Unlocking trunk potential after stroke: a novel approach combining transcranial direct current stimulation and core stability exercise: a randomized controlled trial

Impaired trunk control is a critical contributor to poststroke disability, as it undermines balance, mobility, and independence. Core stability exercises (CSEs) improve trunk function; however, their efficacy may be limited by post-stroke reductions in cortical excitability. Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulation technique that enhances neuroplasticity and may potentiate the effects of rehabilitation. To determine whether combining tDCS with CSEs improves trunk control, balance, and functional independence in chronic stroke survivors. In this single-blind randomized controlled trial, 60 participants with post-stroke hemiparesis were assigned to either a study group (n = 30) receiving anodal tDCS (2 mA, 20 min) over the ipsilesional primary motor cortex concurrent with CSEs or a control group (n = 30) receiving CSEs alone. Both groups underwent supervised sessions three times per week for 12 weeks. The primary outcome was the Trunk Impairment Scale (TIS). Secondary outcomes included the Postural Assessment Scale for Stroke (PASS), Berg Balance Scale (BBS), and Barthel Index (BI). Both groups improved significantly across all the outcomes (p < 0.001). The combined intervention produced greater gains than did CSE alone: TIS (+ 2.80 vs. +1.83, p = 0.005), PASS (+ 4.01 vs. +1.31, p = 0.001), BBS (+ 6.64 vs. +2.21, p < 0.001), and BI (+ 9.20 vs. +1.96, p < 0.001). Trunk improvements strongly predicted functional gains (ΔTIS vs. ΔBI, r = 0.72, p < 0.001). Simultaneous tDCS and CSEs significantly enhance trunk control, balance, and independence beyond the benefits of exercise alone, representing a promising strategy for post-stroke neurorehabilitation. Trial registration The trial was registered at ClinicalTrials.gov (Identifier: NCT06882213; registered on 12 March 2025). This study was retrospectively registered.