Swallowing in Parkinson's disease: How is it affected?

Objectives: The aim of this study was to evaluate the swallowing in patients with Parkinson's disease (PD) using comprehensive and multimodal methods.

Patients and methods: The present study was conducted on 120 patients and 60 controls between January 2017 and January 2018. All participants' demographic data were recorded, and the swallowing of the subjects was evaluated by using several methods, including clinic, electrophysiologic, endoscopic and ultrasonographic procedure. First, the swallowing functions of the patient and control groups were compared. Subsequently, the patients were divided into two groups as patients with (n = 63) or without (n = 57) dysphagia symptoms according to their clinical evaluation. Finally, the data of these three groups were compared.

Results: In comparison with healthy subjects, the swallowing evaluated by all diagnostic methods were affected in patients with PD. This effect was greater in patients with clinically symptomatic dysphagia. No difference was found between patients without dysphagia symptoms and healthy controls based on clinic, endoscopic and some electrophysiologic methods. Interestingly, thickness of all oral phase muscles in healthy controls were significantly higher than both dysphagic and non-dysphagic PD patients according to ultrasonography.

Conclusion: Although it is widely known that dysphagia symptoms in patients with PD usually occur in advanced stages and cause serious problems for patients, the present study establishes that swallowing functions may have been affected in early stage patients without dysphagia symptoms. Assessment of swallowing functions is important and should be also assessed in patients without dysphagia symptoms. Moreover, ultrasonographic method may be used in the diagnosis and follow-up of patients with PD.