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Updated: Apr 1, 2026
04:29
Vagus Nerve Stimulation As an Adjunctive Neurostimulation Tool in Treatment-resistant Depression
Published on: January 7, 2019
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Effects of vagus nerve stimulation on pupillary function.
Véronique Desbeaumes Jodoin1, Paul Lespérance2, Dang K Nguyen3
1Department of Psychology, UQAM, Canada; Department of Psychiatry, CHUM, Canada.
Summary
Vagus nerve stimulation (VNS) increases resting pupil diameter in patients with epilepsy or depression. This non-invasive measure offers insights into the central autonomic nervous system
Area of Science:
- Neuroscience
- Autonomic Nervous System
- Ophthalmology
Background:
- Chronic vagus nerve stimulation (VNS) is an established therapy for refractory epilepsy and depression.
- The vagus nerve influences central autonomic structures in the brainstem.
- Pupillary measures provide a non-invasive assessment of autonomic function.
Purpose of the Study:
- To investigate the impact of VNS on the human central autonomic nervous system.
- To evaluate changes in pupillary measures during VNS.
- To determine if VNS affects resting pupil diameter and light reflex.
Main Methods:
- Studied 21 patients (7 with depression, 14 with epilepsy) undergoing chronic VNS.
- Compared resting pupil size and light reflex during VNS ON and OFF periods.
- Utilized a 30s ON, 5 min OFF stimulation paradigm.
Main Results:
- VNS significantly increased resting pupil diameter compared to the OFF condition.
- No significant changes were observed in light reflex measures during VNS.
- No differences in pupillary responses were found between epilepsy and depression patient groups.
Conclusions:
- Clinically relevant VNS elevates resting pupil diameter.
- Pupillometry can serve as a biomarker for VNS effects on the central autonomic nervous system.
- VNS influences autonomic regulation, reflected in pupillary changes.
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