Rheumatoid arthritis (RA) patients saw significant reductions in pain with transcranial direct current stimulation (tDCS) delivered at home, a sham-controlled trial reported here indicated.
After 4 weeks of treatment, patients receiving active stimulation showed reductions from baseline in self-reported pain averaging 33.5 points on a 100-point scale, compared with a 14.1-point decline among patients using the same device but inactivated, according to Stephanie Pilotti, MSc, of Universidade Federal do Rio Grande do Sul in Porto Alegre, Brazil.
The difference of 19.4 points was significant (P=0.003), Pilotti told attendees at the European Alliance of Associations for Rheumatology annual meeting.
RA may be an inflammatory joint disease, but pain is still transmitted through the nervous system and thus may be amenable to neurological interventions. Pilotti observed that numerous studies in animal models and humans have established that when pain signalling becomes chronic, plasticity in the central nervous system (CNS) can, over time, alter how these signals are processed. Pain may be amplified and sensitivity to pain can increase to the point of allodynia (interpreting normal touch sensations as painful). One study she cited found that RA patients develop this sort of central sensitization "even in the absence of active inflammation."
One non-drug approach to alleviating chronic pain has been tDCS. Some studies have found that it can relieve pain from fibromyalgia and a variety of other chronic pain states. The theory is that it normalizes pain signalling, Pilotti explained, without dulling sensation from genuinely injurious stimuli.
For the new study, her group enrolled 34 women with stable RA not marked by extreme inflammation, randomizing them in equal numbers to active or sham therapy. Eligibility criteria included rating their pain at 40 or higher out of 100. Patients for whom tDCS would be contraindicated (those with epilepsy or cranial metallic implants, for example) were excluded, as were those with concomitant rheumatologic conditions.
Patient age averaged about 56, with a median RA duration of 10 years. Mean 28-joint Disease Activity Score values were just over 2.8. They rated their pain as fairly severe: averaging 72 points in the group randomized to active tDCS and 63 in the sham-treated control group.
The tDCS device resembled a cloth helmet. Patients were instructed to put it on for 20-minute sessions once a day for 5 days each week for 4 weeks; they were supervised remotely, however. Active treatment consisted of 2 mA of current. In the control group, some current was delivered briefly at the beginning and end of each session in an effort to maintain blinding.
In addition to rating their pain, patients also completed other self-evaluations, including their use of analgesic drugs (days/week). Blood samples were taken as well to measure RA and inflammation markers, plus brain-derived neurotrophic factor (BDNF) to get an objective look at CNS responses to treatment.
At the 4-week evaluation, weekly analgesic use had fallen by 2.3 days with active treatment versus a 1.4-day decrease among controls (P=0.025). No significant change was seen in maximum pain pressure threshold, but the minimum threshold rose by 1.0 kg/cm2 in the active treatment group versus an increase of 0.4 kg/cm2 in the sham group (P=0.003).
Changes in other measures, such as physical function, fatigue, and sleep quality, did not differ significantly between active and sham treatment. Nor were there any between-group differences in RA-related markers including tumor necrosis factor, interleukin-1, or interleukin-6. However, mean BDNF levels rose with active treatment while it declined in the sham group (P=0.002).
Pilotti and colleagues also checked in with participants 3 months after completing the 4-week program to have them rate their pain. It rebounded from the immediate post-treatment levels in both groups and the between-group difference was no longer significant; the absolute means remained below baseline, however.
Active treatment did not appear to induce more adverse events such as headache, scalp pain, itching, insomnia, and trouble concentrating relative to sham therapy. No severe problems occurred in either group, and all patients completed the 4-week treatment.
"This approach may represent a valuable adjuvant to the management of chronic pain in RA patients," Pilotti concluded.
Disclosures
No external funding for the study was reported.
Pilotti and other authors declared they had no relevant financial interests.
Primary Source
European Alliance of Associations for Rheumatology
Source Reference: Pilotti S, et al "Effect of home-based transcranial direct current stimulation on pain in rheumatoid arthritis patients with low inflammatory activity: a randomized, double-blind, sham-controlled clinical trial" EULAR 2025; Abstract OP0280.
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