EpilepsiaResponsive Stimulation of the Thalamus for Idiopathic Generalized Epilepsy: Results of the Randomized Controlled NAUTILUS Trial Through 18 Months

⚠️ Small Study / Early Comparative Evidence

NAUTILUS evaluated responsive stimulation of the bilateral centromedian thalamus in 87 implanted patients aged 12 years or older with drug-resistant idiopathic generalized epilepsy and recurrent generalized tonic-clonic seizures. The randomized sham-controlled design addressed a population with limited procedural options because generalized seizure networks are not suitable for resection or ablation.

Clinical Considerations

• The trial met its primary safety endpoint, with a 6.9% serious adverse device-related event rate at 84 days.
• The prespecified primary effectiveness endpoint, time to second generalized tonic-clonic seizure, was not statistically significant.
• A post hoc mixed-effects model found greater 12-month GTCS reduction with earlier active stimulation versus delayed sham transition.
• At 18 months, median GTCS reduction reached 76.8%, with 62.5% responder rate and 40% GTCS-free at that timepoint.
• Days with any generalized seizure, absence seizures, and myoclonic seizures declined during stimulation periods, with sustained statistical reductions reported.
• Cognition, mood, and sleep measures showed no observed adverse stimulation effect through 18 months.
• Rescue benzodiazepine use on GTCS days decreased, and postictal recovery improved across most poststimulation intervals.
• Interpretation hinges on the split between a negative prespecified primary endpoint and supportive post hoc and open-label findings.

Practice Applications

• Recognize responsive thalamic stimulation as emerging evidence for drug-resistant idiopathic generalized epilepsy.
• Interpret efficacy cautiously because the primary effectiveness endpoint was not significant.
• Consider the safety profile alongside procedure-related risks, including infection, hemorrhage, and device complications.
• Monitor longer-term follow-up to clarify durability, subgroup response, and patient selection.
• Avoid framing post hoc seizure reductions as equivalent to prespecified primary endpoint success.
• Integrate seizure burden, rescue medication use, recovery time, and quality-of-life measures when evaluating future data.