The first book on vascular dementia (VD) is more than 450 years old; nevertheless epidemiology, signs and symptoms, pathogenesis, prevention and therapy of VD are currently discussed more than ever. The clinical research uses several types of diagnostic criteria of VD (e.g. ICD-10, DSM-IV, NINCDS-AIREN, and ADDTC) which may identify different patient groups in the samé cohort. Sensitivity and specificity of tho-se criteria are not very high, results are therefore easily misinterpreted. The situation is complicated by fre-quent oceurrence of Alzheimeťs disease (AD) in conjunction with VD. VD as AD are clinical and neuropathological continua with subliminal and clinical evolution and possible, probable and definite diagnosis. The samé problém burden with clinical diagnostic criteria charges neuropathological diagnosis too: the practice and interpretation us not identical in different laboratories. Most frequent neuropathology in VD is a conjunction of cerebral embolism with large and small vessel disease resulting in „infarets large and small" and/or Binswangeres disease. Less frequent causes of VD are sporadic and familial cerebral amyloid angiopathy, CADASIL and vasculitides. Cerebral amyloid angiopathy accompanies AD in about 90% ca-ses; vascular encephalopathy is therefore common in AD too. Behaviour disturbances in VD are due to focal damage of cerebral cortex and white matter and due to more diffuse damage of white matter. Focal neurological signs and symptoms and damage of cognition, e.g. of executive functions, memory, attention and praxia thus manifest.

        Key words: vascular dementia, epidemiology, pathogenesis, diagnostic criteria, brain-behaviour correlation.