Transcranial direct-current stimulation (tDCS) has shown promise to decrease fatigue. However, it has never been examined in primary Sjogren Syndrome (pSS).
To assess the effect of a tDCS protocol on fatigue in patients with pSS.
This is a parallel, double-blind pilot study (NCT04119128). Women aged 18-65 years, with pSS, on stable pharmacological therapy, with complaints of fatigue for at least three months, and with scores >5 on Fatigue Severity Scale (FSS) were included. We randomized 36 participants to receive five consecutive or sham tDCS sessions, with an intensity of 2 mA, for 20 min/day.
After five tDCS sessions, fatigue severity assessed by the FSS (primary outcome) demonstrated a mean group difference of -0.85 [95% confidence interval (CI) -1.57, -0.13; effect size 0.80] favouring the active group. The active group presented significantly greater reductions in fatigue as measured by the EULAR Sjögren's Syndrome Patient Reported Index after five tDCS sessions [mean group difference: 1.40; 95%CI -2.33, -0.48; effect size 1.04]. Although there were no between-group differences in the secondary outcomes of sleep, mood and anxiety, within-group comparisons evidenced a small but significant difference in the active group for pain and sleep. There were no significant cortisol changes. All reported adverse events were mild and transitory.
tDCS seems to be safe and reduce fatigue in pSS. A differential effect on pain and sleep may underlie its effects. Further studies are needed to optimise tDCS treatment strategies in pSS.