It is clinical condition which occurs due to obstacles in the supply of blood to the brain which results in to minor stroke. It is second common form of dementia after Alzheimer's disease (AD) in aged person. Risk factor of this disease is age, hypertension, smoking, hypercholesterolemia, diabetes mellitus and cardiovascular diseases etc. It can be managed by preventing cerebrovascular lesions and by giving medication such as cholinesterase inhibitors.