Repetitive saliva swallowing test: Performance in aspiration prediction

This retrospective study evaluates the performance characteristics of the Repetitive Saliva Swallowing Test (RSST), a widely used dysphagia screening tool known for its simplicity, safety, and high sensitivity in predicting aspiration during modified barium swallow studies (MBSS).

We analyzed data from 246 patients (197 men, 49 women; median age 62 years) who underwent MBSS between August 2021 and January 2023 at a medical center. The patients were grouped into head and neck cancer (n = 164), neurological disease (n = 47), and other conditions (n = 35). RSST was performed immediately before MBSS, recording the number of swallows in 30s. MBSS was conducted following the Modified Barium Swallow Impairment Profile™ protocol, evaluating 17 physiological swallowing parameters and generating Oral and Pharyngeal Impairment Scores. Swallowing safety were assessed using the Penetration-Aspiration Scale, while transit times were measured for thin barium boluses.

Using RSST count ≤2 as the cutoff, sensitivity for detecting aspiration during MBSS was 35.5 %, specificity 92.4 %, and accuracy 78.1 %. Sensitivity was the lowest in the cancer group (25.0 %) and the highest in other conditions (50.0 %). Optimal cutoffs were identified at RSST ≤3, ≤4, and ≤2, with an area under the receiver operating characteristic curve of 0.72.

Although RSST demonstrates low sensitivity for aspiration detection, its high specificity, simplicity, and safety make it suitable for large-scale screening in populations with relatively low dysphagia prevalence.