Elucidating the Central Mechanisms of Action for Green Light Therapy in Managing Chronic Pain

NCT05569486 | Not Yet Recruiting FDA Device

• 1 other identifier: 00000333
• Study Type: interventional
• Target: 70
• Locations: 1 country
• Sites: 1

Brief Summary

Investigators have previously shown that specific colors of light can alter nociception. Green light emitting diode exposure (GLED) provides long-lasting antinociception in rodents, through the visual system. No adverse effects were noted, and motor performance was not impaired. Investigator clinical trials have shown GLED is also effective in decreasing pain intensity of fibromyalgia patients and decreasing the number of headache-days per month in migraine patients. However, investigators do not yet understand the mechanisms by which GLED reduces pain. Understanding the mechanisms of action of GLED will provide additional support for using light therapy as both a treatment and as a possible diagnostic tool. While investigators do not fully understand the mechanisms of action of GLED, investigators do know that it is centrally mediated. To better elucidate the mechanism of action for GLED, investigators propose a single-blinded randomized placebo-controlled clinical trial to elucidate the central mechanism(s) of action that GLED therapy has in improving fibromyalgia pain, conducted by a team with a successful record of collaboration. Investigator's hypothesis is that GLED decreases neuroinflammation leading to modulation of the signaling in the ascending and descending pain pathways.

Conditions

Fibromyalgia

Outcome Measures

Primary Outcomes (1)

• Decreased activation of glial cells.

  By exposure to GLED investigators hypothesize that glial cells will be decreased, investigators will measure this by using positron emission tomography (PET) scan, scans will be conducted at baseline and the end of study

  [Time Frame: 10 - 22 weeks, depending on study arm]

Secondary Outcomes (4)

• Decreasing Central Nervous System inflammation (CNS), Increasing Endorphins.

  [Time Frame: 10 - 22 weeks, depending on study arm]

• Decreasing the activity of ascending pain pathway, and increasing the activity the descending pain pathway

  [Time Frame: 10 - 22 weeks, depending on study arm]

• Improvement in Fibromyalgia Impact Questionnaire score

  [Time Frame: 10 - 22 weeks, depending on study arm]

• Decreased objective and subjective pain scores to mechanical and thermal stimulation

  [Time Frame: 10 - 22 weeks, depending on study arm]

Study Arms (2)

Green light-emitting diode (GLED)

EXPERIMENTAL

Subjects randomized to this arm will be exposed to GLED 2 hours a day for 10 weeks

Device: Green Light

White light-emitting diode (WLED)

PLACEBO COMPARATOR

Subjects randomized to this arm will be exposed to WLED 2 hours a day for 10 weeks

Device: Green Light

Interventions

Green Light DEVICE

This is a low-energy device. It produces almost no heat because it uses an LED source for light. The device does not store energy or electrical power that can be discharged later.

Green light-emitting diode (GLED); White light-emitting diode (WLED)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• years or older who can speak and understand English
• Meets the diagnostic criteria for fibromyalgia accroding to the 2016 revisions to the 2010/2011 fibromyalgia diagnostic criteria.
• Average numeric pain score of 5 out of 10 or greater over the 10 weeks prior to enrolling in the study, and failure of medical therapy to control their pain.

You may not qualify if:

• Serious mental illness defined as distortions of perception, delusions, hallucinations, and unusual behaviors resulting in loss of contact with reality. This will be assessed during the screening interview. Patients with psychiatric disorders will have their medical record reviewed prior to enrollment
• History of color blindness or uncorrected cataracts
• Subjects receiving remuneration for their medical condition.
• Genotype of low affinity binders for translocator protein, (TSPO), as patients with low affinity binding TSPO may not have adequate uptake for the radioactive tracer used for the PET scan.

Sponsors & Collaborators

• University of Arizona: lead
• Banner Alzheimer's Institute: collaborator

Study Sites (1)

Banner University Medical Center Multispecialty Services Clinic

Tucson, Arizona, 85711, United States

Location

Related Publications (6)

• Burckhardt CS, Clark SR, Bennett RM. The fibromyalgia impact questionnaire: development and validation. J Rheumatol. 1991 May;18(5):728-33.

  PMID: 1865419 BACKGROUND

• Potvin S, Marchand S. Pain facilitation and pain inhibition during conditioned pain modulation in fibromyalgia and in healthy controls. Pain. 2016 Aug;157(8):1704-1710. doi: 10.1097/j.pain.0000000000000573.

  PMID: 27045524 BACKGROUND

• Overstreet DS, Michl AN, Penn TM, Rumble DD, Aroke EN, Sims AM, King AL, Hasan FN, Quinn TL, Long DL, Sorge RE, Goodin BR. Temporal summation of mechanical pain prospectively predicts movement-evoked pain severity in adults with chronic low back pain. BMC Musculoskelet Disord. 2021 May 10;22(1):429. doi: 10.1186/s12891-021-04306-5.

  PMID: 33971876 BACKGROUND

• Mackey IG, Dixon EA, Johnson K, Kong JT. Dynamic Quantitative Sensory Testing to Characterize Central Pain Processing. J Vis Exp. 2017 Feb 16;(120):54452. doi: 10.3791/54452.

  PMID: 28287532 BACKGROUND

• Yarnitsky D, Bouhassira D, Drewes AM, Fillingim RB, Granot M, Hansson P, Landau R, Marchand S, Matre D, Nilsen KB, Stubhaug A, Treede RD, Wilder-Smith OH. Recommendations on practice of conditioned pain modulation (CPM) testing. Eur J Pain. 2015 Jul;19(6):805-6. doi: 10.1002/ejp.605. Epub 2014 Oct 20.

  PMID: 25330039 BACKGROUND

• Yarnitsky D, Granot M, Nahman-Averbuch H, Khamaisi M, Granovsky Y. Conditioned pain modulation predicts duloxetine efficacy in painful diabetic neuropathy. Pain. 2012 Jun;153(6):1193-1198. doi: 10.1016/j.pain.2012.02.021. Epub 2012 Apr 3.

  PMID: 22480803 BACKGROUND

MeSH Terms

Conditions

Fibromyalgia

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Neuromuscular Diseases; Nervous System Diseases

Study Officials

• Mohab M Ibrahim, PhD., MD

  University of Arizona

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Mohab M Ibrahim, PhD., MD

CONTACT

520-871-7246; mibrahim@anesth.arizona.edu

Virginia Ellis

CONTACT

520-626-3099; virginiaellis@anesth.arizona.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor, Anesthesiology

Study Record Dates

• First Submitted: October 3, 2022
• First Posted: October 6, 2022
• Study Start: January 1, 2026
• Primary Completion (Estimated): December 30, 2029
• Study Completion (Estimated): December 30, 2029
• Last Updated: October 14, 2025

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)