PRPH and mild neurocognitive disorder: Plasma PRPH levels were significantly different (Kruskal–Wallis: chi‐squared = 70.4, df = 2, p = 5.55 × 10−16; Figure 1) in MND patients (1.49 ± 0.63 ng/mL), MND mimics (0.79 ± 0.34 ng/mL), and HCs (0.94 ± 0.44 ng/mL).