MAPT and Alzheimer disease: The biomarkers used to diagnose AD are therefore divided into two categories: (1) reflecting Aβ deposition, such as Aβ42 in cerebrospinal fluid (CSF) or Aβ PET; and (2) reflecting neuronal damage, such as CSF tau/p‐Tau, hippocampal or medial temporal lobe atrophy on MRI, and glucose hypometabolism on PET or SPECT.