Responsive Neuro-Stimulation versus Deep Brain Stimulation in Drug Resistant Focal Epilepsy: A Systematic Review
Authors: Khorkhash Khaled Mohammed Mahmoud , El-Shazly Ayman Abd-El-Ra'ouf , Ibrahim Fayed Zeiad Youssry , Hefny Sameh Mohamed 
Published: November 2024

Abstract

Background
Epilepsy, a common neurological disorder affecting approximately 70 million people worldwide, poses significant challenges due to its comorbidities, impact on quality of life, and increased mortality, particularly among individuals with drug-resistant epilepsy (DRE). This meta-analysis aimed to compare the efficacy, safety, and long-term outcomes of two neuromodulation techniques, Responsive Neurostimulation (RNS) and Deep Brain Stimulation (DBS), for the treatment of drug-resistant focal epilepsy.

Objective
To compare the efficacy of RNS and DBS in reducing seizure frequency and improving seizure-related quality of life in patients with drug-resistant focal epilepsy and safety profile of RNS and DBS including adverse events and complications in the treatment of drug-resistant focal epilepsy. This will be done through a systematic review of literature addressing this research question.

Methods
All studies from Jan 2000 – Dec 2023 including randomized or non-randomized clinical trials, prospective or retrospective observational cohort studies, case control studies and case series of 6 or more cases that address the research question were collected. Systematic reviews, technical notes, letters, comments, duplicates, unavailable full texts or abstract-only articles were excluded.

Results
RNS and DBS in reducing seizure frequency over a follow-up period ranging from one to three years. At one year follow-up, RNS demonstrated a mean seizure reduction of 66.3%, compared to 58.4% with DBS. Similarly, at two and three years follow-up, RNS maintained higher mean seizure reduction percentages compared to DBS, although the differences were not statistically significant. These findings suggest that both RNS and DBS are effective in reducing seizure frequency in patients with drug-resistant focal epilepsy, with RNS potentially offering a slight advantage in terms of seizure reduction. RNS and DBS were associated with adverse events, although the incidence and severity varied between the two modalities. RNS demonstrated a relatively lower incidence of adverse events, with infections being the most common complication. On the other hand, DBS had a higher incidence of adverse events, including infections, DBS was associated with cognitive side effects (memory impairment in 27.3% of people at 5 years) and it has been suggested that RNS might have positive effects on cognition in the long term.

Conclusion
While RNS and DBS show promising efficacy in reducing seizure frequency, RNS appears to have a slightly favorable safety profile with potentially fewer adverse events compared to DBS. However, further research is warranted to better understand the long-term efficacy, safety, and impact on neuropsychological outcomes and quality of life for both modalities. Clinicians should carefully consider individual patient characteristics and preferences when selecting between RNS and DBS for the management of epilepsy.