Background: Tongue activity plays a crucial role in both oral and pharyngeal phases of swallowing. In this study, maximum lingual isometric and swallowing pressures were quantified in two groups of healthy men to investigate possible age effects on performance. Magnetic resonance images of the brain were also obtained to examine the relationship between age-related anatomical changes and swallowing function.
Methods: Pressures were recorded at three lingual sites (tip, blade, and dorsum) during a maximal isometric task and during saliva swallows. Task order was randomized, and subjects performed three trails per placement site. Additionally, t2-weighted MRIs were obtained on 9 of the 10 young subjects (mean age = 25 years) and all 15 older subjects (mean age = 75 years).
Results: Maximal isometric pressures were significantly greater for younger subjects at the tongue blade site (p = .002), whereas peak swallowing pressures remained similar across both age groups. Within-subject comparisons of maximum isometric to swallowing pressures, a measure of reserve capacity, revealed reduced difference scores at the tongue blade in the older group (p = .02). Older subjects exhibited significantly more cerebral atrophy (p = .001) and greater incidence of periventricular white matter lesions (p = .0001) than did younger subjects.
Conclusions: While swallowing pressures remain similar across the life span, overall pressure reserve declines with age. The implications are: (a) older people may be working harder to produce adequate swallowing pressures, and (b) age-related illness may put geriatric patients at higher risk for dysphagia, thus further complicating recovery.