Within-Bolus Variability of the Penetration-Aspiration Scale Across Two Subsequent Swallows in Patients with Head and Neck Cancer.

To compare two consecutive swallowing attempts to study if there is a difference in Rosenbek's penetration-aspiration scale (PAS) scores between the first and second swallowing attempt of the same bolus type in videofluoroscopic examination of swallowing (VFS). Additional aims include reflecting on which bolus sizes and consistencies are the most relevant to include in further studies for head and neck cancer (HNC) patients. The VFS for 38 patients curatively treated for HNC was studied. All included patients showed swallowing difficulties (PAS ≥ 2). The examination protocol included two swallows each of six different boluses: 3, 5, 10, 20 ml thin, 5 ml mildly thick, and 3 ml of extremely thick liquid. All boluses were compared between the first and second swallowing attempt with regard to PAS scores. No statistically significant differences in PAS were found between the first and second swallow for any of the boluses in this study on group level. For 20 ml thin and 3 ml extremely thick liquid, there were low Intra-Class Correlations, indicating a low within-bolus agreement. The greatest within-bolus differences were found for 20 ml thin, 5 ml mildly thick and 3 ml extremely thick liquid, which demonstrated high intra-individual coefficient of variation (0.458-0.759). The data of this study show a high within-bolus variability of the PAS score between two subsequent swallows for all different consistencies. In order to assess swallowing safety, the highest PAS score for each bolus type is suggested for use in studies of HNC patients.