Brain-Swallowing Network Modulation: Neurorestoration by Bilateral Cerebell ar iTBS and Laryngeal Elevation Training in Post-Stroke Dysphagia

Background Previous studies have shown that pharyngeal elevation training can improve swallowing function in stroke patients, but the central nervous system interventions have limited effects. Intermittent theta burst stimulation (iTBS) applied to bilateral cerebellar hemispheres may enhance cortical excitability. However, the efficacy and underlying mechanisms of combining bilateral cerebellar iTBS with real-time biofeedback-guided pharyngeal elevation training for post-stroke dysphagia remain unclear. Objective This study investigates, for the first time, the combined effect of bilateral cerebellar iTBS and biofeedback-guided pharyngeal elevation training on swallowing function and cortical activity in stroke patients during the recovery phase.Methods:Forty-two stroke patients with dysphagia were enrolled based on hospital electronic screening; 3 dropped out, and 1 ceased due to condition change, another transferred hospitals, and 1 withdrew voluntarily, leaving 42 participants. They were randomly assigned to three groups (n = 14 each): Control (conventional rehabilitation), Sham-iTBS + SET, and Active-iTBS + SET. The latter two groups received additional interventions: Sham or active bilateral cerebellar iTBS combined with swallowing exercises. Swallowing function was assessed using the Standardized Swallowing Assessment (SSA) and Penetration-Aspiration Scale (PAS) before and after 4 weeks of treatment. Functional near-infrared spectroscopy (fNIRS) recorded cortical activation during tasks and resting-state functional connectivity.Results:After 4 weeks, all groups exhibited significant improvements in SSA and PAS scores (P < 0.05). Compared to the control, both Sham-iTBS + SET and Active-iTBS + SET showed superior improvements (P < 0.05), with the Active-iTBS + SET group outperforming the Sham group (P < 0.05). fNIRS revealed that the Active-iTBS + SET group significantly activated the right prefrontal cortex (RPFC) and premotor areas (PM), enhancing interhemispheric and intra-network functional connectivity, including between the PFC and other regions, and between M1 and PM (P < 0.05). Local node connectivity was also increased (P < 0.05). Improvements in SSA scores correlated positively with activation in RPM and RPFC (P < 0.05). Conclusion Bilateral cerebellar iTBS combined with pharyngeal elevation training significantly improves swallowing function in post-stroke dysphagia patients, associated with increased activation of the right prefrontal cortex and premotor areas, and enhanced cortico-cortical connectivity. The RPM region may serve as a potential neural target for cerebellar iTBS in stroke rehabilitation.