For example, regional and global decreases in brain viscoelasticity have been observed in Alzheimer’s disease[20][21] and multiple sclerosis.[22][23] It has been found that as the brain ages, it loses its viscoelastic integrity due to degeneration of neurons and oligodendrocytes.[24][25] A recent study looked into both the isotropic and anisotropic stiffness in brain and found a correlation between the two and with age, particularly in gray matter.[26]