02/09/2024
What Is Alzheimer's Disease?
Alzheimer’s is a specific disease of the brain that was identified more than 100 years ago, but research into its causes, risk factors and potential treatments has gained momentum only in the last 30 years. The hallmarks of Alzheimer’s disease are the accumulation of abnormal proteins in the brain: clumps of beta-amyloid (called amyloid plaques) and tangled bundles of tau fibers (called neurofibrillary tangles). Most experts now agree that the accumulation of plaques and tangles in the brain may begin 20 or more years before the symptoms of dementia appear.
Dementia is a term used to designate brain diseases that progressively and permanently undermine cognitive function and behavior to the point where the individual is no longer able to carry out customary activities at work or at home. Alzheimer’s disease is one of many dementias. It happens to be the most common dementia seen in old age. It is an irreversible, progressive brain disease. It slowly destroys brain function and leads to dementia. It is characterized by cognitive decline (e.g., memory loss, confusion and poor reasoning); behavioral and psychiatric disorders (e.g., depression, delusions, agitation); and declines in functional status (e.g., ability to perform activities of daily living and self-care).
What Are the Symptoms?
The first symptom of Alzheimer’s disease is often memory impairment. As the disease progresses, memory continues to decline and other functions, like language skills and decision-making, become more difficult. Personality and behavior changes also may occur. A person with the disease may no longer recognize family and friends.
Eventually, the person who survives with Alzheimer’s disease is completely reliant on others for assistance with the most basic activities of daily living, such as eating. In more than 90 percent of people with Alzheimer’s disease, symptoms do not appear until after age 60 and the incidence of the disease increases with age.
However, there are other types of dementia caused by other diseases and conditions in the brain, such as frontotemporal, Lewy Body and vascular dementias. Some of these, such as frontotemporal, start at a much younger age when a person is in their 50s and early 60s, and can impair language or behavior, while leaving memory intact. Distinguishing between Alzheimer’s disease and other dementias, in terms of clinical presentation and diagnosis, may be challenging and may require extensive testing in specialized centers. Researchers now recognize that many of these diseases and conditions can co-occur in the brain and work together to influence the onset of dementia. The term “Alzheimer’s disease and related dementias” often are used to refer to Alzheimer’s disease and related neurodegenerative disorders.
What May Prevent or Delay the Onset of Alzheimer's Disease?
Many current studies are investigating the benefits of exercise, diet and other lifestyle modification that may prevent or delay the onset of Alzheimer’s disease. The causes of Alzheimer’s disease are not completely understood, but researchers believe they include a combination of genetic, environmental and lifestyle factors. The importance of any one of these factors in increasing or decreasing the risk of developing Alzheimer’s disease may differ from person-to-person. In rare cases, known as early or younger-onset Alzheimer’s disease, people develop symptoms in their 30s, 40s or 50s.
