Neural Correlates of Auriculotherapy

Chronic pain continues to be a major health issue, creating a significant societal burden, as it is an independent risk factor for opioid use disorder (OUD) and deaths. Acute pain episodes can often engender OUD due to lack of effective strategies to treat pain and prevent the transition to chronic pain. One potential non-opioid method for pain relief is auriculotherapy (AT), where acupuncture-like treatment is administered to the ear. This technique has recently been applied, with analgesia lasting for weeks, to patients with acute peri-operative pain at Shadyside hospital, but the mechanism of action of AT remains unclear.

Our overall objective is the determine the mechanism that drives AT-induced pain relief and utilize this tool as an adjuvant in our efforts to reduce the nation's reliance on opioids for pain relief. The objective of this pilot study is to illustrate that AT-related brain effects can be found with functional MRI (fMRI) for low back pain, with which the investigators have much experience. Our hypothesis is that AT reduces pain score and the abnormal brain connectivity associated with low back pain. This will identify areas of brain activity that correlate with symptom improvement after AT, allow hypothesis generation for further testing, and provide the data necessary for power calculations for an appropriately powered study in subsequent NIH HEAL grant applications.

Aim 1. Identify brain activity changes after treatment with AT. The investigators previously characterized the resting state brain activity in patients with chronic low back pain and identified key brain areas with connectivity changes related to pain state. Guided by that study, the investigators will determine if AT causes changes in resting state brain activity by comparing scans acquired before and after AT. Specifically, connectivity between the default mode network (DMN) and the insula and anterior cingulate cortex (ACC) will be examined. Changes in these areas will support the theory that AT's modulation of neural processing can be objectively measured and further characterized in a larger study.

Aim 2. Determine if detailed psychometric pain assessments demonstrate changes across AT therapy. Detailed information regarding the change in pain scores after AT are not available. Patients will complete the Patient-Reported Outcome Measurement Information System (PROMIS) Questionnaire-29 and the global impression of change questionnaires, among others, prior to and after AT treatment. This aim will also illustrate expertise in AT for chronic conditions, complimenting current efforts to demonstrate the same in acute pain after shoulder surgery. The combination of this data with the on-going acute pain study will provide the preliminary psychometric data necessary to support future NIH funding.

Aim 3. Gain insight into whether placebo mechanisms play a role in AT's efficacy. Complimentary medicine treatments such as AT are often suggested to work via placebo mechanisms. Recent work suggests that the connectivity of the right midfrontal gyrus (r-MFG) predicts the response to placebo therapy. The investigators will correlate the pain score response to AT treatment with r-MFG connectivity to determine if greater pain reduction is seen in those with greater r-MFG activity, suggesting overlap with circuits underlying placebo analgesia.

Aim 4. A small aliquot of blood will be obtained and markers of inflammation will be assessed using an ultrasensitive human 10-plex panel, which quantifies circulating levels of tumor necrosis factor (TNF-α), Interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, Interferon-y (IFNγ), and cytokine, granulocyte macrophage-colony stimulating factor (GM-CSF).