الثلاثاء، 21 أغسطس 2012

Alzheimer's Disease



Alzheimer’s disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills, and eventually even the ability to carry out the simplest tasks. In most people with Alzheimer’s, symptoms first appear after age 60. Estimates vary, but experts suggest that as many as 5.1 million Americans may have Alzheimer’s disease.
Alzheimer’s disease is the most common cause of dementia among older people. Dementia is the loss of cognitive functioning—thinking, remembering, and reasoning—and behavioral abilities, to such an extent that it interferes with a person’s daily life and activities. Dementia ranges in severity from the mildest stage, when it is just beginning to affect a person’s functioning, to the most severe stage, when the person must depend completely on others for basic activities of daily living.
Alzheimer’s disease is named after Dr. Alois Alzheimer. In 1906, Dr. Alzheimer noticed changes in the brain tissue of a woman who had died of an unusual mental illness. Her symptoms included memory loss, language problems, and unpredictable behavior. After she died, he examined her brain and found many abnormal clumps (now called amyloid plaques) and tangled bundles of fibers (now called neurofibrillary tangles). Plaques and tangles in the brain are two of the main features of Alzheimer’s disease. The third is the loss of connections between nerve cells (neurons) in the brain.



symptoms of Alzheimer's disease

Doctors say Alzheimer's disease can sometimes be tricky to diagnose because each patient has unique signs and symptoms. Several of the signs and symptoms present in Alzheimer's disease also exist in other conditions and diseases.

Alzheimer's disease is classified into several stages. Some doctors use a 7-stage framework, while others may use a 4, 5 or 6-stage one.

A common framework includes 1. Pre-Dementia Stage. 2. Mild Alzheimer's Stage. 3. Moderate Alzheimer's Stage. 4. Severe Alzheimer's Stage. The example below is of a 7-stage framework.

The 7 stages of diagnostic framework

Most patients take from 8 to 10 years to progress through all the seven stages. However, some may live for 20 years after neuron changes first occur.

Stage 1 - No impairment

Memory and cognitive abilities seem to be normal. During a medical interview a health care professional identifies no evidence of memory or cognitive problems.

Stage 2 - Minimal Impairment (Very Mild Cognitive Decline)

Could be normal age-related changes, or the earliest signs of Alzheimer's.

Friends, family and health care professionals hardly notice any memory lapses. Approximately 50% of people aged 65 and over start experiencing slight difficulties with recalling the occasional word and concentration. The person may feel there are occasional memory lapses, such as forgetting familiar words or the names, and perhaps where they left their keys, glasses or some other everyday object.

Stage 3 - Early Confusional (Mild Cognitive Decline). Duration - 2 to 7 years.

Early-stage Alzheimer's is sometimes diagnosed at this stage.
  • The patient has slight difficulties which have some impact on certain everyday functions. In many cases the patient will try to conceal the problems.
  • Problems include difficulties with word recall, organization, planning, mislaying things, failing to remember recently learned data which may cause problems at work and at home - family members and close associates become aware.
  • Problem reading a passage and retaining information from it.
  • The ability to learn new things may be affected.
  • Problems with organization.
  • Moodiness, anxiety, and in some cases depression.
Stage 4 - Moderate Cognitive Decline. (Mild or Early Stage Alzheimer's Disease). Duration - about 2 years

With these symptoms diagnosis is easy to confirm.
  • Still identifies familiar people and is aware of self.
  • Reduced memory of personal history.
  • Problems with numbers which impact on family finance - managing bills, checkbooks, etc. Previously doable numerical exercises, such as counting backwards from 88 in lots of 6s become too difficult.
  • Knowledge of recent occasions or current events is decreased.
  • Sequential tasks become more difficult, including driving, cooking, planning dinner for guests, many domestic chores, shopping alone, and reading and then selecting what is in a menu at the restaurant.
  • Withdraws from conversations, social situations, and mentally challenging situations.
  • Denies there is a problem and becomes defensive.
  • Requires help with some of the more complicated aspects of independent living.
Stage 5 - Moderately Severe Cognitive Decline (Moderate or Mid-stage Alzheimer's Disease). Duration - about 18 months
  • Cognitive deterioration is more serious.
  • Cannot survive independently in the community and requires some assistance with day-to-day activities.
  • Cannot remember details about personal history, such as name of where they went to school, telephone numbers, personal address, etc.
  • Confused about what day it is, month, year.
  • Confused about where they are or where things are.
  • Problems with numbers; mathematical abilities get worse.
  • Easy prey for scammers.
  • Require supervision and sometimes help when dressing, including selecting right clothing for the season or occasion.
  • Require help carrying out some daily living tasks.
  • Can still eat and go to the toilet unaided.
  • Unable to recall current information consistently.
  • Usually remember substantial amounts about themselves, such as their name, name of spouse and children.
Stage 6 - Severe Cognitive Decline (Moderately Severe Mid-stage Alzheimer's Disease). Duration - about 2½ years.

Memory continues to deteriorate. There is a considerable change in personality. Require all-round help with daily activities.
  • Virtually totally unaware of present and most recent experiences.
  • Cannot recall personal history very well.
  • Can still usually recall their own name.
  • Know family members are familiar but cannot recall their names.
  • Can communicate pleasure and pain nonverbally.
  • Ability to dress progressively deteriorates. Need help dressing and undressing.
  • Ability to bathe and wash self progressively deteriorates.
  • Fecal and/or urinary incontinence more likely.
  • Need help when going to the toilet - flushing, wiping, disposing of tissues.
  • Disruption of sleep patterns.
  • Wander off and become lost.
  • Suspicious, paranoid, aggressive. May believe caregiver is an impostor, devious, scheming, cunning, dishonest.
  • Repeat words, phrases or repetitively utters sounds.
  • Repetitive/compulsive behavior, such as tearing up tissues or wringing hands.
  • Disturbed, agitated, especially later on in the day.
  • Hallucinations, also more common later on in the day. May hear, smell or see things that are not there.
  • Eventually need care and supervision, but can respond to non-verbal stimuli.
Stage 7 - Very Severe Cognitive Decline (Severe or Late-stage Alzheimer's Disease). Duration - 1 to 2½ years

During the last stage of Alzheimer's disease patients lose the ability to respond to their environment, they cannot speak, and eventually cannot control movement. The duration of this stage may depend on the quality of care the patient receives.
  • Severely limited cognitive ability.
  • Patients lose their ability to recognize speech, but may utter short words or moans to communicate.
  • Usually the ability to walk unaided is lost first, then the ability to sit unaided, plus the ability to smile, and eventually the ability to hold the head up.
  • Body systems start to fail and health deteriorates.
  • Swallowing becomes increasingly more difficult. Chocking when eating/drinking becomes more common.
  • Reflexes become abnormal.
  • Seizures are possible.
  • Muscles grow rigid.
  • Generally bedridden.
  • Spends more time asleep.


causes of Alzheimer's disease

The cause(s) of Alzheimer's disease is (are) not known. The "amyloid cascade hypothesis" is the most widely discussed and researched hypothesis about the cause of Alzheimer's disease. The strongest data supporting the amyloid cascade hypothesis comes from the study of early-onset inherited (genetic) Alzheimer's disease. Mutations associated with Alzheimer's disease have been found in about half of the patients with early-onset disease. In all of these patients, the mutation leads to excess production in the brain of a specific form of a small protein fragment called ABeta (Aβ). Many scientists believe that in the majority of sporadic (for example, non-inherited) cases of Alzheimer's disease (these make up the vast majority of all cases of Alzheimer's disease) there is too little removal of this Aβ protein rather than too much production. In any case, much of the research in finding ways to prevent or slow down Alzheimer's disease has focused on ways to decrease the amount of Aβ in the brain.

 are risk factors for Alzheimer's disease
The biggest risk factor for Alzheimer's disease is increased age. The likelihood of developing Alzheimer's disease doubles every 5.5 years from 65 to 85 years of age. Whereas only 1%-2% of individuals 70 years of age have Alzheimer's disease, in some studies around 40% of individuals 85 years of age have Alzheimer's disease. Nonetheless, at least half of people who live past the 95 years of age do not have Alzheimer's disease.

Common forms of certain genes increase the risk of developing Alzheimer's disease, but do not invariably cause Alzheimer's disease. The best-studied "risk" gene is the one that encodes apolipoprotein E (apoE). The apoE gene has three different forms (alleles) -- apoE2, apoE3, and apoE4. The apoE4 form of the gene has been associated with increased risk of Alzheimer's disease in most (but not all) populations studied. The frequency of the apoE4 version of the gene in the general population varies, but is always less than 30% and frequently 8%-15%. Persons with one copy of the E4 gene usually have about a two to three fold increased risk of developing Alzheimer's disease. Persons with two copies of the E4 gene (usually around 1% of the population) have about a nine-fold increase in risk. Nonetheless, even persons with two copies of the E4 gene don't always get Alzheimer's disease. At least one copy of the E4 gene is found in 40% of patients with sporadic or late-onset Alzheimer's disease.
This means that in majority of patients with Alzheimer's disease, no genetic risk factor has yet been found. Most experts do not recommend that adult children of patients with Alzheimer's disease should have genetic testing for the apoE4 gene since there is no treatment for Alzheimer's disease. When medical treatments that prevent or decrease the risk of developing Alzheimer's disease become available, genetic testing may be recommended for adult children of patients with Alzheimer's disease so that they may be treated.
Many, but not all, studies have found that women have a higher risk for Alzheimer's disease than men. It is certainly true that women live longer than men, but age alone does not seem to explain the increased frequency in women. The apparent increased frequency of Alzheimer's disease in women has led to considerable research about the role of estrogen in Alzheimer's disease. Recent studies suggest that estrogen should not be prescribed to post-menopausal women for the purpose of decreasing the risk of Alzheimer's disease. Nonetheless, the role of estrogen in Alzheimer's disease remains an area of research focus.
Some studies have found that Alzheimer's disease occurs more often among people who suffered significant traumatic head injuries earlier in life, particularly among those with the apoE 4 gene.
In addition, many, but not all studies, have demonstrated that persons with limited formal education - usually less than eight years - are at increased risk for Alzheimer's disease. It is not known whether this reflects a decreased "cognitive reserve" or other factors associated with a lower educational level.


Treating Alzheimer’s Disease

Alzheimer’s disease is complex, and it is unlikely that any one intervention will be found to delay, prevent, or cure it. That’s why current approaches in treatment and research focus on several different aspects, including helping people maintain mental function, managing behavioral symptoms, and slowing or delaying the symptoms of disease.

Maintaining Mental Function

Four medications are approved by the U.S. Food and Drug Administration to treat Alzheimer’s. Donepezil (Aricept®), rivastigmine (Exelon®), and galantamine (Razadyne®) are used to treat mild to moderate Alzheimer’s (donepezil can be used for severe Alzheimer’s as well). Memantine (Namenda®) is used to treat moderate to severe Alzheimer’s. These drugs work by regulating neurotransmitters (the chemicals that transmit messages between neurons). They may help maintain thinking, memory, and speaking skills, and help with certain behavioral problems. However, these drugs don’t change the underlying disease process, are effective for some but not all people, and may help only for a limited time.

Managing Behavioral Symptoms

Common behavioral symptoms of Alzheimer’s include sleeplessness, agitation, wandering, anxiety, anger, and depression. Scientists are learning why these symptoms occur and are studying new treatments—drug and non-drug—to manage them. Treating behavioral symptoms often makes people with Alzheimer’s more comfortable and makes their care easier for caregivers.

Slowing, Delaying, or Preventing Alzheimer’s Disease

Alzheimer’s disease research has developed to a point where scientists can look beyond treating symptoms to think about addressing underlying disease processes. In ongoing clinical trials, scientists are looking at many possible interventions, such as immunization therapy, cognitive training, physical activity, antioxidants, and the effects of cardiovascular and diabetes treatments.

Supporting Families and Caregivers

Caring for a person with Alzheimer’s disease can have high physical, emotional, and financial costs. The demands of day-to-day care, changing family roles, and difficult decisions about placement in a care facility can be hard to handle. Researchers have learned much about Alzheimer’s caregiving, and studies are helping to develop new ways to support caregivers.
Becoming well-informed about the disease is one important long-term strategy. Programs that teach families about the various stages of Alzheimer’s and about flexible and practical strategies for dealing with difficult caregiving situations provide vital help to those who care for people with Alzheimer’s.
Developing good coping skills and a strong support network of family and friends also are important ways that caregivers can help themselves handle the stresses of caring for a loved one with Alzheimer’s disease. For example, staying physically active provides physical and emotional benefits.
Some Alzheimer’s caregivers have found that participating in a support group is a critical lifeline. These support groups allow caregivers to find respite, express concerns, share experiences, get tips, and receive emotional comfort. Many organizations, such as those listed in the “For More Information” section, sponsor in-person and online support groups across the country. There are a growing number of groups for people in the early stage of Alzheimer’s and their families. Support networks can be especially valuable when caregivers face the difficult decision of whether and when to place a loved one in a nursing home or assisted living facility. For more information about at-home caregiving, see Caring for a Person with Alzheimer’s Disease: Your Easy-to-Use Guide from the National Institute on Aging.

Advancing Understanding

Thirty years ago, we knew very little about Alzheimer’s disease. Since then, scientists have made important advances. Research supported by NIA and other organizations has expanded knowledge of brain function in healthy older people, identified ways we might lessen normal age-related declines in mental function, and deepened our understanding of the disease. Many scientists and physicians are now working together to untangle the genetic, biological, and environmental factors that, over many years, ultimately result in Alzheimer’s. This effort is bringing us closer to better managing and, ultimately, preventing this devastating disease.

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