MAPT and Brain atrophy: The reduction in the levels of CSF proteins in patients with iNPH may result from the facilitated metabolic product drainage (Xie et al., 2013), dysfunction of CSF fluid dynamics (Herukka et al., 2015), interstitial fluid disorder in the glymphatic system (Iliff et al., 2012), and blockage of Aβ and tau protein outflow to the ventricular space induced by brain atrophy (Graff-Radford, 2014).