Figure Reconsidering the classification of dementia

Schematic diagram of common dementias depicts proposed alternative classification of dementia. Alzheimer disease (AD) and vascular dementia (VaD) fall on a continuous spectrum of disease, composed of a gradient of features of both AD and VaD (center panel; see text for detailed discussion). Neurodegenerative mechanisms play a greater role on the left side of the spectrum (upper panel). The impact of subcortical lesions of cerebral small-vessel disease increases to the right of the spectrum (lower panel). Note white matter hyperintensities on FLAIR sequences (left), lacunar lesions on T1-weighted sequences (arrowheads, center), and cerebral microhemorrhages on gradient-echo sequences (arrowheads, right). These silent brain lesions may, in part, mediate the risk of dementia associated with vascular risk factors.