Deglutition in Advanced Age

Abstract

New Zealand’s population is ageing; it is forecast that more older adults will be living longer. Ageing is associated with increased health conditions, diseases, and medications, some of which cause swallowing problems (dysphagia). It is essential that clinicians understand swallowing function in healthy individuals in order to differentiate swallowing impairment from normal variability. However, previous studies are limited by poor representation of adults in advanced age (over 80 years old). The objective of this thesis is to investigate swallowing physiological changes in older age and their impact on function, activity, and participation. Swallowing changes in advanced age were summarised in a current opinion of recent literature and critically appraised in a systematic review using quantitative results from instrumental assessments. Three cross-sectional studies were conducted to investigate swallowing in three cohorts of older New Zealanders: healthy (65–99 years old, n = 65), hospitalised (65–100 years old, n = 52), and community-living (65–96 years old, n = 1020). Normative data (18–99 years old, n = 275) are presented for a new quantitative measure of post-swallow residue: the Bolus Clearance Ratio. Individuals over 80 years old demonstrated little residue, though many performed an additional swallow to clear oral residue, or metered the bolus, suggesting reduced swallow efficiency with age. Normative timing and displacement results were compared with hospitalised older adults who developed dysphagia during their stay but were admitted for unrelated reasons. Significant differences between the hospitalised cohort and healthy older adults indicate that swallowing dysfunction is not associated with ageing itself. Communityliving older adults without medical history known to affect swallowing reported normal swallowing status. Although the prevalence of dysphagia increases with age, swallowing problems are not an inevitable consequence of ageing. Quantitative analyses indicate overall subtle changes in swallowing physiology with age do not compromise swallow safety. Therefore, swallowing concerns should not be considered a sign of normal ageing and ignored. Future studies should plan to recruit adults of advanced age and adapt services to cater for our ageing population.