Cerebrovascular disease and dementia.

Cerebrovascular disease is a major contributor to later-life dementia, accounting for up to 20% of cases of dementia. Atherosclerotic and arteriolosclerotic mechanisms account for most of the burden of disease. Cerebrovascular disease may take several forms. Macrovascular disease in the form of large vessel and larger arteriole infarcts produce a wide spectrum of clinical syndromes. Single strategic infarctions, multiple bilateral infarctions and multiple lacunar infarctions can lead to cognitive dysfunction that spans a large range of both severity and type of cognitive deficits. Microvascular disease almost certainly plays a role in the pathogenesis of dementia. Small vessel disease, which is not evident radiographically, often coexists with macrovascular disease and also with Alzheimer's disease. Amyloid angiopathy is relevant in cognitive disorders in the elderly and causes microhaemorrhages and large haemorrhages. Other much less common aetiologies include vasculitides and CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy). Neuroimaging plays a critical role in the diagnosis of vascular dementia. There is no framework for rating the extent of cerebrovascular pathology that is validated against increasing cognitive impairment. Although advances in imaging have increased our recognition of cerebrovascular disease in the elderly, vascular dementia is still inadequately recognized in clinical practice.