The Efficacy of Remotely Supervised Transcranial Direct Current Stimulation on Conditioned Pain Modulation in Older Adults with Knee Osteoarthritis Pain

Abstract

Osteoarthritis is a leading cause of pain, impaired daily function, and disability in older adults. Pharmacological and surgical interventions can increase the risk of side effects among older adults, and therefore, nonpharmacological interventions are promoted by the National Pain Strategy. Specifically, transcranial direct current stimulation (tDCS) targeting central nervous system pain processing has received growing attention for the treatment of chronic pain. Remotely supervised tDCS extended the analgesic properties of tDCS from the clinical setting to benefit participants in the comfort of their homes. Thus, we sought to assess the preliminary efficacy of tDCS on conditioned pain modulation in adults with knee OA pain. We conducted a single-group, open-label study in 20 community-dwelling older adults (ages 50–85 years) with knee osteoarthritis. tDCS with anode over the primary motor cortex and cathode with contralateral supraorbital region was applied with a constant current intensity of 2mA for 20 minutes every weekday for two weeks (Monday to Friday) for a total of 10 sessions. All tDCS sessions were remotely supervised by the trained research staff using secure videoconferencing software. Conditioned pain modulation (CPM) was measured by determining the change in pressure pain threshold on the trapezius immediately following immersion of the contralateral hand up to the wrist in a cold-water bath for up to one minute. The mean age of participants was 61 years (SD = 7 years), and 75% were female. CPM was significantly increased from 0.9 (SD=0.7) to 1.3 (SD=0.6) at the end of treatment (effect size = 0.4). Our preliminary results show that tDCS increased CPM in adults with knee OA. Randomized controlled trials with larger samples and longer-term follow-ups are needed to corroborate these promising findings regarding the effects of remotely supervised tDCS. This study was supported in part by the Theodore J. and Mary E. Trumble Endowment from The University of Texas Health Science Center at Houston and National Institute of Nursing Research (R15NR018050, R01NR019051).