An examination of factors related to aspiration and silent aspiration in older adults requiring long-term care in rural Japan

Swallowing disorders are a growing problem among the elderly in long-term care (LTC), and they can cause aspiration pneumonia. In order to detect swallowing disorders early, simple tools are needed to assess aspiration and silent aspiration (SA). To compile a sample of elderly people requiring LTC, and categorise them as having suspected aspiration and/or SA using simple screening tools. In addition, oral ability, severity of dementia, vital functions and nutritional status were compared in these groups. A total of 393 elderly people in LTC (89 men and 304 women; age ranging from 65 to 100 years) were included in the study. The modified water swallow test, cervical auscultation and cough test were used to assess swallowing function. The participants were categorised as having suspected aspiration and/or SA, and the following assessments were performed: (i) oral ability (lips function, tongue function, rinsing and gargling ability), (ii) dementia severity, (iii) vital functions and (iv) nutritional status. Suspected aspiration was apparent in 505% of patients, of which 240% had suspected SA. Those with suspected aspiration showed worsened oral ability, dementia severity, vital functions and nutritional status. Similarly, those with suspected SA showed worsened dementia severity, vital functions and nutritional status. Logistic regression analysis revealed that lip closure, lingual movement and rinsing ability were significantly associated with suspected aspiration. Dementia severity was the best predictor of suspected SA. Simple screening tools can be used to identify suspected aspiration and SA, which may facilitate early detection of aspiration pneumonia or swallowing disorder risk.