Preliminary Study of the Relationship Between Age and Gender using Sounds Generated from the Nostrils and Pharynx During Swallowing in Healthy Subjects

Although many studies have evaluated swallowing using sounds from the pharynx, few studies have evaluated it using sounds from the nostrils. Therefore, in this study, we placed two microphones near the nostrils and pharynx and recorded sounds produced while swallowing five grams of solid jelly. The participants included 16 healthy volunteers (eight in their early twenties (22-24 years old; younger group) and eight early elderly (66-74 years old; elder group), four males and four females in each group) over eight trials. We then examined the peak sound pressure levels of the nostrils and pharynx waveforms and investigated the time lags between the sounds generated by the nostrils and pharynx in each subject. As a result, although the time lags varied across the subjects, the minimum time lags observed in the elder group (0.32 – 0.78 s) were significantly longer than those of the younger group (0.04 – 0.44 s. $F_{1:15}$ = 30.10, $p \lt 0.05$, repeated two-way ANOVA), and the maximum time lags observed in the female subjects were significantly longer (1.04 – 2.30 s) than those of males (0.20 – 1.43 s. $F_{1:15}$ = 5.57, $p \lt 0.05$, repeated two-way ANOVA). It was suggested that measuring the sounds from both the pharynx and nostrils during swallowing helps in evaluating the swallowing function with aging, and considering gender differences.