Physiological Flow of Liquids Used in Dysphagia Management (Neuro)

For individuals with neurodegenerative conditions, such as Amyotrophic Lateral Sclerosis and Parkinson disease, swallowing impairment (i.e., dysphagia) is a common and serious symptom. Dysphagia places the affected individual at risk for secondary health consequences, including malnutrition and aspiration pneumonia, and negatively affects quality of life. Thickened liquids are commonly recommended for individuals with dysphagia, as they flow more slowly and reduce the risk of entry into the airway. However, there is limited understanding about how changes in liquid thickness modulate swallowing physiology in individuals with neurodegenerative conditions, and previous reports have shown that increased liquid thickness may contribute to the accumulation of residue in the throat. The purpose of this study is to explore swallowing physiology and function in individuals with neurodegenerative conditions, across five levels of liquid thickness (thin, slightly-thick, mildly-thick, moderately-thick, and extremely-thick), and to identify boundaries of "optimal liquid thickness", which maintain airway safety, without contributing to the accumulation of significant residue. Results from this study will help guide the clinical recommendations for thickened liquids in dysphagia management.