Evaluation of CSF neurofilament light chain levels as a routine biomarker in a memory clinic.

Systematic evaluation of biomarkers in representative populations is needed to validate their clinical utility. In this work, we assessed the diagnostic performance of cerebrospinal fluid neurofilament light chain (NfL) in a neurocognitive clinical setting. A total of 51 patients with different cognitive clinical syndromes and 11 cognitively normal individuals were evaluated in a memory clinic in Argentina. Clinical conditions included: Mild cognitive impairment (MCI, n=12), Dementia of Alzheimer's Type (DAT, n=14), Behavioral variant Frontotemporal dementia (bvFTD, n=13), and Primary Progressive Aphasia [logopenic (lvPPA, n=6), semantic (svPPA, n=2), and non-fluent (nfvPPA, n=4)]. We quantified CSF NfL and core Alzheimer's disease biomarkers using commercially available ELISA kits. Cortical thickness was analyzed on brain MRI scans from 10 controls and 10 patients. CSF NfL was significantly increased in MCI, FTD and DAT patients compared to controls (Kruskal-Wallis, p<0.0001). Interestingly, receiver operating characteristic (ROC) curve analysis showed the highest area under the curve (AUC) value when analyzing control versus bvFTD patients (AUC= 0.9441). Also, we observed a marginally significant correlation between NfL levels and left orbito-frontal cortex thickness in a small group of patients with FTD. Overall, our results further support CSF NfL as a promising biomarker in the diagnostic work up of bvFTD.