WHAT IS ALZHEIMER'S DISEASE?
Alzheimer's disease (AD) is an age-related, non-reversible brain disorder that develops over a period of years.
Initially, people experience memory loss and confusion, which may be mistaken for the kinds of member changes that
are sometimes associated with normal aging. However, the symptoms of AD gradually lead to behavior and personality
changes, decline in cognitive abilities such as decision-making and language skills, and problems recognizing family
and friends. AD ultimately leads to severe loss of mental function. These are related to the worsening breakdown
of the connections between certain neurons in the brain and their eventual death. AD is one of a group of disorders
called dementias that are characterized by cognitive and behavioral problems. It is the most common cause of dementia
among people age 65 and older.
These are three major hallmarks in the brain that are associated with the disease process of AD.
- Amyloid Plaques, which are made of fragments of a protein called beta-amyloid
peptide mixed with a collection of additional proteins, remnants of neurons, and bits and pieces of other nerved
- Neurofibrillary tangles (NFTS), found inside neurons, are abnormal collections
of a protein called tau. Normal tau is required for healthy neurons. However, in AD, tau clumps together. As a
result, neurons fail to function normally and eventually die.
- Loss of connections between neurons responsible for memory and learning. Neurons
can't survive when they lose their connections to other neurons. As neurons die thought out the brain, the affected
regions begin to atrophy, or shrink. By the final stage of AD, damage is widespread and brain tissue has shrunk
Is there any treatment?
Currently there are no medicines that can slow the progression of AD.
However, four FDA-approved medications are used to treat AD symptoms. These drug help individuals carry out the
activities of daily living by maintaining thinking, memory or speaking skills. They can also help with some of
the behavioral and personality changes associated with AD. However, they will not stop or reverse AD and appear
to help individuals for only a few months to a few years. Donepezil (Aricept), rivastigmine (Exelon), and galantamine
(Reminyl (and prescribed to treat mild to moderate AD symptoms. Donepezil was recently approved to treat severe
AD as well. The newest AD medication is memantine (Namenda), which is prescribed to treat moderate to severe AD
What is the prognosis?
In a very few families, people develop AD in their 30s, 40s, and 50s.
This is known as "early onset" AD. These individuals have a mutation in one of three different inherited
genes that causes the disease to begin at an earlier age. More than 90 percent of AD develops in people older than
65. This form of AD is called "late-onset" AD, and its development and pattern of damage in the brain
is similar to that of early-onset AD. The course of this disease varies from person to person, as does the rate
of decline. In most people with AD, symptoms first appear after age 65.
We don't yet completely understand the causes of late-onset AD, but they probably include genetic, environmental,
and lifestyle, factors. Although the risk of developing AD increases with age, AD and dementia symptoms are not
a part of normal aging. There are also some forms of dementia that aren't related to brain disease such as AD,
but are caused by systemic abnormalities such as metabolic syndrome, in which the combination of high blood pressure,
high cholesterol, and diabetes causes confusion and memory loss.
What research is being done?
The National Institute of Neurological Disorders and Stroke (NINDS) supports
basic and translational research related to AD through grants to major medical institutions across the country.
Current studies are investigating how the difference of beta amlyoid plaques damages neurons, and how abnormalities
in tau proteins create the characteristic neurofibrillary tangles of AD. Other research is exploring the impact
of risk factors associated with the development of AD, such as pre-existing problems with blood flow in the blood
vessels of the brain. Most importantly, the NINDS supports a number of studies that are developing and testing
new and novel therapies that can relive the symptoms of AD and potentially lead to a cure.
*****excerpt taken from the website of National Institute of Neurological
Disorders and Stroke; National Institutes of Health