Feasibility of Near-infrared Spectroscopy to Measure Cortical Pain Pathway (Brain) Activation During Dry Needling

The benefit experienced by some patients when treated with dry needling,1 combined with the field-expedient nature of this intervention, make dry needling uniquely suited for the military healthcare environment. An improved understanding of the mechanism by which dry needling exerts its clinical benefits will allow clinicians to adopt more efficacious treatment strategies for Soldiers with chronic musculoskeletal pain. The proposed study will utilize functional near-infrared spectroscopy and structural health monitoring (SHM) to provide insight on the central and peripheral mechanisms of dry needling. Phase 1 will compare the cortical pain pathway response of thirty participants with non-traumatic shoulder pain receiving either true or sham dry needling. An additional 15 participants will be enrolled to receive true dry needling to determine if brain responses may be able to predict clinical improvement (responders versus non-responders) in phase 2. Since chronic pain after musculoskeletal injury is the leading cause of medical discharge from service and a primary source of disability in the U.S. military2,3, improved complementary and alternative treatment strategies have the potential to have a large impact on both military readiness and health care costs within the Armed Forces.

This study supports a line of ongoing investigation aimed at improving the diagnosis, management, and treatment of chronic pain after musculoskeletal injury. Continued progress in this arena requires novel methods to measure central nervous system (brain) mechanism of action and its role in identification of the unique transition of musculoskeletal injury to chronic pain. The purpose of this study is to use near-infrared spectroscopy (NIRS) to measure changes along cortical pain pathways in the brain related to true and sham dry needling treatment.

Specific Aim #1: The investigators will compare the cortical pain pathway response during dry needling treatment to sham dry needling treatment using NIRS in two groups of patients with chronic shoulder pain.

The investigators hypothesize that decreased cortical activity will be seen in the dorsolateral prefrontal cortex (DLPFC) in those treated with true dry needling compared to those treated with sham dry needling.

Specific Aim #2: The investigators will evaluate whether the cortical pain pathway response (imaged using NIRS) during dry needling predicts 1-week improvement in shoulder muscle response, local hypoalgesia, and self-reported pain and disability in the group of patients that received true dry needling treatment. The investigators hypothesize that decreased cortical activity in the DLPFC will be associated with improvements in shoulder muscle response, local hypoalgesia, and self-reported pain and disability in those treated with true dry needling.

Eligibility Criteria:
Inclusion Criteria:

(all of the following) Active duty DoD beneficiary Age 18-50 years old Non-traumatic shoulder pain rated at least 4/10 on the Numeric Pain Rating Scale Right-handed

Exclusion Criteria:

* Anticoagulant medication use Bleeding disorders Shoulder pain referred from cervical spine Full-thickness rotator cuff tears Known pregnancy Inability to lie prone Left- or mixed-handed