The brains of persons with Alzheimer’s disease have structures known as plaques and tangles that are not present in the brains of people without Alzheimer’s disease. Dementia researchers believe that these plaques and tangles destroy neurons, which are the basic nerve cells in the brain. The destruction of neurons in different lobes of the brain is responsible for the cognitive changes seen in persons with Alzheimer’s disease. As neurons are destroyed, the size of the brain shrinks.
Alzheimer’s disease is not the only type of dementia. Some conditions cause progressive deterioration in the person’s cognitive ability. These conditions include: