NEFL and Alzheimer disease: However, NfL is a non-specific marker of neuro-axonal injury and increased sNfL concentrations have been observed in various conditions that primarily affects different parts of the nervous system such as cortical atrophy in Alzheimer’s disease, atrophy of the basal ganglia, brainstem, and cerebellum in multiple system atrophy, and peripheral nerve injury in Guillain-Barré syndrome26–29.