Chronic Subthreshold Cortical Stimulation for Paracentral Epilepsy-A Systematic Review

Area of Science:

• Neuroscience
• Epileptology
• Neuromodulation

Background:

• Drug-resistant epilepsy (DRE) in the paracentral region presents surgical challenges due to proximity to eloquent cortex.
• Existing neurostimulation options like VNS and DBS have limited efficacy for seizure freedom.
• Chronic subthreshold cortical stimulation (CSCS) is a novel approach targeting the epileptogenic zone.

Purpose of the Study:

• To evaluate the efficacy and safety of CSCS in patients with paracentral DRE.
• To assess stimulation parameters and neurologic outcomes associated with CSCS.
• To compare CSCS outcomes with other neurostimulation modalities.

Main Methods:

• Systematic literature review of PubMed/MEDLINE and EMBASE for studies on chronic electrical stimulation in the paracentral region.
• Inclusion of case reports, case series, and observational studies.
• Extraction of data on seizure outcomes, stimulation parameters, adverse events, quality of life, and neurologic effects; primary endpoints were ≥90% seizure reduction and seizure freedom.

Main Results:

• Six studies including 17 patients with a mean follow-up of 31.3 months were analyzed.
• Complete seizure freedom was achieved in 47% of patients, with an additional 35% experiencing ≥90% seizure reduction.
• Lesional epilepsy cases showed significantly higher seizure freedom rates (p=0.007); no major adverse events were reported; neurologic and QOL improvements were observed.

Conclusions:

• CSCS demonstrates promise for paracentral DRE, offering high seizure freedom rates, a favorable safety profile, and potential neuromodulatory benefits.
• Preliminary evidence suggests CSCS may be more effective than other neurostimulation modalities for paracentral epilepsy.
• Further prospective, controlled studies are needed to validate findings, optimize protocols, and refine patient selection.