Transcranial direct-current stimulation (tDCS), a non-pharmacological, non-invasive, painless brain stimulation treatment is now emerging as a useful technique for managing chronic pain. A new first double-blind, clinical randomized trial analysis exhibited significant progress in pain management among older patients with knee osteoarthritis (OA).

According to Dr. Brian Ahn, Ph.D., RN, University of Texas Health Center at Houston, the estimation of the effects of tDCS in Knee OA patients was particular interest to them as knee OA is one of the prominent causes of pain & disability among aged people.

The tDCS has been estimated for various problems, from depression to stroke rehabilitation, dementia, and cognitive aging. This study was the first double-blind, randomized study of tDCS in chronic pain. The study was presented at American Pain Society (APS) 2017 Annual Scientific Meeting. The study comprised 40 adults with a mean age of 59 years. These participants randomly received five daily sessions of either sham treatment or tDCS. The total span of each session was about 20 minutes. As tDCS produces a tingling sensation, the sham treatment implicated 30 seconds of tDCS current at the commencement of the session and 30 seconds in the end to provide a similar response.

A code was used to deliver the current. The code allowed the tDCS operator to be blinded to the treatment received by the patient. The tDCS comprised anode and cathode electrodes. Anode electrode was implanted over the primary motor cortex of the brain hemisphere. This region of the brain was contralateral to the affected knee. On the other hand, cathode electrode was implanted over supraorbital regions, which was ipsilateral to the affected knee.

The results, after five sessions of tDCS, showed greater reduction than sham group in knee pain. This reduction was measured on the pain severity scale of 0 to 100 in the tDCS group (18.50 ± 3.60) compared with the sham group (6.45 ± 2.26). As the study was small, it is essential to observe an effect size. The effect size of this study was large which indicates that the treatment was effective.

As per Dr Ahn, the mechanism by which tDCS may direct knee osteoarthritis pain could be linked to its neuromodulatory effects. He further added that the current data demonstrates knee OA as a centralized pain, so there could be centrally modulated mechanisms.

The co-author of the study, Dr. Adam J. Woods, MD, assistant director of the Center for Cognitive Aging and Memory at the University of Florida's McKnight Brain Institute, Gainesville found results of the study quite promising. He further added that the overall effect size was large and exciting.