Immersive Virtual Reality and Central Sensitization in People With Chronic Pain

Patients with chronic low back pain from Dr. Robert Edwards' study at the Brigham \& Women's Pain Institute that examines sensory and pain perceptions in patients with chronic pain who use opioids will complete quantitative sensory testing (QST) and current pain levels will be obtained. Subsequently, 20-minutes of Immersive Virtual Reality (IVR) will be completed and then QST testing will be completed again post-IVR.

We will partner with Dr. Robert Edwards at the Brigham \& Women's Pain Institute. Dr. Edward's is an expert in testing central sensitization using quantitative sensory testing (QST).12 QST involves cutaneous (skin) psychophysical (semi-subjective) testing to assess sensory and pain perception pathways.13 QST identifies the intensity of stimuli (touch) is needed to feel something (threshold of detection) and how perception of stimuli changes if it is repeated many times (temporal summation).14 In people with central sensitization, even light intensity of stimulation is perceived as pain and similar intensity stimuli becomes more painful with multiple applications. We hypothesize that people with chronic pain will demonstrate clinically important reductions in the threshold of detection and temporal summation after IVR, which will demonstrate that IVR can affect central sensitization.

We will complete two types of QST testing: Mechanical Pressure Pain Thresholds (MPPTh) to test for threshold of detection, and Mechanical Temporal Summation of Pain (MTSP) to test for temporal summation. In MPPTh we will measure the amount of pressure needed at the shoulder and thumb (body sites that routinely do not have pain in people with low back pain) to elicit a pain report from participants. In MTSP we will apply a train of 10 stimuli (light pinprick) at the rate of 1 per second on the middle finger and have participants rate the painfulness of the first, fifth, and tenth stimulus.

During the study, we will recruit 20 patients with chronic low back pain from Dr. Edwards' study examining sensory and pain perceptions in patients with chronic pain who use opioids. We will complete QST testing and obtain current pain levels. We will complete 20-minutes of IVR, and then complete QST testing again. We will compare pre-IVR MPPTh and MTSP with post IVR levels. We anticipate short term, clinically important decreases in QST levels providing initial confirmation that IVR can positively change central sensitization.

Eligibility Criteria:
Inclusion Criteria:

1. Age 25-65
2. CLBP lasting for more than 6 months as the primary complaint
3. Typical pain ratings ≥ 4/10 on a visual analogue scale
4. Currently prescribed oral opioid therapy and under consideration for dose reduction by the prescribing clinician.
5. able to speak and understand English

Exclusion Criteria:

1. Evidence of delirium, dementia, psychosis, or other cognitive impairment preventing completion of study procedures
2. current (i.e., active) substance use disorder (SUD).
3. history of myocardial infarction or other serious cardiovascular condition.
4. current peripheral neuropathy.
5. current pregnancy, or intention to become pregnant during the study.
6. current intrathecal pump
7. history of seizures
8. history severe motion sickness