The semisolid bolus swallow test for clinical diagnosis of oropharyngeal dysphagia: a prospective randomised study

Contrary to clinical experience, clinical swallow tests are predominantly performed using water (water swallow tests, WST). In this study, we examine whether swallow tests performed using a bolus of semisolid food (bolus swallow test, BST) offer benefits. In a prospective, randomised, blind study, the results of a standardised saliva swallow test (SST), WST, BST, combinations of these tests and an endoscopic swallow test (FEES) in patients with oropharyngeal swallowing disorders of neurological (NEU) and non-neurological (NNEU) origin were compared. Sensitivity, specificity, test accuracy and inter-rater reliability were analysed. 62 patients (mean age = 64.68; range = 22–84) were included in the study (NEU = 40; NNEU = 22). A sensitivity of 70.7% (NEU = 70.3%, NNEU = 71.4%) and specificity of 82.5% (NEU = 92.3%; NNEU = 100%) were determined for the WST. The BST + SST was found to have a sensitivity of 89.6% (NEU = 66.7%; NNEU = 90.9%) and a specificity of 72.7% (NEU = 87.5%; NNEU = 90.9%). Analysis of test accuracy showed a statistically significant correlation between FEES and BST + SST. Only BST + SST exhibited statistically significant inter-rater reliability. BST in combination with SST was the sensitive clinical instrument for detecting aspiration both over the patient population as a whole and over the two sub-populations. Inter-rater reliability was found to be statistically significant. The results presented here demonstrate the benefit of semisolid food in investigating clinical dysphagia.