Efficacy of Home-Based Transcranial Direct Current Stimulation on Experimental Pain Sensitivity in Older Adults with Knee Osteoarthritis: A Randomized, Sham-Controlled Clinical Trial

Abstract

Although transcranial direct current stimulation (tDCS) is encouraging regarding clinical pain intensity for individuals with knee osteoarthritis, very few studies have explored its impact on experimental pain sensitivity, which may hinder our understanding of underlying therapeutic mechanisms. The purpose of this study was to assess the efficacy of 15 home-based tDCS sessions on experimental pain sensitivity and explore its relationships with clinical pain intensity. We randomly assigned 120 participants to active tDCS (n = 60) and sham tDCS (n = 60). Quantitative sensory testing (QST) was used, including heat pain threshold and tolerance, pressure pain threshold, and conditioned pain modulation. Patients in the active tDCS group exhibited reduced experimental pain sensitivity as reflected by all QST measures at the end of treatment. Furthermore, correlations were observed between changes in clinical pain intensity and experimental pain sensitivity. These findings warrant further studies on tDCS and experimental pain sensitivity in patients with knee osteoarthritis and exploring the magnitude and sustainability of effects on a longer term.

Feasibility, Acceptability, and Efficacy of Home-Based Transcranial Direct Current Stimulation on Pain in Older Adults with Alzheimer’s Disease and Related Dementias: A Randomized Sham-Controlled Pilot Clinical Trial

“…Our findings also suggest that the chronic pain experienced by individuals with ADRD involves central processing mechanisms since tDCS was able to impact pain intensity. Indeed, tDCS is a neuromodulation method potentially affecting pain processing pathways as shown in our studies using neuroimaging and conditioned pain modulation (CPM) measures [ 48 , 80 , 81 , 82 ]. We found significant changes in hemodynamic brain activity measured with functional near-infrared spectroscopy (fNIRS) [ 80 , 81 , 82 ], and simultaneously observed a significant increase in CPM in the active group as opposed to the sham group after tDCS [ 48 ], which coincides with tDCS studies using functional magnetic resonance imaging (fMRI) in both healthy subjects [ 83 , 84 ] and chronic pain patients [ 85 , 86 ].…”

“…Indeed, tDCS is a neuromodulation method potentially affecting pain processing pathways as shown in our studies using neuroimaging and conditioned pain modulation (CPM) measures [ 48 , 80 , 81 , 82 ]. We found significant changes in hemodynamic brain activity measured with functional near-infrared spectroscopy (fNIRS) [ 80 , 81 , 82 ], and simultaneously observed a significant increase in CPM in the active group as opposed to the sham group after tDCS [ 48 ], which coincides with tDCS studies using functional magnetic resonance imaging (fMRI) in both healthy subjects [ 83 , 84 ] and chronic pain patients [ 85 , 86 ]. In relation to ADRD, recent evidence suggests that there might be a link between pathological processes of ADRD and chronic pain [ 87 ].…”

“…In addition, tDCS has been shown to improve memory and general cognitive function in people with ADRD [ 46 ]. Moreover, conventionally offered in a clinic setting, we have tested the feasibility, acceptability, and efficacy of tDCS in the home setting with older adults and obtained statistically and clinically significant results on pain [ 47 , 48 ]. This approach, enhanced by recent technological advances [ 49 ], offers convenience and accessibility to evidence-based nonpharmacological treatment of pain for older adults, including persons with ADRD who have difficulties attending clinic-based sessions [ 46 , 50 , 51 , 52 , 53 ].…”

Self-administered transcranial direct current stimulation treatment of knee osteoarthritis alters pain-related fNIRS connectivity networks

“…9 Our research has previously shown that tDCS has a beneficial effect on clinical subjective measures of pain in knee OA patients, 10 as well as experimental pain sensitivity. 11,12 We reported the efficacy of home-based tDCS treatment on experimental pain sensitivity measures such as the heat pain threshold (HPTh), heat pain tolerance (HPTo), pressure pain threshold (PPT), and conditioned pain modulation (CPM), as well as its relationship with clinical pain intensity measures such as the numeric rating scale (NRS) and Western Ontario and McMaster Universities Osteoarthritis Index. Changes in NPTh, NPTo, PPT, CPM, and NRS between the active and sham groups were found to be statistically significant after the third week of treatment 12 and 3 months from the baseline.…”

“…To our knowledge, this is the first study assessing changes in neural connections assessed using fNIRS between cohorts that underwent home-based, self-administered tDCS treatment versus sham tDCS for several weeks, and it pairs with other reports from our group focused on clinical outcomes. 10,[12][13][14][15][41][42][43] 2 Materials and Methods…”