Alzheimer's disease attacks the brain, causing problems with memory, thinking and behavior. Symptoms usually develop slowly and get worse over time, becoming severe enough to interfere with daily tasks. Alzheimer's is a form of dementia and accounts for 60 to 80 percent of dementia cases.
What are the symptoms?Memory loss is one of the earliest symptoms, along with a gradual decline of other intellectual and thinking abilities, called cognitive functions, and changes in personality or behavior.
Symptoms of Alzheimer's disease include memory loss, language deterioration, impaired ability to mentally manipulate visual information, poor judgment, confusion, restlessness and mood swings. Eventually Alzheimer's destroys cognition, personality, and the ability to function. The early symptoms, which include forgetfulness and loss of concentration, are often missed because they resemble natural signs of aging, rather than warning signs that indicate something more serious is at work.
Who gets it?
It usually begins after age 65 and the risk increases with age. About one-third of people age 85 and older have the disease. AD is a progressive condition, but its course can vary widely. It damages the brain, which in turn can result in complications that lead to death, such as trouble swallowing, increased risk of choking, aspiration and increased susceptibility to infection. The time course of the disease varies by individual, ranging from five to 20 years.
What are the stages?
Dementia symptoms gradually increase in severity over a number of years. The disease advances in stages, progressing from mild forgetfulness and cognitive impairment to widespread loss of mental abilities. Generally, as the disease goes on, symptoms are more easily noticed and become more serious. Forgetfulness escalates and begins interfering with daily life and activities.
The early stages are almost unnoticeable. A person can function independently, drive and participate in social activities with little to no difficulty. Within a few years, friends and family will most likely begin to notice the person has a hard time remembering names or uses the wrong words when speaking.
The moderate stages usually last the longest period of time. Your loved one may become easily frustrated or angered and not want to participate in normal daily activities such as bathing or getting dressed. Those in the middle stages may forget how to do simple tasks like brushing their teeth or combing their hair. They also begin to have problems speaking, comprehending others when they are speaking, and reading or writing. Changes in sleep patterns become noticeable and disruptive as well. Actual personality changes may take place.
In advanced Alzheimer's, people become dependent on others for every aspect of their care, including basic activities of daily living. Many patients lose the ability to respond to their environment. Memory and cognitive skills will almost disappear as they lose awareness of their surroundings and recent experiences. Communicating will become nearly impossible, and the risk of infection increases dramatically.
Later on, people with AD may become anxious or aggressive, or wander away from home. Eventually, patients require total care and supervision, often around the clock for their safety.
How does it affect the brain?
The "clumps" that develop in brain tissue are called amyloid plaques and the tangles are called neurofibrillary tangles. These plaques and tangles in the brain are the prime suspects in damaging and killing nerve cells, and are considered telltale signs of this disease.
Microscopic changes in the brain begin long before the first signs of memory loss, though. Cellular degeneration occurs, especially in pathways and areas of the brain that are vital to memory and other mental abilities. There also are lower levels of some of the chemicals in the brain that carry complex messages back and forth between nerve cells. The disease disrupts normal thinking and memory by blocking these messages.
How is it diagnosed?
AD often goes unrecognized or undiagnosed in the early stages because the first symptoms are often viewed as normal effects of aging. For proper diagnosis, doctors use a series of tests and tools to evaluate thinking, behavior and physical function because there is no single scale that can definitively diagnose the disease.
Diagnostic tests may include the Clock Drawing test, the Mini-Mental Stage Examination (MMSE) and the Functional Assessment Staging test (FAST). In addition to these tests, the doctor may also conduct a medical and family health history, a routine physical exam, an exam that tests physical sensation controlled by the central nervous system, a brain scan, a neuropsychological evaluation, and interviews with family members and friends.
However, the only definite way to diagnose this disease is to find out whether there are plaques and tangles in the person's brain tissue. To inspect brain tissue, though, doctors usually must wait until they do an autopsy. Therefore, doctors can only make a diagnosis of "possible" or "probable" Alzheimer's disease while the person is still alive. At specialized medical centers, doctors are able to correctly diagnose the disease up to 90 percent of the time.