Correlation between swallowing and diaphragmatic functions in stroke patients with hemiplegia: a cross-sectional observational study.

Swallowing and diaphragmatic functions share neural regulatory pathways and require synchronous assessment. Patients who have had a stroke are susceptible to many complications, of which dysphagia and diaphragmatic dysfunction are particularly common. To compare the distribution and severity of swallowing function in stroke patients with and without diaphragmatic dysfunction, and to explore the correlation between swallowing and diaphragmatic functions. This cross-sectional observational study among 102 Chinese stroke patients with hemiplegia was conducted in August 2022 to December 2024. Data collection was completed in the first 48 h following admission, including sex, age, post-stroke duration, stroke type, stroke region, hemiplegia side, nasogastric feeding, and pneumonia. The patients were stratified into two groups by the presence or absence of diaphragmatic dysfunction, which was assessed by diaphragmatic ultrasound with a threshold of diaphragm thickening fraction (TFdi) < 20%. We compared the distribution and severity of different swallowing functions using the Modified Barium Swallow Study Impairment Profile (MBSImP) and the Penetration-Aspiration Scale (PAS) by Videofluoroscopic Swallowing Study (VFSS) between the two groups. Significant differences were found between the two groups in the oral and pharyngeal phases of the MBSImP (p < 0.003), including hold position/tongue control, bolus preparation/mastication, bolus transport/lingual motion, oral residue, initiation of the pharyngeal swallow, anterior hyoid motion, pharyngeal stripping wave, and pharyngeal residue (p < 0.003). In contrast, there were no significant differences between the two groups in some components of the MBSImP including lip closure, soft palate elevation, laryngeal elevation, epiglottic movement, laryngeal closure, pharyngeal contraction, and tongue base retraction (p > 0.003). The severity of swallowing physiological impairment by MBSImP between the two groups, including the oral phase, pharyngeal phase and total MBSImP scores showed significant differences (p < 0.003). By contrast, the distribution and severity of penetration and aspiration risk by PAS showed no statistically significant difference between the two groups (p > 0.003). TFdi was negatively correlated with grades of Water Swallowing Test, the oral phase, pharyngeal phase and total MBSImP scores (rs = -0.327 to -0.300, p < 0.003). Whereas no significant correlations were found between TFdi and pneumonia, nasogastric feeding and the PAS scores (p > 0.003). Patients with diaphragmatic dysfunction exhibited a higher proportion of swallowing physiological impairment in the oral and pharyngeal phases, along with greater severity of such impairments. Diaphragmatic function was correlated with swallowing function, but the correlation was weak and of uncertain clinical significance.