ABSTRACT
This pilot study used functional near-infrared spectroscopy (fNIRS) to examine brain activity in selected regions of the left motor and sensory cortex while doing swallowing-related tasks. Specifically, differences in cortical activation during normal saliva swallows, effortful swallows, and tongue pressing were investigated. Nine healthy, right-handed adults (5 female, 4 male; Age: 22-30 years) were recruited. The tasks included were (1) normal saliva swallowing, (2) effortful saliva swallowing, and (3) lingual pressing against the palate. Each task was completed three times in a block, for a total of five blocks. Blocks were randomized and presented with set time intervals using PsychoPy. Motor activity was highest during effortful swallows, followed by normal swallows, and lingual presses. Activation in the sensory region was not significantly different across tasks; however, effortful swallows elicited the highest mean peak activation. Our findings suggest that fNIRS can be a viable imaging method used to examine differences in cortical activity in the context of swallowing. Its applicability in future dysphagia research should be explored.
ABSTRACT
PURPOSE: Age-related changes to the swallowing mechanism, or presbyphagia, may put older adults at a higher risk for developing diseases and dysphagia. Maintaining swallowing functions could help prevent frailty and facilitate healthy ageing. This review summarises and appraises the effects of oropharyngeal exercises on the swallowing functions of healthy older adults without dysphagia. It is hypothesised that these exercises will strengthen and improve the structures and functions of the normal ageing swallow. METHOD: This review was reported according to the PRISMA 2020 guidelines. Five electronic databases (Medline, Embase, Cochrane Library, Web of Science, CINAHL) and Google Scholar were searched in June 2021. A rerun was done in January 2023. Study selection, data extraction, and quality assessment were done by two independent raters. RESULT: A total of 23 studies were reviewed. Meta-analysis was not conducted due to the heterogenous training protocols and outcomes. Majority (n = 21) had fair quality due to incomplete reporting. Exercises targeting oral structures were implemented the most (n = 15), followed by variations of the head lift (n = 4), and effortful swallow exercise (n = 1). Others implemented combined or multiapproach exercise studies (n = 3). Apart from surface electromyography findings, statistically significant improvements in oral and pharyngeal phase swallowing outcomes such as increased lingual isometric and swallowing pressures, bite force, muscle thickness, hyolaryngeal excursion, and upper oesophageal sphincter opening diameter were reported in 95% of the studies (n = 22). CONCLUSION: Collective evidence suggests that strength training for swallowing-related structures leads to increases in structural strength, endurance, and muscle mass. The effects of exercises on overall swallowing efficiency and safety remain unclear. Results should be interpreted with caution due to methodological limitations. Further research should examine the long-term effects of these exercises in preventing frailty and reducing the burden of dysphagia in older adults.
