MAPT and Apathy: Apathy tends to emerge later in the pre-dementia disease course, relative to affective symptoms and irritability/impulse dyscontrol symptoms,32 both of which occur more frequently pre-dementia than apathy.33 Furthermore, there might be slightly different effect sizes for biomarker associations with different MBI domains, dependent on the time course of domain emergence relative to the deposition of amyloid and the phosphorylation of tau.