Effects of Transcutaneous Vagal Nerve Stimulation on Post-Surgical Return to Consciousness, Delirium, and Depression (tVNS)

May 26, 2026 updated by: Charles Hogue, Northwestern University
This study will examine whether noninvasive, transcutaneous vagal nerve stimulation (tcVNS) can help restore consciousness in patients in the operating room and the Post Anesthesia Care Unit (PACU). The study will also investigate if tcVNS can expedite discharge from the PACU and examine whether tcVNS administerd in the PACU helps reduce delirium and depression after surgery. The study will also evaluate whether tcVNS speeds cognitive recovery from emergence of anesthesia and surgery.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Recruiting
        • Northwestern University Feinberg School of Medicine
        • Contact:
        • Contact:
        • Principal Investigator:
          • Charles Hogue, MD
        • Sub-Investigator:
          • Ravindra A Gupta, MD
        • Sub-Investigator:
          • John Bebawy, MD
        • Sub-Investigator:
          • Eyal Kimchi, MD, PhD
        • Sub-Investigator:
          • Jacqueline Morano, MD
        • Sub-Investigator:
          • Jamie Uejima, MD
        • Sub-Investigator:
          • Kimberly Klafta, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Aged > 18 years of age
  2. Patients undergoing lumbar surgery for degenerative disc disease or spinal stenosis involving two or more levels
  3. Montreal Cognitive Assessment (MoCA) score ≥ 18 - accept mild
  4. Ability to use a keyboard
  5. Able to understand and communicate in English
  6. Be able to consent independently
  7. Women of child-bearing age must be comfortable confirming a negative pregnancy prior to participating in the study.
  8. Must not be involved in any other research intervention study testing neurobehavioral functioning

Exclusion Criteria:

  1. Age < 18 years of age
  2. History of vagotomy (cutting the vagus nerve)
  3. History of bradycardia, heart block, prolonged QT syndrome, brugada syndrome, heart failure with ejection fraction less than 35% and/or New York Heart Association symptoms
  4. MoCA < 18
  5. History of seizure disorder or intracranial hemorrhage
  6. Patients with carotid stenosis
  7. Patients with aneurysms
  8. Other neurological diagnoses or a diagnosis of severe psychiatric disorder (e.g., psychosis) or a reported childhood learning disability
  9. Pregnancy, breastfeeding
  10. Active addiction history
  11. ECG adhesive allergy
  12. Severe aphasia, preventing subject from understanding the protocol and giving written consent
  13. Patients will be excluded postoperatively if there is neck swelling at the proposed site of left tcVNS.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: tcVNS Stimulation (Intervention)
Transcutaneous vagal nerve stimulation (tcVNS)
Device: Transcutaneous vagal nerve stimulation
The tcVNS device utilized in this study is not an implanted device, but rather is solely operated outside of the body by affixing it around the patient's ear. The device delivers stimulation of the vagus nerve at designated intensity, interval, and frequency.
Sham Comparator: Sham tcVNS stimulation (Control)
Sham transcutaneous vagal nerve stimulation (Sham tcVNS)
Device: Sham (No Treatment)
The stimulator is flipped upside down so that the participant does not receive stimulation of the vagal nerve.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Aim 1: Primary Endpoint 1: Determine if administering auricular tcVNS enhances the speed of recovery of anesthesia.
Time Frame: 24 Hours
Time in minutes to a Patient State Index (PSI) (Sedline Sedation Monitor) score of 85. The PSI is a quantitative score derived from 4 channel EEG monitoring of the frontal and prefrontal cortex for assessing level of consciousnes during sedation and general anesthesia. The score ranges from 0 (EEG supression) -100 (fully awake). A PSI range of 25-50 indicates optimal hypnotic state for general anesthesia
24 Hours
Aim1:Primary Endpoint 2 : Richmond Agitation Sedation Scale (RASS Score)
Time Frame: 1 Hour
The Richmond Agitation-Sedation Scale (RASS) is a 10-point validated scale used to measure patient sedation levels in post-anesthesia care unit, ranging from +4 (combative) to -5 (unarousable). A score of 0 is "alert and calm".Measured on arrival to PACU then at 10,15,30,45,60 minutes after admission to PACU.
1 Hour
Aim 2: Primary Endpoint 1: Post Anesthesia Care Unit Discharge (PACU)
Time Frame: 3 Hours
Admission time to the PACU to discharge from PACU in minutes elapsed.
3 Hours
Aim 2: Primary Endpoint 2: Discharge from Hospital
Time Frame: From PACU discharge (average of two hours post-surgical end time) to study completion (average of two days)
Time from Post Anesthesia Care Unit discharge to discharge from the hospital in days/minutes
From PACU discharge (average of two hours post-surgical end time) to study completion (average of two days)
Aim 3: Primary Endpoint 1: Post Anesthesia Care Unit delirium
Time Frame: From PACU arrival to one hour post-PACU arrival
Comparison between active and sham tcVNS on delirium scores in the PACU at 30, 45 and 60 minutes after admission to the PACU. The 3D Confusion Assessment Method (3D CAM) will be administered at 30, 45 and 60 minutes after admission to PACU. The 3D CAM diagnostic tool scores delirium based on four core features, where Feature 1 (Acute Change) AND Feature 2 (Inattention) MUST be present, plus either Feature 3 (Disorganized Thinking) or Feature 4 (Altered Consciousness). It offers a severity score (3D-CAM-S) ranging from 0-20, with higher scores indicating more severe symptoms (0/20 low 20/20 high
From PACU arrival to one hour post-PACU arrival
Aim 3: Primary Endpoint 1a: Post Anesthesia Care Delirium
Time Frame: 30 Days after discharge
Delirium scores 30 days after discharge from the hospital. The 3D Confusion Assessment Method (3D CAM) will be administered 30 days after discharge from the hospital. The 3D CAM diagnostic tool scores delirium based on four core features, where Feature 1 (Acute Change) AND Feature 2 (Inattention) MUST be present, plus either Feature 3 (Disorganized Thinking) or Feature 4 (Altered Consciousness). It offers a severity score (3D-CAM-S) ranging from 0-20, with higher scores indicating more severe symptoms (0/20 low 20/20 high
30 Days after discharge
Aim3:Primary Endpoint 1b: PHQ-9
Time Frame: 30 days
The Patient Health Questionnaire Nine (PHQ-9) is a 9-question survey used to measure patient depression potential, ranging 1-27 (1 low possibility of depression to 27 highest potential for depression. Tested at baseline, post operative day 1 and 30 days post discharge from hospital.
30 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Aim 3: Secondary Endpoint 1:EEG Monitoring Data
Time Frame: From pre-surgical EEG placement (i.e. approximately 30 minutes before surgery) through study completion (an average of 2 days)
Continuous EEG monitoring data to be evaluated for patterns associated with delirium (polymorphiic delta waves, generalized slowing quantified as delta range vs alpha range power
From pre-surgical EEG placement (i.e. approximately 30 minutes before surgery) through study completion (an average of 2 days)
The Montreal Cognitive Assessment (MoCA) evaluations
Time Frame: 48 hours
The MoCA includes measures of memory recll, visuospatial processing, executive functions, attention, language, abstract reasoning and orientation to time and place. Administered baseline and post operative day 2. 0-30 point scale, 26 and above is normal, 18-25 mild cognitive dysfunction, 10-17 is moderate dysfunction and 0-10 is severe dysfunction.
48 hours
SF-36 Survey
Time Frame: 30 days
The 36-Item Short Form Survey (SF-36) is a self-reported patient outcome measure that assesses physical and mental health across eight domains, including functioning, pain, and vitality. Score ranges from 0 low to 100 high. The higher the score the better the overall health. Administered at baseline and 30 days after discharge.
30 days
Neuro Qol Cognition Function Short Form
Time Frame: 30 Days
This is a brief self-report tool used to measure perceived difficulties in everyday cognitive tasks. It is a portion of of the Quality of Life in Neurological Disorders (Neuro-QoL). he short form uses T-scores, which standardize results against a reference population (typically the U.S. general population).There are 8 questions. A T-score of 50 represents the average for the reference population. A high score indicates better perceived cognitive function. Completed at baseline and 30 days.
30 Days
Neuro- QOL
Time Frame: 30 Days
Neuro-QoL(Quality of Life in Neurological Disorders) is a measurement system that evaluates and monitors the physical, mental, and social effects experienced by adults who may have neurological conditions. Tested at baseline and 30 days.
30 Days
DRS-R-98
Time Frame: 48 hours
The Delirium Rating Scale (DRS-R-98) is a tool for assessing symptom severity and diagnosing delirium in clinical settings. This sixteen-item scale in a thirteen-item severity section and three diagnostic items, tracking changes over a twenty-four-hour period. The 16-item, clinician-rated tool used to diagnose and measure the severity of delirium. It consists of 13 severity items (scored 0-3) and 3 diagnostic items (scored 0-2 or 0-3), with a maximum total score of 46. Higher scores indicate more severe delirium, with scores of15 or greater than or greater than 17.5 often indicating delirium. Assessed at Day 1 and day 2 post operative.
48 hours
DigitSpan Test
Time Frame: 48 Hours
Digit Span test measures auditory short-term memory and working memory capacity by asking participants to repeat sequences of digits in forward, reversed, or ordered sequences. It is used to measure cognitive processing, attention, and executive function, usually contains 5-9 digits. scoring typically awards one point for each correctly repeated sequence. Performed post operative day 1and 2.
48 Hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Northwestern University

Investigators

  • Principal Investigator: Charles Hogue, MD, Northwestern University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 23, 2026

Primary Completion (Estimated)

December 31, 2028

Study Completion (Estimated)

May 31, 2029

Study Registration Dates

First Submitted

May 13, 2026

First Submitted That Met QC Criteria

May 26, 2026

First Posted (Actual)

May 28, 2026

Study Record Updates

Last Update Posted (Actual)

May 28, 2026

Last Update Submitted That Met QC Criteria

May 26, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STU00223307

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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