Sex-specific effects of digital home-based neuromodulation combined with mindfulness-based meditation on knee...

We evaluated the effects of digital home-based transcranial direct current stimulation (tDCS) paired with audio-delivered mindfulness-based meditation (MBM) on knee-specific clinical pain and symptoms in patients with symptomatic knee osteoarthritis, assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). As sex is a major source of variability in responses to tDCS and MBM, we examined treatment effects by sex.

Participants (N = 200) from a double-blind, randomized, sham-controlled parent trial were allocated to one of four parallel groups: (1) active tDCS + active MBM, (2) active tDCS + sham MBM, (3) sham tDCS + active MBM, or (4) sham tDCS + sham MBM. They underwent 10 20-minute sessions of anodal tDCS (active or sham) simultaneously with MBM (active or sham). WOMAC measures were secondary outcomes in the parent trial. Linear mixed-effects models, adjusted for baseline demographic and clinical characteristics, compared changes in WOMAC total and subscores (pain, stiffness, and physical function) across groups immediately (10 days) and three months post-intervention.

The sample was predominantly female (69.0%). Among females, only the active tDCS + active MBM group showed significantly greater reductions in WOMAC total scores-particularly in physical function-compared to the sham tDCS + sham MBM group immediately post-intervention (p = .049). No significant immediate effects were observed among males across WOMAC outcomes. No persistent effects of active tDCS + active MBM were observed at three months in either sex.

Although digital home-based tDCS paired with MBM may improve knee-specific symptoms, this effect was observed only among females and was short-term. Furthermore, findings should be interpreted cautiously given the sex imbalance.