Arthritis is a leading cause of pain, impaired daily activity, and disability in people 45 years and older. Osteoarthritis (OA) is the most common arthritic condition, and the knee is the most commonly affected joint. Because pharmacologic treatments can increase the risk of adverse events among older adults, there is a growing interest in non-pharmacologic interventions targeting central nervous system pain processing for this population. Specifically, noninvasive brain stimulation, such as transcranial direct current stimulation (tDCS), has received significant attention for the treatment of pain in chronic conditions owing to its neuromodulatory effects. Thus, we sought to assess the preliminary efficacy of tDCS on clinical pain severity in adults with knee OA pain. We conducted a double-blind, randomized, sham-controlled pilot clinical study in 40 community-dwelling participants with knee OA who were 50−70 years old. The participants were randomly assigned to receive either five daily sessions of 2mA tDCS for 20 minutes or sham tDCS. The anode electrode was placed over the primary motor cortex of the hemisphere contralateral to the affected knee, and the cathode electrode was placed over the supraorbital region ipsilateral to the affected knee. Clinical pain severity was measured at baseline and after tDCS via a numeric scale (0 to 100) rating current knee pain. The mean age was 59 years (SD = 8 years), and 53% were female. After five daily sessions, the tDCS group had a greater reduction in knee pain (18.50 ± 3.60) than the sham group (6.45 ± 2.26). The mean difference between groups was 12.05 (t=2.83, df=38, p=.007, Cohen’s d = 0.90). Our preliminary results show that tDCS reduced clinical pain severity in adults with knee OA. Further studies with larger samples and longer-term follow-ups are needed.
© 2017 Published by Elsevier Inc.