Gastric-filling ultrasonography to evaluate gastric motility in patients with Parkinson's disease.

"Conflict of interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest."

"The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the Medical Research Project of Chengdu Municipal Health Commission (2021041), Sichuan Collaborative Innovation Center for Aging and Elderly Health Project Fund (YLZBZ2016), the Sichuan Applied Psychology Research Center Project (CSXL-212A19), the Research Fund for the Key Laboratory of Development and Regeneration in Sichuan Province (SYS19-04), and Sichuan Provincial Geriatrics Clinical Medical Research Center Special Research Fund (SCLNZX201804)."

"Clinical Trial Registration https://www.chictr.org.cn/showproj.html?proj=126304."