MAPT and early-onset autosomal dominant Alzheimer disease: The microstructural changes detected by DTI are thought to reflect several underlying pathological processes in Alzheimer's disease: (i) Demyelination of axons, leading to reduced FA and increased MD, (ii) Axonal loss, resulting in decreased directional diffusion of water molecules, (iii) Accumulation of amyloid-β and tau proteins, which may disrupt white matter integrity, and (iv) Neuroinflammation and oxidative stress, contribute to white matter damage.