Related Experiment Video
Updated: Jun 25, 2026
04:04
Transauricular Vagus Nerve Stimulation and Electroencephalographic Assessment in Disorders of Consciousness
Published on: July 11, 2025
Does stimulus rate matter when performing somatosensory evoked potentials for coma patients?
Lawrence R Robinson1, Paula J Micklesen
1Department of Rehabilitation Medicine, University of Washington School of Medicine, P.O. Box 356380, Seattle, WA 98195, USA. lorenzo@u.washington.edu
Neurocritical Care
|February 20, 2009
Summary
Stimulation rate impacts median nerve somatosensory evoked potentials (SEPs) in comatose patients. About 1% showed absent SEPs at 3 Hz but present responses at 1 Hz, with most patients dying.
Area of Science:
- Neurophysiology
- Neurology
- Clinical Electrophysiology
Background:
- The influence of stimulation rate on cortical responses in comatose patients undergoing median nerve somatosensory evoked potentials (SEPs) is not well understood.
- This variability may impact the interpretation of SEPs for prognostication in coma.
Purpose of the Study:
- To determine the frequency of absent median nerve SEP responses at 3 Hz stimulation but present responses at 1 Hz in comatose patients.
- To report the outcomes of these specific patients.
Main Methods:
- Retrospective review of SEP recordings from 639 comatose patients over a 9-year period.
- All patients underwent median nerve stimulation at both 3 Hz and 1 Hz.
Main Results:
- Seven patients (approximately 1%) had absent bilateral SEP responses at 3 Hz but present responses at 1 Hz.
- Six of these seven patients died; one survived with moderate disability following traumatic brain injury.
Conclusions:
- The stimulation rate is a significant factor in the presence or absence of cortical responses in approximately 1% of comatose patients.
- Further research is needed to ascertain if these patients have distinct outcomes compared to those with absent responses at both stimulation rates.
