 Brain age delta is a measure of biological brain aging that can be derived from structural neuroimaging and is associated with markers of neurodegeneration and apophore status. It is also linked to plasma neurofilament light, which is a marker of neurodegeneration. This suggests that brain age delta may be a useful tool for identifying individuals who are at increased risk of developing dementia due to accelerated biological brain aging. This article was authored by Irene Completer Merrill, Marina Garcia Pratt, Gregory Aperto and others.