Frequency-specific cortical swallowing-network responses following neuroengineering-guided individualized multichannel tDCS

Background Neuromodulatory interventions for dysphagia are increasingly explored as adjunctive rehabilitation strategies, yet their efficacy may be limited by non-individualized stimulation protocols and insufficient consideration of network-specific brain dynamics. Advances in neuroengineering now enable individualized targeting based on functional neuroimaging and computational modeling, offering the potential for precision neuromodulation of swallowing-related brain networks. Methods We investigated whether individualized multichannel transcranial direct current stimulation (mc-tDCS), optimized using magnetoencephalography (MEG)-derived target localization, MRI-based finite-element head modeling, and a distributed constrained maximum intensity (D-CMI) optimization framework, modulates the cortical swallowing network. In a randomized sham-controlled crossover design, eight healthy adults underwent three stimulation conditions: low-intensity mc-tDCS (1.5 mA), high-intensity mc-tDCS (4.0 mA), and sham stimulation. Swallowing-related cortical activity was assessed before and after stimulation using MEG source reconstruction of event-related desynchronization during uncued voluntary swallowing and a visually cued swallowing task requiring precise timing. A repeated-measures Dose × Task × Time model tested the hypothesized interaction separately in five frequency bands, with Holm correction across bands. Results No Dose × Task × Time interaction was significant after Holm correction across the five frequency bands (all adjusted p ≥ 0.274). Within-condition pre–post analyses identified alpha- and beta-band changes after 1.5-mA stimulation during challenged swallowing and a low-gamma change after 4.0-mA stimulation during uncued swallowing. Challenged-task timing accuracy increased over time, without significant Dose or Dose × Time effects. Conclusions This study demonstrates the feasibility of integrating individualized MEG-based targeting, subject-specific head modeling, and optimized multichannel stimulation. The hypothesized Dose × Task × Time interaction was not significant. Exploratory within-condition pre–post differences were observed in alpha, beta, and low-gamma activity, but do not establish stimulation-specific effects. Larger controlled studies are needed to evaluate the physiological effects of this individualized approach.