Assessing an fMRI-guided titration paradigm for microburst VNS therapy

Area of Science:

• Neuroscience
• Medical Technology
• Epilepsy Research

Background:

• Vagus nerve stimulation (VNS) is effective for epilepsy, but personalized dosing requires better physiological monitoring.
• Cortical and subcortical physiological engagement could optimize VNS therapy for people with epilepsy (PwE).

Purpose of the Study:

• To assess the feasibility and safety of fMRI-guided titration for VNS in people with drug-resistant epilepsy (DRE).
• To explore thalamic BOLD response as a biomarker for VNS therapeutic engagement and seizure response.

Main Methods:

• A feasibility study enrolled people with DRE using investigational microburst VNS.
• fMRI-guided titration determined optimal VNS settings over 6 months, targeting maximal thalamic BOLD response.
• Thirty-two participants were implanted, with 31 completing 6-month follow-up and fMRI assessments.

Main Results:

• Significant VNS-evoked thalamic BOLD responses were observed in all participants.
• Participants showing consistent thalamic BOLD signal increases were more likely to respond to VNS.
• Median seizure frequency reduction was 42.6% at 6 months, with no MRI-related safety issues.

Conclusions:

• fMRI-guided VNS titration is feasible and safe in PwE using investigational devices.
• The thalamic BOLD signal biomarker, while variable, correlated with seizure response and could be visualized early.
• This approach shows promise for personalized VNS therapy, though the biomarker requires refinement.