The Role of Aspiration Amount on Airway Protective Responses in People with Neurogenic Dysphagia

Abstract

The aim of this study was to examine relationships between the presence vs. absence of an aspiration-related airway protective response (i.e., coughing or throat clearing) with aspiration amount, trial volume, disease diagnosis, and disease duration in people with neurologic disease. A secondary analysis was completed of flexible endoscopic evaluations of swallowing (FEES) in people with neurologic disease. Thin liquid boluses with endoscopically confirmed aspiration were included. Aspiration amount was measured for each trial using the visual analysis of swallowing efficiency and safety (VASES). Statistical analyses were used to (1) compare aspiration amount between swallows with vs. without an airway protective response and (2) examine if trial volume, disease duration, and disease diagnosis were related to the presence of airway protective responses when controlling for aspiration amount. 422 aspirated swallows across 86 FEES were analyzed. Of the 59 people who aspirated more than once, 66.1% exhibited variability in the presence vs. absence of an airway protective response. Statistical analyses revealed airway protective responses were significantly related to aspiration amount (p < 0.001; Marginal R² = 0.46) and disease duration (p = 0.036, L.R. = 4.35) but not trial volume (p = 0.428) or disease diagnosis (p = 0.103). The participants in this study were less likely to cough or throat clear when having smaller amounts of aspiration or longer disease durations. Future research is needed to examine if aspiration amount is related to airway protective responses in healthy adults and across other patient populations.

Keywords: Aspiration amount; Cough; Dysphagia; FEES; Silent aspiration; Swallowing.