taVNS During Exercise and Recovery in Chronic Spinal Cord Injury (taVNS-HRV-SCI)

April 8, 2026 updated by: Maria Cristina Nicolau Llobera, University of the Balearic Islands

Transcutaneous Auricular Vagus Nerve Stimulation Modulates Autonomic Dynamics During Exercise and Recovery in Chronic Spinal Cord Injury

This study investigates the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on autonomic cardiovascular regulation during exercise and recovery in individuals with chronic spinal cord injury (SCI). Participants undergo two experimental conditions (active taVNS and sham stimulation) in a randomized crossover design while performing a standardized exercise protocol.

Heart rate variability (HRV) is used as a non-invasive biomarker to assess autonomic nervous system dynamics across different phases (baseline, exercise, and recovery). The aim is to characterize physiological responses to neuromodulation and explore whether taVNS modulates autonomic adaptability in this population.

This is a mechanistic physiological study designed to improve the understanding of autonomic regulation in SCI and to explore potential biomarkers of response to neuromodulation.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Spinal cord injury (SCI) is associated with significant impairments in autonomic nervous system function, particularly affecting cardiovascular regulation. These alterations reduce physiological adaptability to internal and external stressors and may contribute to increased cardiovascular risk.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique that has been proposed as a potential tool to influence autonomic function. However, its effects on dynamic autonomic regulation during physiological stress, such as exercise, remain insufficiently characterized in individuals with SCI.

The present study is a randomized, controlled, crossover experimental protocol designed to investigate the acute effects of taVNS on autonomic cardiovascular dynamics during a structured exercise and recovery paradigm. Participants with chronic SCI are exposed to two conditions: active taVNS and sham stimulation, applied in a randomized order.

Each experimental session includes three phases: baseline (rest), exercise (submaximal effort), and recovery. Continuous electrocardiographic recordings are obtained to derive heart rate variability (HRV) metrics. Both linear (time and frequency domain) and non-linear analyses are performed to characterize autonomic regulation and system dynamics.

The primary objective is to evaluate whether taVNS modulates autonomic responsiveness and adaptability across different physiological states. Secondary objectives include the exploration of HRV-derived biomarkers that may reflect autonomic complexity and the identification of response patterns to neuromodulation.

This study is not designed to evaluate clinical efficacy or therapeutic outcomes but to provide mechanistic insight into autonomic regulation and neuromodulation effects in SCI. The results may contribute to the development of personalized approaches in neurorehabilitation and autonomic monitoring.

Study Type

Interventional

Enrollment (Actual)

35

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 Locations

  • Spain
    • Balearic Islands
      • Palma de Mallorca, Balearic Islands, Spain, 07122
        • University of the Balearic Islands

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:

  • Adults (≥18 years) with chronic spinal cord injury
  • Medically stable condition
  • Ability to perform the exercise protocol
  • Ability to provide informed consent

Exclusion Criteria:

  • Acute spinal cord injury
  • Severe cardiovascular or respiratory instability
  • Use of medications significantly affecting autonomic function
  • Skin lesions or contraindications to transcutaneous stimulation
  • Cognitive impairment preventing protocol compliance

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active taVNS
Transcutaneous auricular vagus nerve stimulation applied during the experimental protocol.
Device: Transcutaneous Auricular Vagus Nerve Stimulation
Non-invasive electrical stimulation applied to the auricular branch of the vagus nerve using transcutaneous electrodes during the experimental protocol.
Sham Comparator: Sham Stimulation
Sham stimulation applied under identical experimental conditions without effective vagus nerve activation.
Device: Sham Stimulation
Sham stimulation delivered with identical device setup but without effective activation of the vagus nerve.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
DFA α2
Time Frame: Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
Detrended fluctuation analysis (α2) derived from RR intervals to assess long-term fractal scaling properties of heart rate variability. RR intervals are recorded continuously and analyzed offline. Data are processed using 5-minute overlapping windows. The value reported at each specific time point represents the calculation for the preceding 5-minute window to characterize autonomic regulation across the session.
Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
RMSSD (ms)
Time Frame: Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
Root mean square of successive differences (RMSSD) of RR intervals to assess short-term heart rate variability and parasympathetic activity. RR intervals are recorded continuously and analyzed offline. Data are processed using 5-minute overlapping windows. The value reported at each time point represents the calculation for the preceding 5-minute window..
Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
HF power (ms²)
Time Frame: Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
High-frequency (HF) power (0.15-0.40 Hz) derived from RR intervals to assess parasympathetic modulation. Spectral analysis is performed using standard frequency-domain methods. Data are processed using 5-minute overlapping windows. Each reported value corresponds to the preceding 5-minute window at the specified time point.
Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
LF power (ms²)
Time Frame: Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
Low-frequency (LF) power (0.04-0.15 Hz) derived from RR intervals to assess combined autonomic modulation. Frequency-domain analysis is performed after preprocessing of RR interval data. Data are processed using 5-minute overlapping windows. Each reported value corresponds to the preceding 5-minute window at the specified time point.
Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
SD1 (ms)
Time Frame: Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.
SD1 derived from the Poincaré plot of RR intervals, representing short-term beat-to-beat variability. RR intervals are recorded continuously and analyzed offline. Data are processed using 5-minute overlapping windows. Each reported value corresponds to the preceding 5-minute window at the specified time point.
Baseline (last 5 minutes of rest), 10, 15, 20, 25, 30, 35, and 40 minutes.

Collaborators and Investigators

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

Sponsor

University of the Balearic Islands

Collaborators

Health Research Institute of the Balearic Islands (IdISBa, Spain)
University of the Balearic Islands - Institute for Health Sciences Research (UNICS)

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)

October 31, 2024

Primary Completion (Actual)

October 31, 2024

Study Completion (Actual)

October 31, 2024

Study Registration Dates

First Submitted

March 17, 2026

First Submitted That Met QC Criteria

April 8, 2026

First Posted (Actual)

April 13, 2026

Study Record Updates

Last Update Posted (Actual)

April 13, 2026

Last Update Submitted That Met QC Criteria

April 8, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • UIB-taVNS-SCI-2024
  • 19CER24 (Other Identifier: Research Ethics Committee of the University of the Balearic Islands (UIB))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared due to privacy and ethical considerations. Aggregated data may be available upon reasonable request.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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