Bilateral Cerebellar Intermittent Theta Burst Stimulation Enhances Swallowing Function and Cortical Reorganization in Patients With Subacute Stroke: A Randomized Single-Blind Controlled Trial

Intermittent theta burst stimulation (iTBS) may enhance cortical excitability and induce neuroplastic changes through specific pulse patterns. This study aimed to investigate whether bilateral cerebellar hemisphere iTBS improves swallowing function in patients with subacute stroke and promotes reorganization of brain networks. In this sham-controlled, single-blind, randomized trial with blinded outcome assessment, both groups initially underwent conventional swallowing therapy including oropharyngeal training and Shaker exercises; 64 patients with subacute stroke with dysphagia received either active iTBS or sham-iTBS interventions. The stimulation parameters were 100% resting motor threshold, 50-Hz intraburst frequency, 5-Hz interburst frequency, and 1200 pulses per session. Swallowing function was assessed using the Standardized Swallowing Assessment (SSA) and Penetration-Aspiration Scale (PAS) at baseline and after a four-week intervention period. Functional near-infrared spectroscopy (fNIRS) was used to evaluate resting-state functional connectivity and task-induced cortical activation patterns. Both groups showed significant improvements in SSA and PAS scores after treatment (p < 0.05). However, the iTBS group exhibited significantly greater reductions in SSA and PAS scores than did the sham group (p < 0.05). fNIRS analysis revealed enhanced activation in the prefrontal cortex (PFC) and strengthened functional connectivity between the PFC and key regions, including the primary somatosensory cortex (S1), primary motor cortex, and right premotor cortex (RPM) in the iTBS group (p < 0.05). Notably, improvements in SSA scores correlated positively with strengthened functional connectivity between the RPM and left PFC (LPFC), in addition to between the LPFC and left premotor cortex (LPM) (p < 0.05). Bilateral cerebellar iTBS effectively enhances swallowing function in patients with subacute stroke, accompanied by increased interregional functional connectivity and heightened cortical excitability. The observed correlations between clinical improvements and specific connectivity patterns suggest that RPM-LPFC and LPFC-LPM pathways may represent key neuromodulatory targets for swallowing rehabilitation in this population. The Chinese Clinical Trial Registry number for the study is ChiCTR2300071303.