Pain relief for osteoarthritis through combined treatment (PROACT): Protocol for a randomized controlled trial of mindfulness meditation combined with transcranial direct current stimulation in non-Hispanic black and white adults with knee osteoarthritis

Abstract

Knee osteoarthritis (OA) is a leading cause of late life pain and disability, and non-Hispanic black (NHB) adults experience greater OA-related pain and disability than non-Hispanic whites (NHWs). Recent evidence implicates psychosocial stress, cognitive-attentional processes, and altered central pain processing as contributors to greater OA-related pain and disability among NHBs. To address these ethnic/race disparities, this clinical trial will test whether a mindfulness intervention (Breathing and Attention Training, BAT) combined with transcranial direct current stimulation (tDCS) will enhance pain modulatory balance and pain-related brain function, reduce clinical pain, and attenuate ethnic differences therein, among NHBs and NHWs with knee OA. Participants will complete assessments of clinical pain, function, psychosocial measures, and quantitative sensory testing (QST), including mechanical temporal summation and conditioned pain modulation. Neuroimaging will be performed to examine pain-related brain structure and function. Then, participants will be randomized to one of four groups created by crossing two BAT conditions (Real vs. Sham) with two tDCS conditions (Real vs. Sham). Participants will then undergo five treatment sessions during which the assigned BAT and tDCS interventions will be delivered concurrently for 20 min over one week. After the fifth intervention session, participants will undergo assessments of clinical pain and function, QST and neuroimaging identical to the pretreatment measures, and monthly follow-up assessments of pain will be conducted for three months. This will be the first study to determine whether mindfulness and tDCS treatments will show additive or synergistic effects when combined, and whether treatment effects differ across ethnic/race groups.

Keywords: Brain imaging; Mindfulness; Osteoarthritis; Pain; Pain modulation; Transcranial direct current stimulation.

Figure 1.. Heuristic Model of Ethnic Differences in OA-Related Pain and Disability and Proposed Treatment Effects.

Our model posits that ethnic group differences in psychosocial stress and cognitive-attentional processes negatively impact central pain processing, reflected by altered resting state and pain-evoked brain function and pain modulatory imbalance, leading to greater OA-related pain and disability among African American adults. We propose that transcranial direct current stimulation (tDCS) will have direct effects on central pain processing and indirect effects on psychosocial processes. Our mindfulness intervention, Breathing and Attention Training (BAT) will directly impact both psychosocial processes (including stress and pain-related cognitive-attentional processes) and central pain processing. Importantly, we believe that neuroplastic benefits of tDCS will potentiate the ability of BAT to produce adaptive changes in pain-related brain function. Note: dashed line = indirect effect.

Figure 2.. Protocol Timeline.

The figure presents the protocol flow for each participants, including screening, baseline assessments (Visits 1 & 2), intervention visits (Visits 3–7), post-treatment assessment (Visit 7), and three monthly follow-up assessments.