Comparative analysis of acoustic features of spontaneous swallowing sounds between the young and the elderly

Objective To observe the features of spontaneous swallowing sounds of both the young and the elderly. Methods One hundred healthy individuals were randomly divided into an elderly group (60-85 years old) and a youth group (19-30 years old), each of 50 (25 male and female individuals). Both groups were measured with regard to their neck circumference (neck circumference around the thyroid cartilage level) and body mass index (BMI). Spontaneous swallowing sounds were detected for 20 minutes on the thyroid cartilage below the left side of trachea. By using RavenPro1.5.0, the swallowing sounds were segmented, tagged and calculated in terms of the spontaneous swallowing frequency per minute (SPM), swallowing duration, energy consumption, duration of half energy consumption and proportion of half energy consumption duration. All data were finally analyzed using R3.4.0. Results There was no significant difference in the average neck circumference between the youth group and the elderly group [(34.31±3.45) cm versus (33.95±3.00)cm] (P=0.5789). The BMI of the youth group was significantly lower than that of the elderly group [(21.97±2.65)kg/m2 vs (23.43±2.89)kg/m2]. The SPM of the elderly group was significantly lower than that of the youth group [(0.39±0.34) /min vs (0.91±0.51)/min, P<0.0001]. The length of swallowing, the energy consumption per swallowing and the duration of half energy consumption of the elderly group (0.92±0.29 seconds, 76.88±9.82 dB and 0.43±0.24 seconds) were significantly higher than those of the youth group (0.84±0.26 seconds, 75.43±8.93 dB and 0.38±0.19 seconds). However, no significant differences were found in the proportion of half energy consumption duration in the whole swallowing sound duration (P=0.6859). Conclusions Compared with the young, the frequency of spontaneous swallowing decreased and the swallowing duration prolonged significantly in the elderly. Key words: Swallowing; Aging; Acoustic analysis; Spontaneous swallowing frequency; Presbyphagia