Sarcopenia and Dysphagia

Abstract

Sarcopenia is attracting attention today because it is associated with life prognosis, but the definition of sarcopenia has not been established. Until now, muscle mass reduction was considered an indispensable element of sarcopenia, but in 2019 EWGSOP announced that sarcopenia must firstly involve reduced muscle strength, adding that both muscle mass and muscle quality are important. We must also recognize the differences between disuse syndrome and sarcopenia. Although increasing reports are emerging of dysphagia due to sarcopenia, it is important to understand that general muscle sarcopenia and sarcopenia of swallowing muscles are different. The muscle related to swallowing is the striated muscle, but it is embryologically close to the respiratory muscle derived from the branchial arch and has characteristics different from those of the limb skeletal muscles. The swallowing muscle is difficult to become disused because it is driven by respiratory input at rest. The only exception is the geniohyoid muscle, which is prone to sarcopenia. While it is important to understand the dysphagia caused by sarcopenia of the swallowing muscles, many diseases that cause dysphagia in the elderly are complicated with sarcopenia, complicating the pathophysiology.