Throughout the lifespan, common variations in systemic health and illness contribute to alterations in vasculature structure and function throughout the body, significantly increasing risk for cardiovascular and cerebrovascular disease (CVD). CVD is a prevalent cause of mortality in late life; it also promotes brain alterations, contributing to cognitive decline and, when severe, vascular dementia. Even prior to diseased states, individual variation in CVD risk is associated with structural and functional brain alterations. Yet, how cumulative asymptomatic alterations in vessel structure and function contribute to more subtle changes in brain tissue integrity and function that emerge in late life is unclear. Finally, vascular risk factors are associated with the clinical progression of neurodegenerative diseases such as Alzheimer’s disease (AD); however, recent theory posits that vascular degeneration may serve a contributory role in these conditions. This chapter reviews how lifespan changes in vascular health contribute to degenerative changes in neural tissue and the subsequent development of cognitive impairment and/or vascular dementia. It first discusses associations between vascular risk factors and cognition and also how declining vascular health may lead to cognitive impairment and dementia. Next, it identifies basic aspects of cerebrovascular anatomy and physiology sustaining tissue health and discusses how vulnerabilities of this system contribute to neurodegenerative changes. Finally, it reviews evidence of vascular contributions to AD and presents ideas for future research to better understand the full spectrum of cerebrovascular contributions to brain aging, cognitive decline, and dementia.
Risk Factors for Cognitive Impairment in Fragile X-Associated Tremor/Ataxia Syndrome
