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 Workstation^TM 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.

Coordination of respiration and swallowing: functional pattern and relevance of vocal folds closure

CONTEXT: Breathing and swallowing coordination, despite the expressive number of study, remain as theme deserving further research. OBJECTIVE: To identify a coordination pattern between swallowing and the natural breathing pause that occur in association with it (swallowing apnea) and also the relevance of the vocal folds closure in this process. METHODS: Sixty-six adults, male and female, including normal health people, post-laryngectomy individuals and patients with digestive complaints without dysphagia were analyzed. The respiratory air flux interruptions produced by wet requested swallows and dry, requested and spontaneous swallows, were registered using thermo and piezoelectric receptors coupled to synectics medical manometry equipment, using Polygram upper 4.21 software. The results were analyzed with the Chi-square (3×2) and (2×2) nonparametric independency test with P = 0.05. RESULTS: Swallowing apnea is a preventive breathing stop that start just before and stay present during all deglutition pharyngeal phase. It is a well coordinated phenomena that occur as pattern in association with low elastic resistance of the lung, on the expiratory final phase until inspiration initial phase. This breathing stoppage it is usually followed by a short expiraton preceding a new breathing cycle. The swallow apnea and vocal folds closure are both independents mechanisms. CONCLUSION: It is possible to suppose that in the subconscious condition, swallowing apnea is integrated under coordination of the same control mechanism that also involves the elastic resistance of the lung.

The Development of Swallowing Respiratory Coordination

Research exists that evaluates the mechanics of swallowing respiratory coordination in healthy children and adults as well and individuals with swallowing impairment. The research program summarized in this article represents a systematic examination of swallowing respiratory coordination across the lifespan as a means of behaviorally investigating mechanisms of cortical modulation. Using time-locked recordings of submental surface electromyography, nasal airflow, and thyroid acoustics, three conditions of swallowing were evaluated in 20 adults in a single session and 10 infants in 10 sessions across the first year of life. The three swallowing conditions were selected to represent a continuum of volitional through nonvolitional swallowing control on the basis of a decreasing level of cortical activation. Our primary finding is that, across the lifespan, brainstem control strongly dictates the duration of swallowing apnea and is heavily involved in organizing the integration of swallowing and respiration, even in very early infancy. However, there is evidence that cortical modulation increases across the first 12 months of life to approximate more adult-like patterns of behavior. This modulation influences primarily conditions of volitional swallowing; sleep and naïve swallows appear to not be easily adapted by cortical regulation. Thus, it is attention, not arousal that engages cortical mechanisms.