Dysphagia in Alzheimer’s disease: a systematic review

Abstract

Dysphagia is described as a highly relevant comorbidity of Alzheimer’s disease (AD). However, there is a scarcity of studies aiming at the characteristics and progression of dysphagia. Objective: The objective of this study was to identify the specific characteristics, progression, and prevalence of dysphagia in AD. Methods: Publications were searched in the PubMed (MEDLINE), EBSCO, ScienceDirect, and BASE databases. Critical appraisal and evidence-level analysis were conducted using the Joanna Briggs Institute and Effective Public Health Practice Project’s (EPHPP) tools. Results: A total of 26 studies were reviewed. Symptoms begin in the early stage of AD, as oral phase impairments, and progress to pharyngeal symptoms and swallowing apraxia in the later stages of AD. Dysphagia progresses, as AD, along a continuum, with severity depending on individual variability. There were no studies found on prevalence. Conclusions: Dysphagia is a complex and important comorbidity in AD that impacts the quality of life. No recent publications on prevalence may imply that is not being coded as a potential cause for pneumonia deaths in AD.

Dysphagia and dementia: a ‘double dilemma’

“…Alzheimer's disease, frontotemporal, Lewy body), impaired circulation (vascular) and other factors that lead to a loss of nerve cells and their connections in the nervous system [2]. Resulting alterations in structures of the cortex and brainstem, and communication among them, are associated with progressive stages of the condition [3 ▪▪ ]. Though memory loss and cognitive impairments related to cortical changes are frequently considered as early hallmarks of dementia, recent evidence based on MRI data suggests that brainstem areas may also be affected in early stages of Alzheimer's disease [4 ▪ ].…”

“…Other swallowing behaviors in elderly individuals who may appear to be healthy should generate immediate concerns. Mira [3 ▪▪ ] has recently described inefficient mastication and airway clearance difficulties likely to result in frequent coughing or choking as indications of dysphagia in early-stage, hospitalized Alzheimer's patients. In our experience, these behaviors are not characteristic of normal aging in individuals with intact dentition and no swallowing-related comorbidities and, therefore, should trigger further assessment.…”

“…In moderate-to-advanced stages of dementia, increasing neurocognitive difficulty has been reported to interfere with food recognition and oral sensation. Difficulty preparing a bolus in the oral cavity, impaired opening of the upper esophageal sphincter, increasing and copious amounts of postswallow residue, and persistent aspiration before and after, as well as during swallow, have also been reported [3 ▪▪ ]. Increasing dyscoordination, or apraxia, of swallow function accompanying cortical and subcortical deterioration will eventually produce an inability to eat safely and effectively on one's own.…”

Pre‐hospitalization dysphagia and feeding tube placement in nursing home residents with advanced dementia

“…Although dysphagia was formerly considered a late-stage sequela of dementia, 3 emerging evidence has demonstrated biomechanical swallowing changes such as reduced laryngeal and hyoid elevation and prolonged laryngeal vestibule closure develop in the mild stage of the disease and accelerate with disease progression. 4,5 Further infections such as urinary tract infections and respiratory infections, which are common in patients with dementia, 2,6,7 may result in a functional decline in nursing home (NH) residents 8 potentially impacting the ability to eat safely. 9 Given the incidence of eating difficulties in patients with dementia, an important decision becomes how to address swallowing and nutritional concerns during the disease course.…”

“…Difficulty eating, also referred to as dysphagia, is noted to occur in up to 86% of persons with advanced dementia, 2 placing it among the most prevalent functional impairments endured by persons living with dementia. Although dysphagia was formerly considered a late‐stage sequela of dementia, 3 emerging evidence has demonstrated biomechanical swallowing changes such as reduced laryngeal and hyoid elevation and prolonged laryngeal vestibule closure develop in the mild stage of the disease and accelerate with disease progression 4,5 . Further infections such as urinary tract infections and respiratory infections, which are common in patients with dementia, 2,6,7 may result in a functional decline in nursing home (NH) residents 8 potentially impacting the ability to eat safely 9 …”