Influence of age and bolus size on swallowing function: basic data and assessment method for care and preventive rehabilitation.

Objective numerical data on swallowing function are needed to aid in eating and swallowing intervention and preventive rehabilitation. Using noninvasive methods, the influences of age and differences in size of water bolus on laryngeal activity and respiratory activity were examined in healthy young and older women. Swallowing function was influenced by age and bolus size. Influence of bolus size was recognized only in duration of laryngeal movement in younger women, with no apparent influence in older women. Results for older women were thought to be related to declines in swallowing function with the physiological aging of respiratory and swallowing muscles. In the future, noninvasive methods need to be developed for evaluating function and therapeutic effects against swallowing function impairment and to provide objective numerical data for health insurers.