Background: Parkinson's disease (PD) is a major cause of disability. We aimed to assess the benefit of ultrasonography of the vagus nerve (VN) to compare between PD and healthy controls as well as to deliver reference values of nerve cross sectional area (CSA).
Materials And Methods: We performed a systematic search on Medline (PubMed), Scopus, Embase, and Web of Science, up till July 25, 2022.