Relationships among Speech Intelligibility, Chewing Ability and Depression in Older Adults

Abstract

Objectives: Due to anatomical and physiological changes, older adults often experience impaired speech intelligibility and reduced chewing ability which are frequently accompanied by depression. However, little research has been conducted to demonstrate the relationships between these measures.The aim of this study was to identify the overall relationships among speech intelligibility, chewing ability, and depression in accordance with orofacial functions in the elderly. Methods: Twenty-one healthy older adults (10 males; 11fe-males) participated in this study.The functions of lip, cheek, tongue, and soft palate, as well as chewing ability including regularity, frequency, duration and velocity measures, speech intelligibility and depression by Geriatric Depression Scale-Short Form were measured. Results: Most participants had normal orofacial functions, speech intelligibility, chewing ability and no signs of depression. Tongue strength was significantly correlated with range and velocity of the tongue movement and puffed cheek. Lip closure was not significantly related to other orofacial functions. The puffed cheek was significantly correlated with age. Speech intelligibility and chewing regularity had similar relationships and regression analysis results with orofacial functions. The velocity of the tongue movement was the only measure that correlated with and explained depression. Conclusion: Because speech and chewing share similar anatomical structures and overlapping neurophysiology, speech intelligibility and chewing had similar relationships with orofacial functions. Reduced speech and chewing ability can limit social activity and participation, which may eventually cause depression in older adults. Further research is necessary to explore the relationships between various variables affected by aging to better understand the older population.