NEFL and Alzheimer disease: The signal for CSF NfL levels was found to be highest for patients with FTLD (n = 56) compared to controls (n = 98, 1.38; 0.99–1.77), with a very small effect size for CSF NfL only to separate FTLD (n = 58) from AD (n = 99, 0.62; 95% CI 0.26–0.97) (Petzold et al., 2007).