Vagus Nerve Stimulation in Patients in Comatose State

Summary

Some patients with severe traumatic brain injury cannot respond at the bedside, yet about 1 in 4 may be aware but unable to show it - a hidden state called cognitive motor dissociation. This study tests a gentle, non-invasive treatment delivered through clips on the left ear that stimulates two nerves at once: the vagus nerve at the inner ear (taVNS) and the trigeminal nerve at the outer ear (taTNS). Each nerve has separately been shown to help people with disorders of consciousness recover, but they have not been combined before. All enrolled patients receive the stimulation for one hour a day, with continuous heart and oxygen monitoring and a pain-protection check used to keep the dose safe. The study measures recovery two ways: the Coma Recovery Scale-Revised (CRS-R), scored by clinicians, and SeeMe, an automated camera system that detects tiny command-driven movements the eye cannot see.

Detailed Description

This prospective, single-center, open-label, single-arm pilot study enrolls a subcohort of comatose TBI patients from the parent SeeMe study (NCT07560631) whose legally authorized representative consents to a stimulation addendum. Dual-site transcutaneous auricular nerve stimulation is delivered to the left ear: the vagal site (cymba conchae) targets the auricular branch of the vagus nerve, and the trigeminal site (outer ear) targets the auriculotemporal branch - each with distinct, optimized parameters. Mechanistically, vagal afferents project to the nucleus tractus solitarius and the ascending reticular activating system to promote arousal, while trigeminal afferents project via the spinal trigeminal nucleus to thalamus and cortex to enhance thalamocortical connectivity; the dual-site paradigm aims to drive the cortico-striatal-thalamic-cortical loop from two convergent directions. Baseline assessment captures CRS-R, GCS, vital signs, NCS-R, heart-rate variability, and EEG. Daily one-hour sessions include pre/post vitals, NCS-R-guided titration, continuous telemetry, ear-site inspection, and daily CRS-R. In parallel, the SeeMe computer-vision platform quantifies stimulus-evoked facial and hand movements. The course runs 7 consecutive days, extendable to 28 days. Findings will inform a future sham-controlled randomized trial and closed-loop integration with SeeMe.

Eligibility Criteria

Interventions