Physiologic model of oropharyngeal swallowing revisited

Abstract

Objectives: Historical studies of oropharyngeal swallowing have used small boluses, unnatural means of bolus presentation, and temporal measures to differentiate normal vs abnormal function. This study set out to test the known physiologic model of oropharyngeal swallowing in 80 healthy volunteers in 4 age groups: group 1 (21–40 years; n = 20), group 2 (41–60 years; n = 20), group 3 (61–80 years; n = 20), group 4 (81+ years; n = 20) using larger bolus volumes during cup drinking. Methods: Simultaneous videofluorographic and respiratory airflow recordings were obtained during liquid swallowing. Factor analysis and multiple regression were used to support or refute the known model. Results: Analysis revealed a 3-factor model with nonage dependent variation in the sequence of timed physiologic components. The onset of the obligatory cessation in breathing was highly variable and could not be used to signal abnormality. The onset of hyoid excursion was highly predictive of the total pharyngeal swallow duration ( P < 0.01), yet was delayed by definition in the previous model without evidence of laryngeal penetration or aspiration. Expected differences in temporal pharyngeal events were not found when these normative data were compared to age-matched patients treated for head and neck cancer. Conclusions: These findings speak to the inadequacy of using temporal measurement as the sole means of swallowing assessment. Rather, valid and reliable tools are demanded that allow quantification of the functionality of the components of swallowing as they relate to patient outcomes. A validated measurement model under empirical test will be presented.