Last Updated on Thursday, 18 March 2010 09:55
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Alzheimer's Disease Overview
Alzheimer's disease is a progressive, degenerative disease of the brain which causes thinking and memory to become seriously impaired.1 It is the most common form of dementia and is named after the German physician Alois Alzheimer who first identified the condition in 1906.2 Alois Alzheimer described the appearance of 'tangles' and 'plaques' which have since been found to be caused by a build-up of proteins in the brain and play a part in its deterioration.2
Alzheimer's disease gradually affects the ability of the brain to function properly, causing the loss of intellectual and social abilities severe enough to interfere with daily functioning.3 This happens because nerve cells, in certain areas of the brain which control a person's mental abilities, start to deteriorate and die. The reason this happens is not fully known, but may be due to the build up of plaques and tangles in the brain.
Alzheimer's disease proceeds in stages over months or years and gradually destroys memory, reason, judgment, language, and eventually the ability to carry out even simple tasks.4 People with Alzheimer's disease experience difficulties severe enough to have an impact on their work, social activities, and family life.5 While there is currently no cure for Alzheimer's disease, there are treatments to help temporarily slow the progression of the symptoms of the disease.6
What causes Alzheimer's disease?7
Scientists don't yet fully understand what causes Alzheimer's disease, but it is clear that it develops because of a complex series of events that take place in the brain over a long period of time. It is likely that the causes include genetic, environmental, and lifestyle factors. Because people differ in their genetic make-up and lifestyle, the importance of these factors for preventing or delaying Alzheimer's disease differs from person to person.7
Genetics play a role in some people with Alzheimer's disease. A rare type of Alzheimer's disease, called early-onset Alzheimer's disease, affects people aged 30 to 60. Some cases of early-onset Alzheimer's disease, called familial Alzheimer's disease, are inherited. Familial Alzheimer's disease is caused by mutations (permanent changes) in three specific genes. Offspring in the same generation have a 50% chance of developing familial Alzheimer's disease if one of their parents had it.7
Most cases of Alzheimer's disease are late-onset Alzheimer's disease, which develops after the age of 60. Although a specific gene has not been identified as the cause of late-onset Alzheimer's disease, genetic factors do appear to increase a person's risk of developing the disease. This increased risk is related to the apoliprotein E (APOE) gene. The APOE gene has several forms. One of them, APOE ÃŽÂµ4, occurs in about 40 percent of all people who develop late-onset Alzheimer's disease. However, at least one-third of people with Alzheimer's disease do not have this form of the gene.7
Four to seven other Alzheimer's disease risk-factor genes may exist as well. One of them, SORL1, was discovered in 2007. Large-scale genetic research studies are looking for other risk-factor genes.7
Research suggests that certain lifestyle factors, such as a nutritious diet, exercise, social engagement, and mentally stimulating pursuits, might help to reduce the risk of cognitive decline and Alzheimer's disease. Scientists are investigating associations between cognitive decline and heart disease, high blood pressure, diabetes, and obesity. Understanding these relationships and testing them in clinical trials will help us understand whether reducing risk factors for these diseases may help with Alzheimer's disease as well.7
How many people suffer from Alzheimer's disease?
In Europe, it is estimated that one in every 20 people over the age of 65 has Alzheimer's disease and the numbers are predicted to double in Western Europe and treble in Eastern Europe by 2040.8 However, a report published in the UK in 2007 estimated that among those who suffer from dementia, only one-third to one-half receive a formal diagnosis.9 Indeed, a recent online survey amongst Americans aged 55 years and over, found that one-third of people surveyed knew someone whom they suspect might have Alzheimer's disease. Yet of those people, only 38% encouraged this person to talk to a doctor about it.10
What are the symptoms of Alzheimer's disease?
Although symptoms of Alzheimer's disease can vary widely, the first problem many people notice is forgetfulness severe enough to affect their ability to function at home or at work, or to enjoy lifelong hobbies.11
Other symptoms include confusion, getting lost in familiar places, misplacing things and problems with speaking and writing. The list below 12 details some of the common signs and symptoms of Alzheimer's disease:
Abstract Thinking -- Balancing a chequebook may be hard when the task is more complicated than usual. Someone with Alzheimer's disease, however, might forget what the numbers are and what needs to be done with them.
Disorientation -- It's normal to forget the day of the week or where you're going, but people with Alzheimer's disease can become lost on the street where they live, forget where they are and how they got there, and not know how to get back home.
Initiative -- People often tire of housework, business activities or social obligations at times. However, a person with Alzheimer's disease may become excessively passive, sitting in front of the television for hours, sleeping more than usual or not doing usual activities.
Judgment -- No one has perfect judgment all the time, but those with Alzheimer's disease may dress without regard to the weather, for instance wearing several shirts on a warm day. Individuals with dementia often show poor judgment about money, giving away large amounts to telemarketers or paying for repairs or products they don't need.
Language -- All of us have trouble finding the right word from time to time, but people with Alzheimer's disease often forget simple words or substitute unusual words, making their speech or writing hard to understand. If a person with Alzheimer's disease is unable to find a toothbrush, for example, they may ask for "that thing for my mouth".
Misplacing Items -- Anyone can temporarily misplace a wallet or key. A person with Alzheimer's disease may put things in unusual places: an iron in the freezer or a wristwatch in the sugar bowl.
Mood Changes -- Everyone can become sad or moody from time to time. However, someone with Alzheimer's disease can show rapid mood swings (from calm to tears to anger) for no apparent reason.
Personality -- Personalities ordinarily change somewhat with age but a person with Alzheimer's disease may have a severe personality change, becoming extremely confused, suspicious, fearful or dependent on a family member.
How is Alzheimer's disease diagnosed?
A diagnosis of Alzheimer's disease can often be difficult particularly in the early stages. It is important to distinguish Alzheimer's disease from other forms of dementia and to rule out other causes of the symptoms which require specific treatment.13 There is no single test to determine whether someone definitely has Alzheimer's disease. However, doctors can determine fairly accurately whether a person may have Alzheimer's disease by conducting several screening tests, which help eliminate other conditions, and by conducting a careful examination of a person's physical and mental state. The main tests used to diagnose Alzheimer's disease look at memory, language, perceptual skills, attention, orientation, problem-solving and functional abilities.14 A healthcare professional can diagnose the cause of these problems and experts estimate that a skilled physician can diagnose Alzheimer's disease with more than 90% accuracy.15
The doctors may decide on further tests such as brain scans which will locate any damaged areas of the brain. The results of these tests can provide further evidence to support diagnosis.
How is Alzheimer's disease treated?
Currently, there is no known cure or prevention for Alzheimer's disease however there are several medications available to treat its symptoms.6 A doctor will need to assess the most appropriate treatment for each individual and monitor the patient carefully over time to assess if modifications to treatment are needed as the symptoms of Alzheimer's disease progress. A doctor may also recommend lifestyle modifications to help manage the disease.
It is vital that Alzheimer's disease is diagnosed as early as possible. Having an early diagnosis, starting treatment and putting lifestyle modifications in place in the early stages of Alzheimer's disease can help individuals prepare for the future by managing their disease early on.16
Visit the Memory Problems? website www.aboutmemoryproblems.com for further information about Alzheimer's disease.
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 Alzheimer's Association. What is Alzheimer's? Available at URL: http://www.alz.org/alzheimers_disease_what_is_alzheimers.asp. Last updated 18 February 2010. Last accessed February 2010.
 Mayo Clinic. Alzheimer's disease definition. Available at URL: http://www.mayoclinic.com/health/alzheimers-disease/DS00161. Last updated 17 January 2009. Last accessed February 2010.
 Agency for Healthcare Research and Quality. Understanding Your Body: What Is Alzheimer's Disease? Agency for Healthcare Research and Quality website. US Department of Health and Human Services. Available at URL: http://www.ahrq.gov/consumer/bodysys/edbody9.htm. Last accessed February 2010.
 Alzheimer's Association. 10 Signs of Alzheimer's. Available at URL: http://www.alz.org/alzheimers_disease_10_signs_of_alzheimers.asp. Last updated 17 February 2010. Last accessed February 2010.
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 Alzheimer's Disease Screening Discussion Group. Alzheimer's Disease 2008: Current Attitudes and Perceptions Survey. You Can Be the One website (sponsored by Eisai Inc and Pfizer Inc). Available at URL: http://www.seethesigns.com/pdf/ADSDG_Survey.pdf. Last accessed February 2010.
 Alzheimer's Association. Alzheimer's Disease Facts and Figures. act website. Available at URL: http://www.actionalz.org/facts_figures.asp. Last accessed February 2010.
 University of California, San Francisco. Alzheimer's Disease: Signs and Symptoms. University of California San Francisco Medical Center website. Available at URL: http://www.ucsfhealth.org/adult/medical_services/memory/alz/conditions/alzheimers/. Last updated February 2008. Last accessed February 2010.
 Alzheimer's Society. Diagnosis and Assessment. Available at URL: http://www.alzheimers.org.uk/factsheet/426. Last updated July 2008. Last accessed February 2010.
 Rao SM, Swanson SJ. Neuropsychological Assessment. In: Schiffer RB, Rao SM, Fogel BS, ed. Neuropsychiatry. Philadelphia, Pennsylvania: Lippincott Williams and Wilkins; 2nd Edition, 2005: Chapter 2: Neuropsychological Assessment. 20-42
 Alzheimer's Association. Steps to Diagnosis. Alzheimer's Association website. Available at URL: http://www.alz.org/alzheimers_disease_steps_to_diagnosis.asp. Last updated July 2009. Last accessed February 2010.
 Doraiswamy PM, Steffens DC, Pitchumoni S, Tabrizi S. Early Recognition of Alzheimer's disease: what is consensual? What is controversial? What is practical? J Clin Psychiatry. 1998;59(suppl. 13):6-18.