The impact of transcranial direct current stimulation on brain network connectivity and topology in post-stroke cognitive impairment patients: a resting-state fMRI study.

Abstract

Background: Post-stroke cognitive impairment (PSCI) is a common and severe consequence of ischemic stroke (IS) that significantly affects patient outcomes. Transcranial direct current stimulation (tDCS) has shown promise in enhancing cognitive function in IS patients, but its underlying mechanisms are not fully understood. This study investigates the effects of tDCS on brain functional connectivity and network topology using resting-state functional magnetic resonance imaging (rs-fMRI).

Methods: In this double-blind study, sixty-five IS patients with PSCI were randomly assigned to either the tDCS or control group. Rs-fMRI data were acquired before and after the intervention. We analyzed functional connectivity (FC) and graph theory-based topological properties. Cognitive performance was assessed using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). RESULTS AFTER: treatment, both groups showed improvements in MMSE and MoCA scores, with the tDCS group demonstrating significantly greater improvements (p < 0.05). In the tDCS group, FC significantly increased between four pairs of brain regions (p < 0.05, FDR-corrected). Additionally, Global Efficiency (E_g) significantly improved (p < 0.05, FDR-corrected), and this improvement positively correlated with enhancements in MMSE scores (r = 0.403, p = 0.037).

Conclusion: These findings suggest that tDCS improves cognitive function in PSCI by altering brain network connectivity and topological organization, providing neuroimaging evidence to support its therapeutic mechanisms.