Applicability of the Two-Step Thickened Water Test in Patients With Poststroke Dysphagia: A Novel Assessment Tool for Paste Food Aspiration

This study evaluated the clinical usefulness of the newly developed Two-Step Thickened Water Test (TTWT) in identifying patients with poststroke dysphagia at risk of aspiration of paste food. The study subjects were 110 poststroke patients (mean age, 73 ± 10 years). The TTWT comprises a bedside pretest (tongue protrusion, vocalization, voluntary cough, and dry swallow) and a direct swallowing test using 4 mL of thickened water. Fiberoptic endoscopic evaluation of swallowing determined the subject's ability to swallow the paste food. Based on the test results and endoscopic evaluation, we calculated the TTWT's sensitivity and specificity in identifying paste food aspiration. We also calculated these values when normal water was used instead of thickened water in a direct swallowing test. The prevalence of dysphagia for paste food was 41% in our study group. The sensitivity and specificity of the TTWT in identifying dysphagia for paste food was 93% and 88%, respectively. The specificity decreased to 78.5% when normal water was used, with no decrease in sensitivity. The test was completed in less than 10 minutes, with no adverse events in any subject. Our data suggest that the TTWT might be a useful assessment tool for evaluating the risk of paste food aspiration in patients with poststroke dysphagia.