Effects of Non-invasive Brain Stimulation on Pain Avoidance Behavior in Chronic Pain Patients

August 26, 2026 updated by: Raghavan Gopalakrishnan, The Cleveland Clinic

Alpha tACS and Pain Avoidance Behavior in Chronic Pain Patients

Pain avoidance helps with survival. However, chronic pain patients often avoid valued life activities fearing onset or exacerbation of pain. Hence, pain avoidance no longer protects, but reduces quality of life. The goal of this clinical trial is to learn if non-invasive brain stimulation technique called transcranial alternating current stimulation (tACS) impact pain avoidance behavior in chronic pain patients. tACS is a way to gently stimulate the brain using a small, portable device. It sends an extremely weak, continuous alternating current through the scalp. Participants will either get real tACS or a fake (sham) version. Real tACS will stimulate the brain in the alpha frequency (8-12 Hz) which has been found to influence pain avoidance behavior, whereas sham tACS will stimulate the brain in a different frequency that is not known to influence avoidance behavior. The main questions it aims to answer are:

Does tACS alter the way chronic pain patients confront pain in terms of avoidance behavior? How does tACS impact brain signals related to pain avoidance behavior?

Participants will:

  1. fill out self-administered questionnaires asking about their medication use, personality and temperament, mood, including anxiety and depression, current pain level, and any disability you have due to your pain.
  2. perform of a pain avoidance task before, during and after 'real' tACS or 'sham' tACS. They may also be asked to stay quiet before, during and after tACS. During this period, we will scan the brain using a neuroimaging device called Magnetoencephalography (MEG). Additionally, Electroencephalography (EEG) brain signals will also be collected using electrodes affixed to the scalp. We may also measure Skin conductance response (SCR) and electrocardiography (EKG) using electrodes affixed to the skin.
  3. also get a T1 MRI if they do not have an implanted SCS, DRG, intrathecal pump, or other similar device that are not MRI compatible.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

30

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

  • Name: Raghavan Gopalakrishnan
  • Phone Number: 2164459322
  • Email: gopalar@ccf.org

Study Locations

  • United States
    • Ohio
      • Cleveland, Ohio, United States, 44195
        • Recruiting
        • Cleveland Clinic
        • Contact:
          • Raghavan Gopalakrishnan
          • Phone Number: 800-223-2273
          • Email: gopalar@ccf.org

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:

  • Age 18 years or older
  • Diagnosed with Complex Regional Pain Syndrome (CRPS) Type I or II, based on Budapest criteria
  • 6 months or more of medically refractory severe pain
  • Average daily pain for past 30 days >= 5 on 0-10 scale
  • Presence of allodynia and/or hyperalgesia
  • Lower extremity CRPS: bilateral or unilateral pain
  • Not concurrently treated with neurostimulation therapies such as spinal cord stimulators (SCS)
  • Absence of co-occurring severe psychiatric disorders (PHQ-9<19 and/or GAD-7<14)

Exclusion Criteria:

  • Age under 18 years, pregnant women of any age
  • Any co-occurring pain diagnosis that might confound with allodynia/hyperalgesia resulting from CRPS reflecting a malfunction in sensory processing within the CNS.
  • Less than six months of medically refractory pain
  • Average daily pain for past 30 days <5 on 0-10 scale
  • Absence of allodynia and/or hyperalgesia
  • Concurrent neurostimulation therapies such as SCS
  • Severe disorders or conditions (e.g., cardiovascular, liver issues), terminal illness
  • PHQ-9>19 and/or GAD-7>14 (severe depression/anxiety)

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: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: alpha frequency tACS
Device: transcranial alternating current stimulation (tACS)
Real tACS will stimulate the brain in the individual alpha frequency (8-12 Hz) measured from baseline MEG
Device: transcranial alternating current stimulation (tACS)
active control tACS will stimulate the brain at 40Hz
Active Comparator: gamma frequency tACS
Device: transcranial alternating current stimulation (tACS)
Real tACS will stimulate the brain in the individual alpha frequency (8-12 Hz) measured from baseline MEG
Device: transcranial alternating current stimulation (tACS)
active control tACS will stimulate the brain at 40Hz

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
magnitude of alpha frequency band power
Time Frame: Periprocedural
measured using MEG/EEG from resting-state and during the performance of pain avoidance task. The MEG/EEG neural signals will be transformed to frequency domain to measure the magnitude of power in the alpha band.
Periprocedural

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
standard deviation in R-R length
Time Frame: Periprocedural
standard deviation in R-R length (SDNN), a measure of heart rate variability from RR interval tachogram derived from EKG.
Periprocedural
number of spontaneous skin conductance fluctuations
Time Frame: Periprocedural
number of spontaneous skin conductance fluctuations will be measured from galvanic skin conductance response time-series data.
Periprocedural

Collaborators and Investigators

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

Sponsor

The Cleveland Clinic

Collaborators

National Center for Complementary and Integrative Health (NCCIH)

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 (Estimated)

October 1, 2026

Primary Completion (Estimated)

August 31, 2028

Study Completion (Estimated)

December 1, 2028

Study Registration Dates

First Submitted

August 18, 2026

First Submitted That Met QC Criteria

August 26, 2026

First Posted (Actual)

August 28, 2026

Study Record Updates

Last Update Posted (Actual)

August 28, 2026

Last Update Submitted That Met QC Criteria

August 26, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 26-220
  • R21AT013595 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data underlying the results reported in publications, along with relevant study documentation and analytic code, may be shared with qualified researchers upon reasonable request to the study investigators. Data will be available following publication of the primary study results, subject to applicable institutional policies, informed consent provisions, and execution of an appropriate data use agreement.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

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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