Alzheimer's disease is caused by brain cell death. It is a neurological disorder in which the death of brain cells causes memory loss and cognitive decline. The total size of the brain shrinks in Alzheimer's, nerve cells and connections in the tissue progressively reduced, which cannot be seen or tested in the living brain affected by Alzheimer's disease, post-mortem/autopsy will always show tiny inclusions in the nerve tissues, called as plaques and tangles. Plaques are found between the dying cells in the brain - from the build-up of a protein called beta-amyloid (amyloid plaques). The tangles exist in the brain neurons, from a disintegration of second protein, called tau.