The mouth-opening muscular performance in adults and elderlies with and without dysphagia: A systematic review and meta-analysis

Objectives: To characterize mouth-opening muscular performance (MOMP) in adults and elderly individuals with dysphagia and healthy controls. Methods: We searched the PubMed, EMBASE, CINAHL, Cochrane, Scopus, and Web of Science databases from inception to Jan. 26, 2023. Two independent researchers considered the titles, abstracts, and full texts of potentially eligible papers from 1451 search results. Twenty-five studies that evaluated mouth-opening maximal strength (MOMS) in healthy adults, elderly individuals, and patients with dysphagia met the inclusion criteria. Results: We found comparable, reliable values with significant sex differences in maximal mouth opening strength (MMOS) in the meta-analysis for healthy elderly patients (females 5.31 ± 0.47 kg vs. males 7.04 ± 0.70 kg; mean difference of 0.84 kg). Age has also emerged as an essential factor in reducing strength. There was a significant reduction in the MMOS score in the only study that compared dysphagic individuals to healthy elderly individuals. In another study, the MMOS score was comparable to the meta-analysis of healthy elderly individuals. Conclusions: Both sex and age play significant roles in the MMOS. There is no reliable data on the normal mouth-opening strength and endurance of healthy adults, patients with dysphagia, or individuals with other relevant clinical problems.