There is overwhelming evidence to suggest that the neuropathology of Alzheimer's disease (AD) extends beyond amyloid plaques and neurofibrillary tangles. There is a clear overlap between the pathology of AD and vascular dementia (VaD), but the relationship is different for different types of vascular lesion. Cerebral amyloid angiopathy (CAA) and degeneration of the microvasculature are probably intrinsic to the AD process, whilst ischaemic white matter disease and areas of infarction are largely independent of AD pathology, but result in additional cognitive deficits and reduce the threshold of AD pathology necessary for the emergence of a clinical dementia syndrome.