Validation of the Normalized Laryngeal Constriction Ratio in Normal and Disordered Swallowing

Abstract

Purpose The timing of laryngeal vestibule closure (LVC) is important for airway protection during swallowing. However, it is unknown whether the extent of LVC contributes to airway protection. The goal of this study is to validate the extent of LVC via a measure called laryngeal constriction ratio (LCR). Methods A retrospective analysis of videofluoroscopic swallows was conducted on 38 stroke participants and 40 healthy controls. The LCR was calculated by deriving a size‐normalized area of airspace from a 1) maximum closed laryngeal vestibule and a 2) maximum open laryngeal airspace (at rest). Airway invasion severity was derived via the Penetration–Aspiration Scale score. Results Six hundred forty‐nine videofluoroscopic swallows were analyzed. A mixed model analysis revealed a statistically significant mean difference between the normalized laryngeal constriction ratios of healthy individuals (mean (m) = 0.003) versus older dysphagic patients (m = .026) (P = 0.001), quantifying less closure in older patients with dysphagia. Additionally, swallows with airway compromise had a statistically worse LCR when compared to swallows without airway compromise (P = 0.001). Conclusion The normalized LCR might be a valid fluoroscopic surrogate measure for LVC and, furthermore, airway compromise during swallowing. By investigating spatial measurements in the laryngeal vestibule during safe and unsafe swallows, the LCR provides a direction for further research to allow for critical examination of the physiology relating to closure degree in order to precisely detect and treat abnormalities during swallowing. Level of Evidence 4 Laryngoscope, 130:E190–E198, 2020

Swallowing kinematics and submental muscles activation during a newly designed maneuver called Mouth Open Swallowing Maneuver: A comparative study

“…However, inter-rater reliability was poor only for the vertical laryngeal movement of the THM. Although our results were largely compatible with the literature, the ICCs of some data were lower than those reported in other studies [ 35 , 64 , 65 ]. The potential margin of error in the interpretation of the hyolaryngeal kinematic analysis for vertical laryngeal movement of the THM should be taken into consideration.…”

“…Anterior-inferior point of the hyoid, the posterior-superior point of the subglottic air column, and the anterior-inferior point of C2 and the anterior-inferior point of C4 were marked for each image. During the tasks, the anterior-inferior point of the hyoid and the posterior-superior point of the subglottic air column were used for the initial position of the hyoid and larynx, and their positions were determined relative to the anterior-inferior point of C4 [34][35][36] (Fig 3). The initial position of the hyoid and larynx for MOSM was The diameter measurement of the coin was used to convert pixels to mm.…”

The American Broncho‐Esophagological Association Position Statement on Swallowing Fluoroscopy

“…Objective measures of timing, displacement, and luminal area are useful to compare normal from abnormal physiologic components of swallowing (Table IV). [89][90][91][92][93][94] Quantitative measures also help track a patient's improvement across time. Novice clinicians can be trained to reliably and quickly interpret VFSS using quantitative measures with high fidelity compared to experts.…”