Reduced pharyngeal constriction is associated with impaired swallowing efficiency in Amyotrophic Lateral Sclerosis...

Swallowing inefficiency is a prevalent but understudied problem in individuals with Amyotrophic Lateral Sclerosis (ALS). Although reduced pharyngeal constriction has been identified as a mechanism contributing to swallowing inefficiency following stroke, this relationship has not been empirically tested in the ALS population. This study sought to characterize profiles of swallowing efficiency in a sample of ALS patients and investigate relationships between pharyngeal constriction and swallowing efficiency.

Twenty-six adults with ALS underwent videofluoroscopic swallowing studies, involving 3 mL-thin, 20 mL-thin, and 3 mL-pudding boluses. Full-length recordings were segmented into bolus clips and randomized for analysis. We recorded the total number of swallows per bolus and obtained normalized pixel-based measures of pharyngeal constriction area and post-swallow residue in the vallecular and pyriform sinuses. Linear mixed models with Spearman's correlations were used to determine relationships between pharyngeal constriction and swallowing efficiency, with added factors of bolus volume and thickness.

Individuals with ALS demonstrated reduced pharyngeal constriction and increased vallecular and pyriform sinus residue, compared to norms. Reduced pharyngeal constriction had a significant effect on the presence of vallecular and pyriform sinus residue as well as the number of swallows per bolus. Increased bolus thickness was associated with increased vallecular residue, while increased bolus volume was associated with reduced pharyngeal constriction. Results were significant at P < 0.05.

Our results suggest that reduced pharyngeal constriction is a significant physiological parameter related to swallow inefficiency in ALS. Future work is needed to corroborate these preliminary results and investigate factors to mitigate such impairments.