Alzheimer's disease (AD), which was first described in 1906, is the most common form of dementia among the elderly. Dementias are related to brain damage caused by certain diseases, including AD, a pathology that seriously affects a person's ability to carry out daily activities and eventually leads to death.
The disease first affects the parts of the brain that control memory and language, and the related problem of mild cognitive impairment causes more memory problems than normal in people of the same age than those who suffer AD. Over time, AD symptoms get worse. People may not recognize their closest relatives, they may have difficulty speaking, reading, or writing, and they may forget how to perform basic daily life tasks. Behaviour and mood changes are often associated.
The causes of AD are unknown. During the evolution of the disease structures build up in the brain and form “plaques” of beta-amyloid protein and “tangles” of tau protein, which at first interrupt connections between neurons and lead eventually to cell death. A related process which additionally worsens the functioning of the neurological connections is the loss or shortage of neurotransmitters in the brain. Although both the protein structure formations and losses of neurotransmitters are characteristics of AD, it is unclear to what extent they cause it or are a by-product of the pathology.
Alzheimer's disease is not a normal part of growing older but age is its best-known risk factor: The older one gets, the greater the chances of developing the disease. AD often begins after the age of 60 and the risk increases as the person ages. The risk may be higher if there are people in the family who had the disease because genetic factors could also play a part.
Some studies suggest that AD’s rate is higher in certain ethnic groups. Also, people with certain medical history are at increased risk of developing the disease, including people with Down syndrome and other intellectual and developmental disorders, and people who have suffered repeated concussions.
No treatment can stop the disease. However, some drugs may help prevent the symptoms from getting worse for a limited time.
Now, the experience of each person with Alzheimer's disease or dementia is different. In addition, loss of memory or confusion may be caused by other problems. Sometimes these same symptoms are the result of an easy-to-treat problem, which is why it is so important to get the proper diagnosis so that the treatment can address the correct problem.
Scientists continue to explore factors that could increase chances of having Alzheimer's and, equally importantly, what could protect people from developing the disease.