The Relationship between Clinical Measures of Dysphagia, Self-Reported Symptoms, and Cognition in People with Parkinson’s Disease

Introduction: This cross-sectional study sought to examine the relationship between cognitive function and dysphagia-related outcomes in people with Parkinson’s disease (PD), describe how objective dysphagia measures relate to swallowing self-report, and identify potential cognitive predictors of dysphagia in people with PD. Methods: Fifty-two people with PD underwent prospective measurement of subjective (EAT-10 questionnaire) and objective (timed water- and cracker-swallowing tests) swallowing outcomes. These were compared to global cognitive scores extrapolated from neuropsychological tests completed within the same day or week. Bayesian regression models were constructed to assess the relationship between swallowing and cognitive outcomes, controlling for disease severity. Results: The majority of participants (71%) had normal cognition and 43% had EAT-10 scores, suggesting a risk of dysphagia. Findings revealed no relationships between cognition and objective or subjective swallowing outcomes. However, there was a main effect of water-swallowing time on dysphagia self-report (beta = 0.1, 95% credible interval CrI 0.04, 0.2), and an interaction between water-swallowing time, dysphagia self-report and cognition (beta = 0.1, 95% CrI 0.01, 0.2). Reduced cognition did not appear to be a risk factor for dysphagia in this study. Conclusion: Water-swallowing ability appears to impact how patients report their swallowing to a greater extent than cracker-swallowing; thus, it may be an important component to include in clinical assessment and post-treatment measurement. From a clinical perspective, dysphagia should not be ruled out in patients with intact cognition who deny swallowing changes, given a lack of evidence for a relationship between these variables. Future work in this area should include measures of depression, anxiety, and instrumental swallowing function.