Ultrasound Subclinical Markers in Assessing Vascular Changes in Cognitive Decline and Dementia

Abstract

Aging is often associated with some cognitive impairment. Greater population life expectancy is one explanation for increased incidence of cognitive impairment cases. Large numbers of people with cognitive impairment and dementia is becoming one of the most important medical and social problems worldwide. Therefore, prevention of cognitive impairment is an imperative. Dementia includes a heterogeneous group of disorders, the most common being Alzheimer's disease and vascular dementia. Most cardiovascular risk factors, such as hypertension, diabetes mellitus, hypercholesterolemia, atrial fibrillation, and smoking, are not exclusively risk factors for vascular dementia, but also for Alzheimer's disease. Early changes in the blood vessel wall can be detected by early ultrasound screening methods which allow us to detect changes before the disease becomes clinically evident. Intracranial hemodynamics can be assessed by transcranial Doppler sonography (TCD), functional TCD with various functional tests, and TCD detection of cerebral emboli. Extracranial circulation (carotid and vertebral arteries) can be assessed by means of color Doppler flow imaging. Novel ultrasound technology enables non-invasive, portable, bedside detection of early vascular changes such as arterial stiffness, measurement of the intima-media thickness, pulse-wave velocity, flow-mediated dilation, or endothelial dysfunction in order to obtain information necessary to determine more closely the relation between vascular status and disease development, so that the evolution of cardiovascular disease can be prevented or at least postponed. Early disease detection enables in-time management, and studies have shown that careful control of vascular risk factors can postpone or even reverse disease progression.