Quantifying Pharyngeal Residue Across the Adult Life Span: Normative Values by Age, Gender, and Swallow Task

Purpose: We quantified pharyngeal residue using pixel-based methods in a normative data set, while examining influences of age, gender, and swallow task. Method: One hundred ninety-five healthy participants underwent a videofluoroscopic swallow study following the Modified Barium Swallow Impairment Profile (MBSImP) protocol. ImageJ was used to compute Normalized Residue Ratio Scale and the Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) pharyngeal residue measures. Reliability was established. Descriptive statistics were performed for all residue measures. Inferential statistics were performed using ASPEKT total scores (i.e., %C2-4(2)). Logistic regression models explored predictors of residue versus no residue. Generalized linear mixed models explored predictors of nonzero residue. Spearman rho explored relationships between ASPEKT total residue scores and MBSImP Component 16 (Pharyngeal Residue) scores. Results: Majority of swallows (1,165/1,528; 76.2%) had residue scores of zero. Residue presence (%C2-4(2) > 0) was influenced by age (more in older [F = 9.908, p =.002]), gender (more in males [F = 18.70, p <.001]), viscosity (more in pudding, nectar, and honey [F = 25.30, p <.001]), and volume (more for cup sip [F = 37.430, p <.001]). When residue was present (363/1,528 = 23.8%), amounts were low (M = 1% of C2-4(2), SD = 2.4), and only increasing age was associated with increased residue (F = 9.008, p =.007) when controlling for gender and swallow task. Increasing residue was incremental (0.01% of C2-4(2) per year). As ASPEKT total residue values increased, MBSImP Component 16 scores also increased. Conclusions: Pharyngeal residue amounts were very low in healthy adults. Residue presence can be influenced by age, gender, and swallow task. However, when present, the amount of pharyngeal residue was only associated with increasing age.