Research criteria for subcortical vascular dementia in clinical trials

Vascular dementia (VaD) incorporate different vascular mechanisms and chang es in the brain, and has different causes and clinical manifestations. Vari ation in defining the cognitive syndrome, vascular etiologies, and brain ch anges in current clinical definitions of VaD has caused that different defi nitions used identify different prevalence, groups of subjects, as well as types and distribution of brain lesions. Thus current criteria for VaD sele ct an etiologically and clinically heterogeneous group. This definitional h eterogeneity may have been a factor for negative results in prior clinical VaD trials. An alternative for clinical drug trials is to focus on subcorti cal (ischemic) VaD, which incorporate two small vessel clinical entities "B inswanger's disease" and "the lacunar state". It comprises small vessel dis ease as the primary vascular etiology, lacunar infarct(s) and ischaemic whi te matter lesions as the primary type of brain lesions, and subcortical loc ation as the primary location of lesions. The subcortical clinical syndrome is the primary clinical manifestation, which definition still requires add itional empirical data. The subcortical VaD is expected to show a more pred ictable clinical picture, natural history, outcome, and treatment responses .