Clinical deficits of Alzheimer's disease with cerebrovascular disease and probable VaD.

Vascular dementia (VaD) describes dementia arising from cerebrovascular disease (CVD) and ischaemic brain injury, and relates to a number of different vascular mechanisms and clinical manifestations. The characterisation of brain lesions by neuroimaging analysis, and the study of their relation to clinical deficits such as cognitive and functional decline, are critical to the concept and treatment of VaD, and form an important part of widely used diagnostic criteria for this dementia type. For instance, the extent to which pathological brain lesions cause, compound or coexist with cognitive impairment is a major determinant of other clinical deficits, their nature and the rate of disease progression. Through numerous neuroimaging and epidemiological studies, VaD is now seen to encompass a heterogeneous group of clinical syndromes such as multiple-infarct (cortical) dementia, small-vessel (subcortical) dementia and, less commonly, dementia associated with strategic infarcts. Due to a large number of similarities in clinical symptoms, pathophysiological mechanisms, associated risk factors and neurochemical deficits between VaD and Alzheimer's disease, patients with coexistent Alzheimer's disease and CVD ('mixed' dementia) represent another important, but previously underestimated subgroup. This article reviews the clinical symptoms and neuroimaging findings most commonly observed in patients with VaD. Increased familiarity with the clinical picture of VaD should offer more hope of defining realistic treatment aims for future pharmacotherapy.