Pathophysiology of Swallowing Dysfunction in Parkinson Disease and Lack of Dopaminergic Impact on the Swallow Function and on the Effect of Thickening Agents

Abstract

(1) Background: The effect of dopaminergic treatment on swallowing response in patients with Parkinson’s disease (PD) suffering oropharyngeal dysphagia (OD) is not understood. Aim: To characterize OD pathophysiology in PD and to assess whether dopaminergic states affect swallow function and the effect of thickeners. (2) Methods: Fifty patients with PD (40 evaluated in OFF/ON states) and 12 healthy volunteers (HVs) were evaluated with videofluoroscopy (VFS) to assess the swallowing biomechanics and kinematics of the swallowing response at three different shear-viscosities (p < 0.05). An LVC ≥ 260 ms cutoff predicted unsafe swallow (sensitivity ≥ 0.83, specificity ≥ 0.57, AUC = 0.80) in PD. Increasing bolus viscosity improved deglutition safety but increased oropharyngeal residue. There were no differences in swallowing between the OFF/ON states. (4) Conclusions: In initial PD stages, oropharyngeal swallow response is severely delayed, while mildly impaired swallow safety improves with increasing bolus viscosity, which increases residue. Dopaminergic treatment does not affect swallowing or the therapeutic effect of thickeners.

Keywords

• oropharyngeal dysphagia
• Parkinson’s disease
• oropharyngeal swallow response
• thickening agents
• dopamine
• shear viscosity