Subcortical vascular dementia, also called Binswanger's disease, is caused by widespread, microscopic areas of damage to the brain resulting from the thickening and narrowing (atherosclerosis) of arteries that supply blood to the subcortical areas of the brain. Atherosclerosis (commonly known as "hardening of the arteries") is a systemic process that affects blood vessels throughout the body. It begins late in the fourth decade of life and increases in severity with age. As the arteries become more and more narrowed, the blood supplied by those arteries decreases and brain tissue dies.
Brain imaging shows the brain lesions typical of the disease and is essential for an accurate diagnosis. The most characteristic feature of vascular dementia is psychomotor slowness - an increase in the length of time it takes, for example, for the fingers to turn the thought of a letter into the shape of a letter on a piece of paper. Other symptoms include forgetfulness (but not as severe as the forgetfulness of Alzheimer's disease), changes in speech, unsteady gait, clumsiness or frequent falls, changes in personality or mood or urinary symptoms.
Controlling medical risk factors including hypertension, diabetes and elevated cholesterol - along with consuming a healthy diet, exercising, and not drinking too much alcohol or smoking - can slow the progression of vascular dementia. Vascular dementia often coexists with Alzheimer's disease.
A small group of rare disorders cause rapidly progressing dementias, in which people get worse week by week rather than over a period of years. Prion diseases, such as Creutzfeldt-Jakob disease, are the most common cause of rapidly progressing dementias. Prions are misfolded proteins that kill cells and produce the symptoms.