NEFL and Alzheimer disease: Of note, our estimates are higher than those seen in a similar-sized retrospective case series with pathologic confirmation in which 5 of 21 CBS cases (23.8%) had primary pathologic AD findings at postmortem.15 Alongside these phenotype-specific markers, our inclusion of data from a large PD cohort allowed us to confirm that the use of serum NF-L levels and cognitive screening scales may aid the early differentiation of PD from APS.33,34