Plasma Neurofilament Light Chain in memory clinic practice: evidence from a real-life study

OBJECTIVE: To explore plasma neurofilament light chain (NfL) as a biomarker for diagnosis and staging of cognitive impairment, in a large cohort with assessments performed in clinical practice. METHODS: Retrospective, cross-sectional, monocentric study, from a tertiary memory clinic. Patients underwent cerebrospinal fluid core Alzheimer’s disease (AD) biomarker evaluation using ELISA or Elecsys methods, and plasma NfL analysis using the single molecule array technology. The patients’ biomarker data were examined for associations with: i/cognitive status ii/presence of neurodegenerative disease and iii/diagnostic groups. Differences in NfL were tested using analysis of variance (ANOVA). RESULTS: Participants (N= 558, mean age= 69.2±8.8, 56.5% women) were diagnosed with AD (n=298, considering dementia and MCI stages), frontotemporal dementia (FTD, n=57), Lewy body disease (LBD, n=40, considering MCI and dementia stages), other neurodegenerative diseases (OND, n=53, e.g Supranuclear Palsy, Corticobasal degeneration), non-neurodegenerative cognitive impairment (NND, n=97, e.g vascular lesions, epilepsy or psychiatric disorders) or neurological controls (NC, n=53). Mean plasma NfL (log, pg/mL) levels were higher in neurodegenerative than non-neurodegenerative disorders (1.35±0.2 vs 1.16±0.23, p<0.001), higher in all diagnostic groups than in NC (1.06 ± 0.23) p<0.001), and associated with the stage of cognitive impairment (p<0.001). DISCUSSION: Plasma NfL may be considered as a clinical-decision support tool, to help distinguish neurodegenerative from non-neurodegenerative disorders.