Alzheimer´s disease is a brain disorder named for German physician Alois Alzheimer, who first described it in 1906. Scientists have learned a great deal about Alzheimer’s disease in the century since Dr. Alzheimer first drew attention to it; but we still are not 100 % sure of the ethology of the disease.
Today we know that Alzheimer’s:
- Is a progressive and fatal brain disease. Alzheimer's destroys brain cells, causing problems with memory, thinking and behaviour severe enough to affect work, lifelong hobbies or social life. Alzheimer’s gets worse over time, and it is fatal. Today it is the seventh-leading cause of death in the United States.
- Is the most common form of dementia, a general term for the loss of memory and other intellectual abilities serious enough to interfere with daily life. Alzheimer’s disease accounts for 50 to 70 percent of dementia cases. Other types of dementia include vascular dementia, mixed dementia, dementia with Lewy bodies and frontotemporal dementia.
- Has no current cure. But treatments for symptoms, combined with the right services and support, can make life better for the millions living with Alzheimer’s. There is an accelerating worldwide effort under way to find better ways to treat the disease, delay its onset, or prevent it from developing.
Just like the rest of our bodies, our brains change as we age. However, serious memory loss, confusion and other major changes in the way our minds work are not a normal part of aging. They may be a sign that brain cells are failing.
The brain has 100 billion nerve cells (neurons). Each nerve cell communicates with many others to form networks. Nerve cell networks have special jobs. Some are involved in thinking, learning and remembering. Others help us see, hear and smell. Still others tell our muscles when to move. In Alzheimer’s disease, as in other types of dementia, increasing numbers of brain cells deteriorate and die.
Two abnormal structures called plaques and tangles are prime suspects in damaging and killing nerve cells. Plaques and tangles were among the abnormalities that Dr. Alois Alzheimer saw in the brain of his patient Auguste D., although he called them different names.
- Plaques build up between nerve cells. They contain deposits of a protein fragment called beta-amyloid. Tangles are twisted fibres of another protein called tau.
- Tangles form inside dying cells. Though most people develop some plaques and tangles as they age, those with Alzheimer’s tend to develop far more. The plaques and tangles tend to form in a predictable pattern, beginning in areas important in learning and memory and then spreading to other regions.
Scientists are not absolutely sure what role plaques and tangles play in Alzheimer’s disease. Most experts believe they somehow block communication among nerve cells and disrupt activities that cells need to survive.