Predictors of Pharyngeal Dysphagia in Patients with Parkinson's Disease

Background: Diagnosis of pharyngeal dysphagia in patients with Parkinson's disease is often difficult as reliable screening methods are lacking so far and clinical examination fails to adequately assess the pharyngeal phase of swallowing. Objective: To identify clinical predictors indicating the presence of pharyngeal dysphagia in patients at risk. Methods: We examined pharyngeal dysphagia in a large cohort of patients with Parkinson's disease (n = 200) divided in three clinical subtypes (tremor-dominant (TD), mainly bradykinetic (BK) and early postural instability and gait difficulty PIGD)) by using flexible endoscopic evaluation of swallowing. ANOVA-multivariance analysis and following t-tests as well as binary logistic regression analysis were performed to detect group differences and to identify clinical predictors for dysphagia. Results: Statistically significant differences were found in the dysphagic group: age, male gender, disease duration, stage of the disease, Levodopa equivalent dose and higher scores on the Unified Parkinson's disease rating scale III and II, item 7. The PIGD subtype was affected more frequently than the TD and BK subtype. In a logistic regression model higher age (>63.5 years p < 0.05) and Levodopa equivalent dose (>475 mg, p < 0.01) were identified to be independent predictors for the presence of pharyngeal dysphagia. Conclusion: Particularly patients with an age > 63.5 years and a daily Levodopa equivalent dose >475 mg show an increased risk for pharyngeal dysphagia. These findings may partly be influenced by presbyphagia but are likely to represent disease progression. The PIGD subtype seems to be a risk factor due to more pronounced dyscoordination of oropharyngeal muscle movements.