Our cross-sectional findings extend previous work, indicating that the hippocampal FW index is a more significant predictor of cognitive performance than hippocampal volume.Ofori et al. (2019)also found that hippocampal FW values were associated with global PET AV45 and CSF Aβ1–42levels and not CSF p-tau and CSF t-tau, suggesting that the FW index may provide specific information about the earliest pathological process in AD. Here, MAPT is linked to Alzheimer disease.