Dysphagia and oropharyngeal bradykinesia in Parkinson's disease

Dysphagia is a manifestation of swallowing dysfunction frequently observed in Parkinson's disease (PD). It can lead to serious clinical consequences when the patient experience aspiration or chest infections. Even in less severe cases, dysphagia significantly affects patients' quality of life. Understanding the pathophysiology underlying PD-related dysphagia is important for proper classification and for objectifying swallowing abnormalities with clinical evaluation. This review explores the mechanisms of swallowing, the various aspect of swallowing abnormalities, and their impact on the quality of life of PD patients-especially in relation to impaired responses to levodopa-and discusses suggested therapeutic approaches. In our opinion, true dysphagia in PD is less common than often believed. Swallowing difficulties may reflect oropharyngeal and/or lingual bradykinesia. Hypokinesia, a hallmark motor symptom of PD, may affect swallowing reflex and result in prolonged pharyngeal reflex times due to slow, sequential muscle movements. Symptoms such ad difficulty swallowing, food retention, sensation of food in the esophagus, and the need to drink liquids to aid bolus transit are more indicative of bradykinesia than dysphagia. Therefore, swallowing abnormalities should be carefully assessed and properly classified, with tailored pharmacological treatment and dietary adjustments for each individual case.