Comparison of Validated Videofluoroscopic Outcomes of Pharyngeal Residue: Concordance between a Perceptual, Ordinal, and Bolus-Based Rating Scale and a Normalized Pixel-Based Quantitative Outcome

Purpose: This study compared the concordance between two validated videofluoroscopic pharyngeal residue outcome scales used in clinical and research settings: the Dynamic Imaging Grade of Swallowing Toxicity (DIGEST) and the Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) percent residue metric. Method: Two trained raters completed independent and blinded videofluoroscopic ratings of both DIGEST efficiency and ASPEKT percent pharyngeal residue outcomes for bolus trials of 5 cc Varibar thin liquid (n = 223), thin liquid comfortable cup sips (n = 223), and 5 cc Varibar thin honey (n = 223). Spearman's rho and Kruskal-Wallis analyses were performed for each bolus type. Results: Significant associations between DIGEST and ASPEKT pharyngeal residue outcomes were noted for 5 cc thin (r = 0.54, p < 0.001), cup sip thin (r = 0.41, p < 0.001), and 5 cc thin honey (r = 0.60, p < 0.001) bolus trials. ASPEKT percent residue increased across worsening DIGEST efficiency ordinal scale levels, with a main effect for each bolus type. Post hoc analysis revealed significant differences in the ASPEKT percent residue values between each DIGEST pairwise comparison for the thin cup sip bolus trial and for each pairwise comparison except between the moderate-to-severe (less than half vs. majority) ordinal levels for the 5 cc thin and 5 cc honey bolus trials, p < 0.05. Conclusions: Perceptual, ordinal (DIGEST) and quantitative, pixel-based (ASPEKT) videofluoroscopic pharyngeal residue outcomes were associated in this data set of 669 bolus trials. Future research is warranted to confirm these results.