. The mean follow-up time for postoperative neuropsychiatric evaluation was 14.3 months. The vast majority of paradigms demonstrated no significant change. There was a small statistically and clinically significant reduction in the AMNART premorbid estimate (Mean change: -2.07, P = 0.0376) and verbal comprehension index (VCI) to normalized intelligence quotient scores (Mean change: -3.21, P = 0.0441). There was also a small statistically significant reduction in VCI Sum Scaled Scores (Mean change: -1.79, P = 0.0376) and Visual Spatial Construction Rey Figure Copy Raw Scores (Mean change: -2.19, P = 0.0249), but neither was clinically significant. Finally, there was a statistically significant but non-clinically significant increase in the Arithmetic Scaled Score (Mean change: ±1.21, P = 0.0055).

RNS was not associated with significant changes across multiple neuropsychology paradigms and may help attenuate the progressive neurocognitive decline often seen in DRE patients. Future research is needed to elucidate these trends further.