A Systematic Review of Physiological Changes in Swallowing in the Oldest Old

Age-related swallowing changes are well-researched in deglutology, usually distinguishing those over 60 years as older aged. World-wide, older adults are healthier and forecast to live longer: many over 85 years. It is necessary for clinicians to understand healthy swallowing changes in this 'oldest old' in order to appropriately manage swallowing complaints in older patients. This systematic review collated and critically appraised studies investigating swallowing changes in adults over 85 years using instrumental assessment. Criteria for inclusion were healthy subjects over 85 years. Exclusion criteria included studies focused on anatomy and oral processing. Studies published until December 2018 were retrieved from BIOSIS, CINAHL, Embase, Medline, and Scopus, totaling 2125 articles. During data screening, 64% of studies investigating age-related swallowing changes were excluded, as the oldest old were not recruited. After PRISMA screening, 44 articles met criteria. These were further reviewed for data extraction, bias and quality. Main quantitative age-related changes in swallowing included increases in delay in swallow onset, bolus transit times, duration of UES opening, pressure above the UES and UES relaxation pressure, and reduction in pressure at the UES. Few studies detected increased residue or airway compromise in the form of aspiration. Results were not easily comparable due to differences in age ranges, methods for deeming participants 'healthy', measures used to define swallowing physiology, and swallowing tasks. Age-related swallowing changes are identified that do not compromise safety. The oldest old are underrepresented in normative deglutition research. It is essential future studies plan accordingly to recruit those over 85 years.