Transcranial Direct Current Stimulation and Yoga for Knee Osteoarthritis

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McMaster University


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Knee Osteoarthritis


Procedure: Yoga

Study type


Funder types




Details and patient eligibility


People with knee arthritis often experience constant pain, and current treatments aren't very effective. This can lead to limited movement and more health problems. Knee arthritis is a big part of healthcare costs in Canada, and its pain is a major reason people see doctors. The pain is linked to complex nervous system changes, making current treatments, like exercise, not very successful. To address this, researchers suggest a new approach combining two things: a brain stimulation technique called Transcranial Direct Current Stimulation (tDCS) and yoga. TDCS helps with pain by changing how the brain works, and yoga, a safe practice, focuses on overall well-being. Together, the investigators aim to improve how the nervous system works from top to bottom. The research project wants to change how the arthritis pain is being managed by focusing on how it works. The investigators plan to test this combo in a study comparing real tDCS plus yoga with fake tDCS plus yoga. The investigators will look not only at pain but also at other measures related to pain and how the nervous system works. This new mix could be a meaningful way to reduce pain for people with knee arthritis.

Full description

Background: 'Omnipresent' is a common word that people living with knee osteoarthritis (KOA) use to describe the associated pain, with its unpredictability causing physical, social and emotional disruption. For many, KOA pain leads to limited mobility, reduced quality of life and increased healthcare costs KOA pain and its mechanisms are known to be complex, with alterations in nervous system signaling (ANSS) leading to persistent pain, and treatment failure to guideline-based care. Unfortunately, there is a lack of effective conservative treatments for KOA pain, including exercise which elicits only modest analgesic effects and has little impact on ANSS. To improve conservative pain management for people with KOA, it is imperative to design mechanism informed interventions and explore bold new ways to modulate ANSS to optimize patient outcomes. The investigators' novel intervention is focused on addressing the biomarker of ANSS. The investigators' solution involves using non-invasive brain stimulation (NIBS) in the form of transcranial direct current stimulation (tDCS), paired with the mind-body practice of yoga, to modify neural pathways. This is a promising and safe alternative to medications - which risk habituation, adverse events, and addiction - and that builds on the limited efficacy of performing/examining exercise in isolation. To the investigators' knowledge, this is the first trial to use this combination for chronic pain and in people with KOA. The investigators have chosen this combination as tDCS has the potential to produce synergistic nervous system effects with yoga and bolster impacts on pain. tDCS alleviates pain in older adults with KOA, particularly when combined with strengthening exercise or mindfulness. tDCS has demonstrated improved efficiency of conditioned pain modulation (CPM) resulting in pain reduction in older adults with KOA displaying deficient CPM. Meta-analyses of tDCS for the treatment of chronic pain report small to moderate effects on pain reduction, while a meta-analysis of NIBS (including tDCS) plus exercise showed moderate to large effect sizes (-0.62) compared to sham NIBS plus exercise. The investigators' approach combining 13 sessions of tDCS with yoga provides the benefits of strengthening and mindfulness in addition to nervous system regulation with the potential to produce large effects for pain reduction. Yoga modulates brain networks and is safe and accessible for many with KOA Importantly, yoga is safe for people with comorbidities through its combination of physical postures, breathing exercises, meditation and relaxation that are hypothesized to reduce pain by regulating top down and bottom-up input into the physiological systems modulating nociceptive signals. Evidence from fMRI studies indicates that yoga modifies functional connectivity in networks involved in chronic pain. Yoga is conditionally recommended by KOA guidelines due to low quality evidence and few studies. The current project seeks to shift the current paradigm for conservative pain management for people with KOA by assessing a pain mechanism informed treatment strategy in a multi-center pilot and feasibility randomized controlled trial. The investigators hypothesize that real tDCS and yoga will provide clinically meaningful reductions in pain compared to sham tDCS and yoga. This is a feasibility and pilot double-blind, randomized sham-controlled multi-center, two-arm clinical trial with a 1:1 allocation ratio. Participants will be randomized to receive active or sham tDCS and yoga for 9 weeks. Follow-up will occur at the end of the intervention and at 3 months. The Conceptual Framework for Defining Feasibility and Pilot studies, and the Standard Protocol Items- Recommendations for Intervention Trials will be used. Study results will be reported using the extended CONSORT guideline for pilot trials and the Check List Standardizing the Reporting of Interventions For Yoga (CLARIFY).


68 estimated patients




45+ years old


Accepts Healthy Volunteers

Inclusion criteria

  • community dwelling adults from Sherbrooke, Quebec, Hamilton and London, Ontario fulfilling the NICE criteria for KOA
  • ≥45 years of age
  • Diagnosis of Knee osteoarthritis OR
  • Having movement-related joint pain with either no morning knee stiffness or stiffness of 30 minutes or less AND
  • Experiencing an average pain intensity of ≥3 /10 in the past month

Exclusion criteria

  • Systemic inflammatory arthritis.
  • Any knee injection in the past 3 months.
  • Inability to independently get up and down from the floor.
  • Lower limb trauma or surgery within the last 6 months.
  • Current participation in another OA clinical trial.
  • Use of mobility aids.
  • Currently receiving care for KOA pain (e.g., physiotherapy).
  • Planned absences exceeding 1 week.
  • Contraindications to transcranial direct current stimulation (tDCS) such as neurological or neuropsychiatric conditions.
  • History of brain surgery or tumor.
  • Metallic implants.
  • Epilepsy or history of substance abuse or dependence.
  • Cochlear or ocular implant.
  • Presence of a pacemaker or cardiac defibrillator.
  • Eczema on the scalp.

Trial design

Primary purpose




Interventional model

Parallel Assignment


Double Blind

68 participants in 2 patient groups

Active tDCS
Experimental group
Active tDCS Arm: In Week 1, participants in the Active tDCS arm will undergo five in-person visits for the administration of active transcranial Direct Current Stimulation (tDCS). Subsequently, from Weeks 2 to 9, participants will receive weekly active tDCS sessions preceding the scheduled yoga sessions. For the active tDCS sessions, a constant current stimulator will be employed to deliver direct current through a pair of surface sponge electrodes (5×7 cm) soaked in saline. Participants will undergo anodal stimulation targeting the primary motor cortex (M1) contralateral to the most painful site (C3 or C4 based on the electroencephalogram 10/20 system). The cathodal electrode will be positioned on the supraorbital area contralateral to the anode. During active tDCS, a constant anodal current of 2 mA will be administered for 20 minutes, a duration known to enhance cortical excitability and alleviate pain. T
Procedure: Yoga
Sham tDCS
Sham Comparator group
Sham tDCS Arm: tDCS: In Week 1, participants in the Sham tDCS arm will attend five in-person visits for the administration of sham transcranial Direct Current Stimulation (tDCS). From Weeks 2 to 9, participants will receive weekly sham tDCS sessions before the scheduled yoga sessions. Constant current stimulator will be used to deliver direct current through a pair of surface sponge electrodes (5×7 cm) soaked in saline. Participants will undergo sham stimulation targeting the primary motor cortex (M1) contralateral to the most painful site (C3 or C4 based on the electroencephalogram 10/20 system). During sham tDCS, the electrodes will be placed in the same montage as the active tDCS; however, current will only be applied for the initial and final 30 seconds of the 20-minute session. Consequently, participants will experience the sensation of current ramping up and down but will receive no current for the remaining stimulation period.
Procedure: Yoga

Trial contacts and locations



Central trial contact

Guillaume Leonard, PhD; Lisa Carlesso, PhD

Data sourced from

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