UCHL1 and Parkinson disease: The aim of the present study was to test whether plasma neurofilament light chain (NF-L), total tau (t-tau), ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), fatty acid-binding protein 3 (FABP3), and phosphorylated tau (p-tau) can be used as prognostic biomarkers in PD.