Effect of aging on oral and swallowing function after meal consumption

Background/purpose: Dysphagia may worsen due to fatigue of the infrahyoid and suprahyoid muscle groups as a result of repetitive swallowing during a meal. We investigated the hypothesis that meal consumption may reduce tongue strength and endurance in older adults (OAs). Methods: Tongue-palate pressure, oral diadochokinesis, repetitive saliva swallowing, and surface electromyography activity before and after a meal were measured in 23 young adults (YAs) and 23 OA volunteers. Results: There was a statistically significant difference in both tongue pressure and the number of voluntary swallows between YAs and OAs. Peak tongue pressure was significantly lower in OAs than YAs both before and after meal consumption. The most notable finding was that the first time interval (the time from test initiation to the beginning of the first swallow) was prolonged after meal consumption only in OAs, whereas the first time interval showed no difference between YAs and OAs before meal consumption with reference to the repetitive saliva swallowing test. The initiation of swallowing was prolonged by both meal consumption and aging; there was a significant interaction between these two factors. The number of repetitions of the monosyllable/pa/was statistically similar between YAs and OAs before meal consumption, but it was significantly lower in OAs after meal consumption. Conclusion: Aging leads to declining tongue pressure and motor function of the lips. It is possible that swallowing function declines in older individuals when meal consumption is prolonged, especially at the end of mealtime, as a result of their efforts in mastication and swallowing.