Preliminary Exploration of Variations in Measures of Pharyngeal Area During Nonswallowing Tasks.

Abstract

Purpose: Age- and disease-related changes in oropharyngeal anatomy and physiology may be identified through quantitative videofluoroscopic measures of pharyngeal area and dynamics. Pixel-based measures of nonconstricted pharyngeal area (PhAR) are typically taken during oral bolus hold tasks or on postswallow rest frames. A recent study in 87 healthy adults reported mean postswallow PhAR of 62%(C2-4)², (range: 25%-135%), and significantly larger PhAR in males. The fact that measures were taken after initial bolus swallows without controlling for the presence of subsequent clearing swallows was identified as a potential source of variation. A subset of study participants had completed a protocol including additional static nonswallowing tasks, enabling us to explore variability across those tasks, taking sex differences into account.

Method: Videofluoroscopy still shots were analyzed for 20 healthy adults (10 males, 10 females, M_age = 26 years) in head-neutral position, chin-down and chin-up positions, a sustained /a/ vowel vocalization, and oral bolus hold tasks (1-cc, 5-cc). Trained raters used ImageJ software to measure PhAR in %(C2-4)² units. Measures were compared to previously reported mean postswallow PhAR for the same participants: (a) explorations of sex differences; (b) pairwise linear mixed-model analyses of variance (ANOVAs) of PhAR for each nonswallowing task versus postswallow measures, controlling for sex; and (c) a combined mixed-model ANOVA to confirm comparability of the subset of tasks showing no significant differences from postswallow measures in Step 2.

Results: Overall, PhAR measures were significantly larger in male participants; however, most pairwise task comparisons did not differ by sex. No significant differences from postswallow measures were seen for 5-cc bolus hold, chin-down and chin-up postures, and the second (but not the first) of two repeated head neutral still shots. PhAR during a 5-cc bolus hold was most similar to postswallow measures: mean ± standard deviation of 51 ± 13%(C2-4)² in females and 64 ± 16%(C2-4)² in males.

Conclusions: PhAR is larger in men than in women. Oral bolus hold tasks with a 5-cc liquid bolus yield similar measures to those obtained from postswallow rest frames.