Follow-up Comparisons of Two Plasma Biomarkers of Alzheimer's Disease, Neurofilament Light Chain, and Oligomeric Aβ: A Pilot Study

Background and Objective: Recent evidence suggests that blood-based biomarkers might be useful for Alzheimer's disease (AD). Among them, we intend to investigate whether neurofilament light (NfL) and multimer detection system-oligomeric A beta (MDS-OA beta) values can be useful in screening, predicting, and monitoring disease progression and how the relationship between NfL and MDS-OA beta values changes. Methods: Eighty participants with probable AD dementia, 50 with mild cognitive impairment (MCI), and 19 with subjective cognitive decline (SCD) underwent baseline and follow-up evaluations of the Mini-Mental Status Examination (MMSE) and both plasma biomarkers. Results: Baseline MDS-OAss (p=0.016) and NfL (p=0.002) plasma concentrations differed significantly among groups, but only NfL correlated with baseline MMSE scores (r=-0.278, p=0.001). In follow-up, neither correlated with MMSE changes overall. However, in SCD and MCI participants (n=32), baseline MDS-OAss correlated with follow-up MMSE scores (r=0.532, p=0.041). Linear regression revealed a relationship between baseline MDS-OA beta and follow-up MMSE scores. In SCD and MCI participants, plasma NfL changes correlated with MMSE changes (r=0.564, p=0.028). Conclusion: This study shows that only in participants with SCD and MCI, not including AD dementia, can MDS-OAss predict the longitudinal cognitive decline measured by follow-up MMSE. Changes of NfL, not MDS-OAss, parallel the changes of MMSE. Further studies with larger samples and longer durations could strengthen these results.