Epiglottic Retroflexion is a Key Indicator of Functional Recovery of Post-stroke Dysphagia

Abstract

Objective: To evaluate the longitudinal changes of swallowing kinematics based on videofluoroscopic swallowing studies (VFSSs) in subacute stroke patients grouped according to the method of dietary intake.

Methods: Sixty-nine subacute stroke patients who had taken at least 2 successive VFSSs were included. Subjects were allocated into 3 groups according to the degree of swallowing function recovery-not improved group (tube feeding recommended to patients at both studies), improved group (tube feedings recommended initially to patients and oral feeding recommended at follow-up study), and well-maintained group (oral feeding at both studies recommended to patients). Initial VFSS was performed during the subacute stage of stroke, 1 to 12 weeks after the onset of stroke, and follow-up VFSS was performed at least once. Kinematic variables were calculated by two-dimensional motion analysis of multiple structures, including the hyoid bone, epiglottis, and vocal cord. Changes of kinematic variables were analyzed in serial VFSSs.

Results: At the initial VFSS, the well-maintained group showed significantly larger angles of epiglottic folding than the not improved group, while at the follow-up VFSS, the improved and the well-maintained groups showed significantly larger epiglottic folding angles than the not improved group. The distribution of epiglottic folding angles was in a dichotomous pattern, and each cluster was related to the swallowing function.

Conclusion: This study showed that improved epiglottic folding angles are associated with the recovery of the swallowing process and suitability for oral feeding among various kinematic variables in subacute stroke patients.

Keywords: Deglutition; Epiglottis; Stroke; Swallowing.

Fig. 1.

Comparison of epiglottic folding angle between 3 groups at initial and follow-up studies. *p<0.05, **p<0.001 in Mann-Whitney test with Bonferroni correction.

Fig. 2.

Distribution of epiglottic folding angle at (A) initial study and (B) follow-up study. Both histograms show a definite dichotomous pattern of distribution. (C) Data from follow-up study of “improved” group and both studies of “well-maintained” group are gathered to show the distribution of epiglottic folding angle among patients suitable for oral feeding.

Fig. 3.

A scatter plot of the epiglottic folding angle at initial and follow-up studies. Vertical and horizontal auxiliary lines are at 51.41°. Nine out of 14 patients in “not improved” group have low angles of epiglottic folding, while 31 out of 34 patients of “well-maintained” group have high angles of epiglottic folding in both studies.

Fig. 4.

Change of diet in “improved” group patients between the initial and follow-up studies. Based on the change of epiglottic folding angle, the patients are grouped into 3 subgroups: subgroup 1, epiglottic folding angles of the 2 studies are lower than 51.41°; subgroup 2, epiglottic folding angle is lower than 51.41° in the initial study, but improved to higher range in follow-up study; subgroup 3, epiglottic folding angle is higher than 51.41° at the initial study. It shows that the higher epiglottic folding angle is associated with less limitation on a diet. ASHA NOMS, American Speech-Language-Hearing Association National Outcome Measurement System.