Alzheimer’s disease is a progressive brain disorder that gradually destroys an individual’s memory, behaviour, personality, and ability to carry out normal daily activities. Two prominent features of AD-related changes in the brain are accumulation of beta-amyloid plaques and tau neurofibrillary tangles. It is believed that the formation of plaques and tangles is harmful, damaging the brain, and is related to the severe cognitive decline in AD.
There are other diseases that cause dementia. These have different types of changes in the brain and may be caused by different factors but have symptoms similar to AD. It is for this reason an autopsy must be performed.
Lewy body disease, the second most frequent cause of neurodegenerative dementia also affects memory, language, and ability to reason. It is marked by an accumulation of abnormal protein called alpha-synuclein inside neurons. Pick's disease, or frontotemporal dementia, is a less common degenerative brain illness that causes dementia, personality changes and language difficulties and is marked by Pick Bodies. Vascular dementia (VaD) results from reduced blood flow to the brain’s nerve cells. VaD often occurs with AD and results in a “mixed dementia".
Despite many advances in neurodegenerative disease research, the causes are not known. There is a great deal that must be learned so that we may one day cure these debilitating diseases.