Journal of Pain Research (Sep 2018)
Bayesian analysis of the effect of transcranial direct current stimulation on experimental pain sensitivity in older adults with knee osteoarthritis: randomized sham-controlled pilot clinical study
Abstract
Hyochol Ahn,1 Robert Suchting,2 Adam J Woods,3 Hongyu Miao,4 Charles Green,5 Raymond Y Cho,6 Eunyoung Choi,7 Roger B Fillingim8 1Department of Nursing Research, University of Texas Health Science Center at Houston, Cizik School of Nursing, Houston, TX, USA; 2Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX; USA; 3Department of Clinical and Health Psychology, University of Florida Center for Cognitive Aging and Memory, McKnight Brain Institute, Gainesville, FL, USA; 4Department of Biostatistics and Data Science, University of Texas Health Science Center at Houston, School of Public Health, Houston, TX, USA; 5Department of Pediatrics, University of Texas Health Science Center at Houston, Center for Clinical Research and Evidence-Based Medicine, Houston, TX, USA; 6Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX, USA; 7Department of Patient Care, Epic Health Services, Houston, TX, USA; 8Department of Community Dentistry and Behavioral Science, University of Florida Pain Research and Intervention Center of Excellence, Gainesville, FL, USA Purpose: Previous studies have indicated that transcranial direct current stimulation (tDCS) with the anode over the motor cortex and the cathode over the contralateral supraorbital region is effective in reducing clinical pain in patients with chronic pain, but these studies have not focused on experimental pain sensitivity. Therefore, the aim of this study was to examine the effect of tDCS on experimental pain sensitivity in older adults with knee osteoarthritis (OA). Patients and methods: Forty community-dwelling participants aged 50–70 years with knee OA pain were randomly assigned to receive five daily sessions of 2 mA tDCS for 20 minutes (n = 20) or sham tDCS (n = 20) using a parallel group design. A multimodal quantitative sensory testing battery was completed, including heat pain, pressure pain threshold (PPT), punctate mechanical pain, and conditioned pain modulation (CPM). Results: The active tDCS group showed greater increases in heat pain thresholds and tolerances, PPTs, and CPM, and reductions in punctate pain. In addition, beneficial changes in experimental pain measures were associated with reductions in clinical pain. Future studies are needed to extend these findings to better understand the underlying mechanisms of tDCS as well as to optimize treatment parameters including number and duration of stimulation sessions. Conclusion: Our findings demonstrate that tDCS reduces experimental pain sensitivity, and these beneficial changes in experimental pain measures were associated with reductions in clinical pain. Keywords: transcranial direct current stimulation, knee osteoarthritis, quantitative sensory testing, Bayesian analysis
