Reliability and validity of the Standardized swallowing assessment among community-dwelling older adults in China

Oropharyngeal Dysphagia (OD) has become a public health issue and early screening has practical significance. The Standardized Swallowing Assessment (SSA) is a clinician-driven, simple, and efficient screening tool but has yet to be validated in Chinese communities.

This study aimed to cross-culturally adapt and validate the SSA in Chinese community-dwelling older adults and explore its optimal cut-off value.

The SSA was cross-culturally adapted according to a 5-stage process. Reliability included internal consistency, inter-rater reliability, and test-retest reliability. Cronbach's alpha was used to assess its internal consistency. The other reliability analyses were conducted using Pearson's correlation. Validity analysis included convergent and concurrent validity. For the convergent validity, the correlation between the SSA and Penetration-Aspiration Scale (PAS) or 10-item Eating Assessment Tool (EAT-10) was analyzed using Spearman's correlation and Mann-Whitney U tests. For concurrent validity, the association between the gold standard and the SSA was analyzed using Kruskal-Wallis and Mann-Whitney U tests. Receiver Operating Characteristic (ROC) analysis was used to explore the optimal cutoff value.

A total of 466 and 79 Chinese community-dwelling older adults were included in the first and second assessments, respectively. The Cronbach's coefficients for the total scale and each step were >0.7. The Pearson correlation coefficients were >0.8 for test-retest reliability (n = 79) and >0.9 for inter-rater reliability (n = 143), indicating excellent temporal stability and consistency across different raters. There were significant correlations between the SSA and both the EAT-10 (r > 0.5, p < 0.001) and PAS (r > 0.4, p < 0.001). There were significant differences in the SSA scores between the participants with the EAT-10 ≤ 3 and those with the EAT-10 > 3 (p < 0.001), or those with the PAS ≤ 3 and those with the PAS > 2 (p < 0.001). The Kruskal-Wallis test showed significant differences in the SSA scores across clinical severity (H = 142.388, p < 0.001). The optimal cutoff value was found to be 21.0 to distinguish healthy individuals from OD patients (C-index = 0.801, sensitivity = 0.983, specificity = 0.610), and to be 28.0 to differentiate mild OD from moderate-to-severe OD (C-index = 0.875, sensitivity = 0.914, specificity = 0.736).

The SSA showed good reliability and validity among community-dwelling older adults in China, and the optimal cutoff values were 21.0 and 28.0.