A Retrospective Analysis of Swallowing Function and Physiology in Patients Living with Dementia

Dysphagia is commonly diagnosed in patients living with dementia, but we lack understanding of changes in swallowing physiology and the resulting relationship to impairments of safety and efficiency. The purpose of this study was to describe the pathophysiology of dysphagia in a retrospective sample of patients living with dementia. Videofluoroscopy data from 106 adults (mean age: 84) diagnosed with dementia were scored by blinded raters. Raters analyzed 412 thin liquid swallows for safety [Penetration-Aspiration Scale (PAS)], efficiency [% of (C2-C4)], timing [Pharyngeal Transit Time (PTT), Swallow Reaction Time (SRT), Laryngeal Vestibule Closure Reaction Time (LVCrt), Upper Esophageal Sphincter Opening Duration (UESO)], and kinematics (pharyngeal constriction). Impairment thresholds from existing literature were used to characterize swallowing. Chi-square tests and Pearson's correlations were used to determine associations between swallowing physiology and function. Compared to published norms, we identified significant differences in PTT, SRT, LVCrt, UESO, and degree of maximum pharyngeal constriction. Unsafe swallowing (PAS > 2) was seen in 17% of swallows. Clinically significant residue (i.e., % of (C2-C4) > 0.54 vallecular; > 0.34 pyriforms) was seen in most patients. Chi-square tests revealed significant associations between LVCrt and unsafe swallowing. There was a weak positive association between post-swallow residue in the pyriforms and poor pharyngeal constriction. Detailed analysis of swallowing physiology in this sample provides insight into the pathophysiological mechanisms associated with dysphagia in patients living with dementia. Further work is needed to explore additional bolus consistencies and to identify how physiology changes based on type and severity of dementia diagnosis.