Definition and Concept of Vascular Cognitive Impairment

Abstract

Worldwide, it is estimated that approximately 35 million people had dementia in 2010. With the prevalence of this condition expected to double every 20 years, dementia remains an important public health challenge. These estimates along with the growing costs of contemporary medical care have heightened interest in this disabling and progressive condition. Alzheimer disease and vascular cognitive impairment account for almost 70% of all the dementias. These two entities were traditionally considered divergent disorders. However, autopsy studies and data obtained using state-of-the-art neuroimaging modalities demonstrate that these dementia subtypes commonly coexist in the elderly. There is substantial observational epidemiologic evidence that links vascular risk factors in midlife to Alzheimer disease in the elderly. In addition, neurodegeneration and atherosclerosis have a synergistic effect on cognitive decline. These observations have fueled the provocative idea that a substantial number of the dementia cases can be prevented by controlling traditional vascular risk factors. In this chapter, we review the epidemiology and the evolution of diagnostic criteria for dementia with special emphasis on vascular cognitive impairment. In addition, we discuss the contribution of vascular risk factors to neurodegeneration and novel strategies to prevent or delay cognitive decline.