Maximal hyoid excursion in poststroke patients

Reduced maximal hyoid excursion has been suspected as one of the primary physiologic causes of aspiration after a stroke. Vertical and anterior displacement of hyoid excursion is critical to epiglottic closure for airway protection and the opening of the upper esophageal sphincter (UES). Without these carefully timed and well-executed components, the bolus cannot pass safely through the pharynx. The purpose of this study was to evaluate vertical and anterior displacement of the hyoid bone during oropharyngeal swallowing in two groups of subjects: (1) 16 stroke patients who aspirate before or during the swallow (aspirators), and (2) 33 stroke patients who do not aspirate (nonaspirators). Means and standard deviations for anterior and vertical displacement were analyzed for 5- and 10-ml thin-liquid boluses using the ImageJ program (136 swallows). A two-way analysis of variance (ANOVA) was run with group and volume as independent variables. There was no significant difference between the two groups for vertical or anterior displacement. Maximal anterior displacement of the hyoid bone was slightly longer in nonaspirators than in aspirators. Aspiration before and during the swallow may be related more to the triggering of pharyngeal swallow than to the maximal extent of hyoid excursion.