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

Timing of True Vocal Cords Closure for Safe Swallowing: A Review of 5 Studies Using 3D Analysis Using Computerized Tomography (CT)

Timely and complete laryngeal closure is critical for a successful swallow. Researchers have studied laryngeal closure, including true vocal cords (TVC) closure, closure of the arytenoids to the epiglottis base (laryngeal vestibule closure), and epiglottic inversion, but the most commonly available imaging tools have limitations that do not allow the study of these components individually. Swallowing computerized tomography (CT) has enabled three-dimensional dynamic visualization and quantitative evaluation of swallowing events providing a unique view of swallowing-related structures and their motion. Using CT, TVC closure can be visualized and evaluated on any plane or cross-section without being obscured by of laryngeal vestibule closure or epiglottis inversion. The current review summarizes the results of five papers evaluating the effects of bolus consistency and volume, posture, and age on TVC closure. The combined results of these studies suggest that TVC closure is responsive to oral sensory input based on bolus consistency and size and can be modulated in response to conditions perceived to increase the risk of airway invasion. These results are meaningful for dysphagia rehabilitation as it suggests that interventions to improve TVC closure are likely to enhance airway protection.

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

The aim of this study was to design a new maneuver called the Mouth Open Swallowing Maneuver (MOSM), and to compare swallowing kinematics and submental muscles activation (SMA) between MOSM and two current approaches used in dysphagia rehabilitation. Fifty healthy volunteers were asked to perform three repetitions of dry swallowing (DS) (control task), the MOSM, the Mendelsohn Maneuver (MM), and the Tongue-Hold Maneuver (THM) during videofluoroscopic swallowing study accompanied with simultaneous SMA recording. Swallowing kinematics were measured by frame-by-frame analysis on hyolaryngeal movement using ImageJ. Swallowing with maximum hyolaryngeal movement and SMA during these tasks was used for comparative analysis. Vertical movement of the hyoid during the MOSM was significantly greater than those observed during the DS and the THM (p<0.001, p<0.001). Horizontal movement of the hyoid during DS and the THM was significantly greater than that observed during the MM (p = 0.001, p = 0.001). Vertical movement of the larynx during the MOSM was significantly greater than those observed during DS, MM, and THM (p<0.001). There was no significant difference between tasks in horizontal movement of the larynx (p = 0.785). SMA during the THM was significantly greater than that observed during MOSM (p = 0.002). No significant difference was found between other tasks in terms of SMA (p>0.05). The MOSM as a newly designed maneuver was significantly superior to other maneuvers in increasing vertical hyolaryngeal movement. The THM has as much effect on hyolaryngeal movement as the MM. In this study, the MOSM was shown to be effective in increasing hyolaryngeal movement. ClinicalTrials.gov Protocol Registration and Results System (PRS); the clinical trial registration number (NCT05579041).

The American Broncho-Esophagological Association Position Statement on Swallowing Fluoroscopy

OBJECTIVES

To develop an expert consensus statement on the clinical use of swallowing fluoroscopy in adults that reduces practice variation and identifies opportunities for quality improvement in the care of patients suffering from swallowing impairment.

METHODOLOGY

A search strategist reviewed data sources (PubMed, Embase, Cochrane, Web of Science, Scopus) to use as evidence for an expert development group to compose statements focusing on areas of controversy regarding swallowing fluoroscopy. Candidate statements underwent two iterations of a modified Delphi protocol to reach consensus.

RESULTS

A total of 2184 publications were identified for title and abstract review with 211 publications meeting the criteria for full text review. Of these, 148 articles were included for review. An additional 116 publications were also included after reviewing the references of the full text publications from the initial search. These 264 references guided the authors to develop 41 candidate statements in various categories. Forty statements encompassing patient selection, fluoroscopic study choice, radiation safety, clinical team dynamics, training requirements, videofluoroscopic swallow study and esophagram techniques, and interpretation of swallowing fluoroscopy met criteria for consensus. One statement on esophagram technique reached near-consensus.

CONCLUSIONS

These 40 statements pertaining to the comprehensive use of swallowing fluoroscopy in adults can guide the development of best practices, improve quality and safety of care, and influence policy in both the outpatient and inpatient settings. The lack of consensus on some aspects of esophagram technique likely reflects gaps in knowledge and clinical practice variation and should be a target for future research. Laryngoscope, 133:255-268, 2023.