Discriminant ability of the 3-ounce water swallow test to detect aspiration in amyotrophic lateral sclerosis

Abstract

Background: Given the need for quick and accurate dysphagia screening tools to optimize referral workflows and resource utilization in fast-paced multidisciplinary amyotrophic lateral sclerosis (ALS) clinics, we evaluated the discriminant ability of the 3 oz. water swallow test (WST) to detect aspiration in individuals with ALS.

Methods: A total of 212 paired 3 oz. WST (index test) and standardized videofluoroscopic swallow studies (reference test) were completed in individuals with a confirmed diagnosis of ALS. Blinded raters analyzed swallowing safety using the validated penetration-aspiration scale (PAS; non-aspirator: PAS < 6; aspirator: PAS ≥ 6). Receiver operating characteristic curve analysis, area under the curve (AUC), sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated.

Key results: Index test: 78 (36.8%) WSTs were scored as a fail and 134 (63.2%) as a pass.

Reference test: Aspiration was confirmed in 67 (31.6%) reference tests with 145 (68.4%) reference tests verified as having no aspiration. Sensitivity and specificity of the 3 oz. WST to detect radiographically confirmed aspiration was 55.2% and 71.7%, respectively (AUC: 0.635, PPV: 47.4%, NPV: 77.6%).

Conclusions & inferences: In this dataset, the 3 oz. WST did not demonstrate adequate sensitivity or specificity to detect aspiration in people with ALS as a stand-alone dysphagia screening tool.

Keywords: ALS; deglutition; deglutition disorders; dysphagia; neurodegenerative disease; screening; videofluoroscopy.