Feasibility of combining tDCS with TMS-EEG to probe neuroplasticity in post-stroke aphasia

Increasing evidence suggests that transcranial direct current stimulation (tDCS) can enhance language outcomes in people with post-stroke aphasia. However, the neurophysiological mechanisms underlying these behavioral improvements remain insufficiently characterized.This crossover feasibility study examined the clinical and technical viability of integrating transcranial magnetic stimulation with electroencephalography (TMS-EEG) to characterize cortical excitability and network dynamics before and after real and sham tDCS in individuals with chronic post-stroke non-fluent aphasia.Eight participants were enrolled; four completed the full protocol, while four discontinued due to scheduling or technical constraints. The completers underwent eight weeks of anodal tDCS and language exercises. They tolerated the combined procedures well, with full adherence, no adverse events, and good-quality TMS-EEG recordings, confirming the protocol's feasibility.Cortical responses were quantified using global and local mean field power (GMFP, LMFP) and a regional complexity index. Behaviorally, modest language improvements were observed in two participants with Broca's aphasia. Neurophysiologically, heterogeneous modulations of cortical reactivity were observed across cases.These findings indicate that this multimodal protocol can be practically and safely implemented, with no adverse effects observed, while also underscoring logistical, technical, and clinical considerations for larger-scale studies designed to elucidate the neurophysiological mechanisms supporting tDCS-driven language recovery.