Comparisons of Temporal Characteristics of Respiration and Swallowing Coordination between Young and Elderly

Objectives: The relationship between breathing and swallowing is very dynamic during swallowing and these are highly temporally coordinated to protect the airway. The ability to protect airways during swallowing deteriorates with aging. In this study, we attempted to compare the breathing-swallowing pattern and temporal change in the respiration and swallowing coordination between young and elderly adults in Korea.Methods: A total of 80 normal people, including 40 young and 40 elderly people participated in this study. For measurement of breathing and swallowing coordination, Digital Swallowing WorkstationTM was used during a 5 mL water swallowing task. Temporal parameters related to breathing-swallowing including AS (acoustic start), AP (acoustic peak), AD (acoustic duration), SAS (swallowing apnea or respiration pause start), SAD (swallowing apena duration), sES (submental sEMG start), sEP (submental sEMG peak), sED (submental sEMG duration). Additionally, DHI (Dysphagia Handicap Index) was evaluated for self-assessment of the degree of difficulty swallowing.Results: Older adults displayed delayed swallowing-related acoustic signal measurements, swallowing apnea measurements, surface EMG measurements, and delayed sequential coordination time of swallowing-related structures during swallowing. There were no significant differences according to gender. Furthermore, a significant positive correlation was observed between the total K-DHI scores and as well as swallowing apnea duration in the elderly.Conclusion: In the older population, the different breathing-swallowing pattern from that of young adults may increase the risk of dysphagia. In addition, swallowing delays due to aging can be an indicator of elderly swallowing disorders. Moreover, an increase in apnea time during swallowing may be a phenomenon that appears as a mechanism for airway protection in the elderly. However, the high correlation between apnea time and K-DHI score in the elderly may make it difficult to maintain respiration for a long time during swallowing as the respiratory function decreases due to aging, which may increase the risk of experiencing symptoms such as choking and affect the degree of subjective swallowing disorder. This suggests that even if classified as a normal elderly person without a pathological swallowing disorder, swallowing training is needed to prevent swallowing disorders and to enhance swallowing ability for older people with degraded swallowing-related abilities.