Cerebrospinal fluid (CSF), blood, and neuroimaging biomarkers can be analysed to detect or monitor the pathological changes in vivo caused by neurodegeneration.13,14 Neurofilament light chain (NfL) is a marker of axonal damage and neurodegeneration that is elevated in various neurodegenerative disorders, including AD.15-17 In AD, elevated levels of NfL have been associated with greater brain atrophy, in particular in brain regions affected by AD.18-20 However, the association between NfL levels and brain asymmetry is still unclear. Here, NEFL is linked to Alzheimer disease.