Swallowing abnormalities and dyskinesia in Parkinson's disease.

Gastrointestinal abnormalities in Parkinson's disease (PD) have been known for almost two centuries, but many aspects concerning their pathophysiology have not been completely clarified. The aim of this study was to characterize the oropharyngeal dynamics in PD patients with and without levodopa-induced dyskinesia. Fifteen dyskinetic, 12 nondyskinetic patients, and a control group were included. Patients were asked about dysphagia and evaluated with the Unified Parkinson's Disease Rating Scale Parts II and III and the Hoehn and Yahr scale. Deglutition was assessed using modified barium swallow with videofluoroscopy. Nondyskinetic patients, but not the dyskinetic ones, showed less oropharyngeal swallowing efficiency (OPSE) for liquid food than controls (Dunnett, P = 0.02). Dyskinetic patients tended to have a greater OPSE than nondyskinetic (Dunnett, P = 0.06). Patients who were using a higher dose of levodopa had a greater OPSE and a trend toward a smaller oral transit time (Pearson's correlation, P = 0.01 and 0.08, respectively). Neither the report of dysphagia nor any of the PD severity parameters correlated to the videofluoroscopic variables. In the current study, dyskinetic patients performed better in swallowing function, which could be explained on the basis of a greater levodopa dose. Our results suggest a role for levodopa in the oral phase of deglutition and confirm that dysphagia is not a good predictor of deglutition alterations in PD. Copyright 2004 Movement Disorder Society.