The single-site Austrian Stroke Prevention Study monitored a cohort of 335 adults with no obvious neurological disorder ranging in age from approximately 38 to 85 years over an approximately six-year period for serum NfL changes using a single-molecule array (Simoa assay) with UmanDiagnostics anti-core domain antibodies.38 Although median NfL levels were relatively similar among individuals in the fourth and fifth decades of this normal aging cohort, NfL rose non-linearly and demonstrated more variability in participants aged 60 and older. This evidence concerns the gene NEFL and nervous system disorder.