II Vascular dementia
　　Stroke is the potent risk factor for vascular dementia identified in epidemiologic data. Stroke is caused by a critical alteration of blood flow to a region of the brain. An acute obstruction of an artery results in ischemia i.e., insufficient blood flow to the tissue. The ischemic brain suffers a mismatch between its cellular energy demands and the ability of the vascular system to supply substrate, most importantly oxygen. Subsequently, neurologic malfunctions and neuronal cell death are caused by increased intracellular calcium, excessive extracellular glutamate, free radicals, and inflammation (Figure 2).