Effects of the Validity of a Prior Notice on Drink Swallowing

―A Study Based on Cervical Auscultation and Surface-Electromyography―

Abstract

[Purpose] The aim of this study was to investigate the possible effects of spoken prior notice on drink swallowing.

[Subjects] The subjects were two groups: 11 younger participants ranging in age between 20 and 30 years old (mean age of 21.7, 1 male ＆ 10 females), and 8 older participants ranging in age between 65 and 75 years old (mean age of 68.4, 3 males ＆ 5 females).

[Method] Swallowing of apple juice, Aojiru (grass) juice, or water with or without spoken prior notice, was measured using surface electromyography and cervical auscultation.

[Results] Regardless of age, the maximum suprahyoid muscle activity significantly decreased when the drink was ingested without spoken prior notice. The interval between the onset of swallowing sound and the onset of infrahyoid muscle activity significantly shortened when the anticipation given by the prior notice was contradicted in the older participants.

[Conclusion] The results suggest that swallowing is affected by spoken prior notice. This phenomenon can be used for dysphagia rehabilitation.