Association between swallowing muscle mass and dysphagia in older adults: A case-control study

Swallowing function is formed by the synergistic, coordinated, and complex movements of approximately 30 muscles. However, There is no study on which one(s) of these muscles can predict the possibility of dyspfagia.

The purpose of this study was to investigate whether there is a relation between dysphagia and ultrasonographic measurements of swallowing muscles mass, and to determine which muscle mass would predict the possibility of dysphagia.

This prospective and controlled study was performed on 87 older people (aged >65 years). Clinical (Eating assessment tool-10 and The Gugging Swallowing Screen test), endoscopic, electrophysiological (dysphagia limit and swallowing intervals), and ultrasonographic (masseter [MM], genioglossus [GGM], geniohyoid [GHM], myohyoid [MH] and anterior digastric muscles [ADM]) evaluations were performed on all patients. The relationship between ultrasound measurements and demographic/swallowing characteristics and presence of dysphagia were investigated.

The muscle mass measurement which was associated with dysphagia was contracted masseter muscle. In terms of diagnostic performance, the sensitivity was the highest in GHM (92.3%) and the specificity was the highest in contracted MM thickness (90.3%). The probability of dysphagia increases from 54% to 80-89% with a decrease in contracted MM thickness, and the probability of dysphagia increased from 48% to 72% with a decrease in contracted GGM thickness. In addition, the highest AUC level was detected in contracted MM and contracted GGM muscles. Moreover, it was determined that the risk of dysphagia increased from 9.6 to 14.1 times with one unit decrease in muscle thickness in contracted MM muscles, and the risk of dysphagia increased 9.1 times with one unit decrease in contracted GGM muscles.

Decreased swallowing muscle mass in older adults are independent risk factors for dysphagia. Especially the decrease in the thickness of the contracted MM increases the possibility of dysphagia at high rate.