Coloured computed tomography (CT) scan of a coronal section through the brain of a patient with Alzheimer's disease. Alzheimer's is a neurodegenerative disease and a common cause of dementia in the elderly. It causes loss of brain mass, with enlarged central ventricles and deep indentations around the brain's edges. This brain shrinkage leads to memory loss, confusion, personality changes and ultimately death. Its cause is not known and there is no cure.