Efficacy of transcranial direct current stimulation over primary motor cortex (anode) and contralateral supraorbital area (cathode) on clinical pain severity and mobility performance in persons with knee osteoarthritis: An experimenter- and participant-blinded, randomized, sham-controlled pilot clinical study

Abstract

Background Previous studies indicate that transcranial direct current stimulation (tDCS) with anode over motor cortex (M1) and cathode over contralateral supraorbital region (SO) may be effective in reducing pain, but these studies are limited in number and have not focused on older adults with osteoarthritis (OA). Objective To evaluate the preliminary efficacy and safety of M1-SO applied tDCS on clinical pain severity and mobility performance in adults with knee OA pain. Methods Forty 50- to 70-year-old community-dwelling participants with knee OA were randomly assigned to receive five daily sessions of 2 mA tDCS for 20 min (n = 20) or sham tDCS (n = 20). We measured clinical pain severity via Numeric Rating Scale, Western Ontario and McMaster Universities Osteoarthritis Index, and Short-Form McGill Pain Questionnaire. In addition, we measured mobility performance using the 6-Minute Walk Test and the Short Physical Performance Battery. Moreover, we obtained a sensation/safety questionnaire and measured cognition changes using the PROMIS-Applied Cognition-Abilities-Short Form 8a. Results Active tDCS over M1-SO significantly reduced Numeric Rating Scale of pain compared to sham tDCS after completion of the five daily sessions, and remained up to three weeks. No other measures were significantly different from sham. Participants tolerated tDCS over M1-SO well without serious adverse effects or cognition changes. Conclusion Although not consistent in all pain measurements, our findings demonstrate promising clinical efficacy for reduction in pain perception for older adults with knee OA. Trial registration ClinicalTrials.gov Identifier NCT02512393.

Frequency‐dependent top‐down modulation of temporal summation by anodal transcranial direct‐current stimulation of the primary motor cortex in healthy adults

“…This suggests activation of the opioid system, in part, mediates the analgesic effects of primary motor cortex tDCS and others have shown the release of opioids in the midbrain in both healthy subjects (Dossantos et al, 2014) and during chronic pain (Dossantos et al, 2012). Similar clinical pain-relieving effects have been seen in elderly patients with chronic musculoskeletal pain (Ahn et al, 2017;Harvey et al, 2017), small-fibre neuropathy (Kim et al, 2013) and in patients with chronic visceral pain (Volz et al, 2016). Further positive results have demonstrated that primary motor cortex stimulation may provide an effective treatment in drug-resistant neuropathic pain conditions; showing analgesic effects in phantom limb pain (Bolognini et al, 2015) and trigeminal neuralgia (Hagenacker et al, 2014).…”

“…They may also provide insight into the efficacy of tDCS in both clinical and nonclinical settings. There is a growing body of evidence that suggests tDCS is more effective in patients with chronic pain Borckardt et al, 2011Borckardt et al, , 2017Jurgens et al, 2012;Kim et al, 2013;Hagenacker et al, 2014;Bolognini et al, 2015;Volz et al, 2016;Ahn et al, 2017;Harvey et al, 2017;Khedr et al, 2017a) compared to studies that have attempted to dissect the analgesic mechanisms in healthy subjects (Boggio et al, 2008;Csifcsak et al, 2009;Hansen et al, 2011;Jurgens et al, 2012;Aslaksen et al, 2014;Ihle et al, 2014). These lines of evidence have now not only shown a reduction in pain intensity in chronic pain patients, but also distinct changes in the brain regions involved in the top-down modulation of pain processing.…”

“…Transcranial direct-current stimulation (tDCS) can modulate cortical activity by depolarizing or hyperpolarizing cortical neuronal resting membrane potentials depending on the polarity of current stimulation (Purpura and McMurtry, 1965;Gorman, 1966). There is a growing body of evidence that anodal tDCS applied over the primary motor cortex provides pain relief in a number of neuropathic, visceral and inflammatory chronic pain conditions (Borckardt et al, 2011(Borckardt et al, , 2017Jurgens et al, 2012;Kim et al, 2013;Hagenacker et al, 2014;Bolognini et al, 2015;Volz et al, 2016;Ahn et al, 2017;Harvey et al, 2017;Khedr et al, 2017a). However, the analgesic mechanisms mediating these effects have been more difficult to elucidate.…”

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

“…Persons with OA are reported to display higher experimental pain sensitivity, such as lower heat pain thresholds and tolerances, lower pressure pain threshold (PPT), and higher punctate mechanical pain. 6 , 18 , 19 However, previous studies, including ours, examined clinical outcomes associated with tDCS, 11 , 13 , 20 , 21 but few studies reported changes in experimental pain sensitivity after tDCS. The examination of the effect of tDCS on experimental pain sensitivity, which can be different based on the parameters of tDCS (eg, polarity, electric current intensity, and target site), could help clinicians and researchers to better understand the underlying mechanisms of action involved with tDCS and the role played by the cortex in the integration of nociceptive information.…”

Osteoarthritis year in review 2018: rehabilitation and outcomes

“…Thus, while evidence supports combined interventions for thumb OA, we are unable to make specific recommendations regarding combined interventions for knee OA, or for other affected joints. With respect to adjunct interventions, we found evidence to support the use of tape for knee OA 21,55,57 , assistive devices for hand OA 59 , thumb splints for thumb OA 60 , manual therapy for knee OA 23,45,47,53 and neck OA 65 , acupuncture for knee OA 44 , and electrophysical agents for knee OA 19,22,48 (Tables III and IV), while conflicting evidence was found for transcranial direct current stimulation (tDCS) 30,37 (Table IV). Taken together with established clinical guidelines, our findings reinforce that these interventions should be adjuncts to accompany core recommended interventions for OA, rather than be used as standalone or key treatments 2,3,9e16 .…”