NEFL and Parkinson disease: Similarly, NfL cut-off value in serum of 14.8 pg/ml (assessed by the Simoa approach) allows a clear discrimination (AUC = 0.91) between PD patients and those with atypical forms of parkinsonism (MSA and PSP), yielding a sensitivity of 86% and a specificity of 85% (Marques et al., 2019).