Rationale for the Study Purpose Dementia is a clinical syndrome due to multiple aetiologies, of which Alzheimer disease (AD) and Vascular Dementia (VaD) are the two most common. Dementia represents the advanced stage of a syndrome spectrum of cognitive impairment, an age-associated neurodegenerative condition that includes ageing related cognitive disorder (aka age-associated memory impairment or subject memory impairment, i.e. memory loss without other cognitive problems and are within normal limits given the person's age), and Mild Cognitive Impairment (MCI), a clinical entity that includes memory and cognitive impairment but no significant functional disability to meet threshold criteria for diagnosis of dementia. Of note, MCI is considered a prodromal state of dementia that increases the risk of subsequently developing dementia.