[h=1]Brain may 'compensate' for Alzheimer's damage[/h] By Smitha Mundasad Health reporter, BBC News
The brains of Alzheimer's patients often have tangles of proteins called amyloid plaques
The human brain may be able to compensate for some of the early changes seen in Alzheimer's disease, research in Nature Neuroscience shows.
The study suggests some people recruit extra nerve power to help maintain their ability to think. Scientists hope the findings could shed light on why only some people with early signs of the condition go on to develop severe memory decline. But experts warn much more research is needed to understand these processes. [h=2]Start Quote[/h]
I think it is very possible that people who spend a lifetime involved in cognitively stimulating activity have brains that are better able to adapt to potential damage
Dr William Jagust University of California
'Protein tangles' The study, led by researchers at the University of California, involved 71 adults with no signs of mental decline.
Brain scans showed 16 of the older subjects had amyloid deposits - tangles of protein that are considered a hallmark of Alzheimer's disease.
All participants were asked to memorise a series of pictures in detail while scanners were used to track their brain activity.
They were then asked to recall the gist and later the detail of all the pictures they had seen. Both groups performed equally well but those with tangles of amyloid in their brains showed more brain activity when remembering the images in detail.
Scientists say this suggests their brains have an ability to adapt to and compensate for any early damage caused by the protein.
Brain stimulation Dr Laura Phipps, at the charity Alzheimer's Research UK, said: "This small study suggests that our brains may have ways of resisting early damage from these Alzheimer's proteins but more research is needed to know how to interpret these results. She added: "Longer term studies are needed to confirm whether the extra brain activity seen in this research is a sign of the brain compensating for early damage, and if so, how long the brain might be able to fight this damage."
Scientists say they need to understand why some people with an accumulation of this protein are better at using different parts of their brain than others. Dr William Jagust, a researcher on the study, said: "I think it is very possible that people who spend a lifetime involved in cognitively stimulating activity have brains that are better able to adapt to potential damage."
Dementia is described as a "global disaster waiting to happen" and the biggest health and care problem of a generation. Someone is diagnosed with the disease every four seconds and cases are expected to soar from 44 million now to 135 million by 2050.
The disease already costs the world 370bn ($604bn) each year. Ministers from the G8 major economies have pledged to tackle this devastating disease. So what are the priorities?
Diagnose dementia early
Loss of tissue in a demented brain compared with a healthy one
Early diagnosis will be key to tackling dementia. On the day your doctor tells you that you have dementia you might think that's the early stages of the disease, but it's not.
What is dementia?
It's an umbrella term that describes around 100 diseases in which brain cells die on a huge scale.
All damage memory, language, mental agility, understanding and judgement.
Alzheimer's disease is the most common form, affecting 62% of those living with dementia.
It gets worse with time and eventually people are left completely dependent on carers.
It takes 10 to 15 years of brain cells dying before memory problems become noticeable and memory tests lead to a diagnosis. By this stage a fifth of the core memory centres of the brain will be dead. It's why doctors think drug trials have failed, they're simply trying to treat the disease way too late. Prof Nick Fox, from the National Hospital for Neurology and Neurosurgery in London, says focusing on earlier treatment is "absolutely critical to research".
Developments have been made. It is now possible to see one of the damaged proteins closely tied to Alzheimer's disease in brain scans, but the challenge is to use these tools to predict the development of dementia. "There have been huge advances in brain imaging, it's a new era and it is very exciting," said Prof Fox. Other methods, such as finding chemicals in the blood which might predict the onset of dementia, are being investigated as well.
Dementia is also not one disease, but many. Alzheimer's disease, vascular dementia and dementia with Lewy bodies all have similar symptoms, but may need different treatments. Scientists will need to come up with techniques which can readily distinguish between different forms of dementia.
Stop brain cells dying
There is no drug which can halt or even slow the progression of any form of dementia. A lot of hope was placed on two potential Alzheimer's drugs - solanezumab and bapineuzumab - but they failed in trials which showed no benefits for cognition.
However, there were hints that solanezumab may work in people with the earliest stages of the disease. A new trial has started looking at patients with mild dementia. Dr Eric Karran, director of research at Alzheimer's Research UK, said that if it was shown to work then the drug may be used in a similar way to statins for heart problems.
"I think the pathway now is if solanezumab is shown to work in mild Alzheimer's disease then the pathway would be to give it earlier and earlier and earlier... and you could have confidence you will see an effect." A cure is obviously the dream, but just slowing the pace of the disease would deliver massive rewards. Delaying dementia by five years could halve the number of people living with the disease.
Develop drugs to treat the symptoms
Memantine was the last new dementia drug
There are dementia drugs, which help people to live with the condition, but there are not enough. Medication can boost the chemical signalling between surviving brain cells. But the last new medicine, memantine, was approved by the US in 2003. Since then there's been nothing.
Dr Ronald Petersen, the director of the Alzheimer's Disease Research Centre at the Mayo Clinic, US, told the BBC: "That's horrific when you think about the billions invested in the disease. "There are 44 million people with Alzheimer's and we have to treat them as well [as find a cure]. "We need to develop drugs both to treat the symptoms and slow the progression of the disease, as we do after a heart attack."
Find ways to reduce the risk
Want to massively cut the risk of lung cancer? Don't smoke. Want to avoid a heart attack? Then exercise and have a healthy diet. Don't want dementia? Then the answer is less certain.
Age is the biggest risk factor. In the UK, one in three people over the age of 95 has dementia, but there's not much people can do about that. Many of the familiar messages - exercise and eat healthily - have been linked to preventing or delaying the onset of dementia. But the full picture of how family history, lifestyle choices and the environment combine to result in dementia is still unclear. Prof Peter Passmore, from the British Geriatrics Society and Queen's University Belfast, says the best advice so far is: "To do what's healthy for the heart to reduce blood vessel damage to the brain. "So avoid obesity, don't smoke, regular exercise, control blood pressure, sugar and cholesterol. "These are not likely to do harm and may well do good."
Work out the best care
Dementia has huge costs for society, but medical bills account for only a small fraction of the overall bill. The real cost is in time in care homes and the lost income of families quitting work to care for relatives. Research will also need to focus on the best ways to care for patients with dementia and to keep them independent for as long as possible.
Studies have already shown that antipsychotic prescriptions can be halved with the correct training for staff. Dr Doug Brown, from the Alzheimer's Society, said: "If there is any low hanging fruit in dementia it is the care-based research. "There's a lot we can do about researching the care and support we provide people with now so they can live as well as possible." http://www.bbc.com/news/health-25263341
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.
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[TD] [h=3] Looking for information about Alzheimer’s disease?[/h]
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[/TABLE] 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.
[h=2] Changes in the Brain in Alzheimer’s Disease[/h] [TABLE="class: right, width: 129, align: right"]
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[TD="align: center"]As Alzheimer's disease progresses, neurofibrillary tangles (shown in blue) and amyloid plaques spread throughout the brain.[/TD]
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[/TABLE] Although we still don’t know how the Alzheimer’s disease process begins, it seems likely that damage to the brain starts a decade or more before problems become evident. During the preclinical stage of Alzheimer’s disease, people are free of symptoms but toxic changes are taking place in the brain. Abnormal deposits of proteins form amyloid plaques and tau tangles throughout the brain, and once-healthy neurons begin to work less efficiently. Over time, neurons lose their ability to function and communicate with each other, and eventually they die. Before long, the damage spreads to a nearby structure in the brain called the hippocampus, which is essential in forming memories. As more neurons die, affected brain regions begin to shrink. By the final stage of Alzheimer’s, damage is widespread, and brain tissue has shrunk significantly.
[h=3] Very Early Signs and Symptoms[/h] Memory problems are typically one of the first warning signs of cognitive loss, possibly due to the development of Alzheimer’s disease. Some people with memory problems have a condition called amnestic mild cognitive impairment (MCI). People with this condition have more memory problems than normal for people their age, but their symptoms are not as severe as those seen in people with Alzheimer’s disease. Other recent studies have found links between some movement difficulties and MCI. Researchers also have seen links between MCI and some problems with the sense of smell. The ability of people with MCI to perform normal daily activities is not significantly impaired. However, more older people with MCI, compared with those without MCI, go on to develop Alzheimer’s. A decline in other aspects of cognition, such as word-finding, vision/spatial issues, and impaired reasoning or judgment, may also signal the very early stages of Alzheimer’s disease. Scientists are looking to see whether brain imaging and biomarker studies, for example, of people with MCI and those with a family history of Alzheimer’s, can detect early changes in the brain like those seen in Alzheimer’s. Initial studies indicate that early detection using biomarkers and imaging may be possible, but findings will need to be confirmed by other studies before these techniques can be used to help with diagnosis in everyday medical practice. These and other studies offer hope that someday we may have tools that could help detect Alzheimer’s early, track the course of the disease, and monitor response to treatments.
[h=3] Mild Alzheimer’s Disease[/h] As Alzheimer’s disease progresses, memory loss worsens, and changes in other cognitive abilities are evident. Problems can include, for example, getting lost, trouble handling money and paying bills (PDF, 159K), repeating questions, taking longer to complete normal daily tasks, using poor judgment, and having some mood and personality changes. People often are diagnosed in this stage.
[h=3] Moderate Alzheimer’s Disease[/h] In this stage, damage occurs in areas of the brain that control language, reasoning, sensory processing, and conscious thought. Memory loss and confusion grow worse, and people begin to have problems recognizing family and friends. They may be unable to learn new things, carry out tasks that involve multiple steps (such as getting dressed), or cope with new situations. They may have hallucinations, delusions, and paranoia, and may behave impulsively.
[h=3] Severe Alzheimer’s Disease[/h] By the final stage, plaques and tangles have spread throughout the brain, and brain tissue has shrunk significantly. People with severe Alzheimer’s cannot communicate and are completely dependent on others for their care. Near the end, the person may be in bed most or all of the time as the body shuts down.
[h=2] What Causes Alzheimer’s[/h] Scientists don’t yet fully understand what causes Alzheimer’s disease, but it has become increasingly 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 some mix of genetic, environmental, and lifestyle factors. Because people differ in their genetic make-up and lifestyle, the importance of any one of these factors in increasing or decreasing the risk of developing Alzheimer’s may differ from person to person.
[h=3] The Basics of Alzheimer’s[/h] Scientists are conducting studies to learn more about plaques, tangles, and other features of Alzheimer’s disease. They can now visualize beta-amyloid associated with plaques by imaging the brains of living individuals. Scientists are also exploring the very earliest steps in the disease process. Findings from these studies will help them understand the causes of Alzheimer’s. One of the great mysteries of Alzheimer’s disease is why it largely strikes older adults. Research on how the brain changes normally with age is shedding light on this question. For example, scientists are learning how age-related changes in the brain may harm neurons and contribute to Alzheimer’s damage. These age-related changes include atrophy (shrinking) of certain parts of the brain, inflammation, the production of unstable molecules called free radicals, and mitochondrial dysfunction (a breakdown of energy production within a cell).
[h=3] Genetics[/h] Early-onset Alzheimer’s is a rare form of the disease. It occurs in people age 30 to 60 and represents less than 5 percent of all people who have Alzheimer’s disease. Most cases of early-onset Alzheimer’s are familial Alzheimer’s disease, caused by changes in one of three known genes inherited from a parent. Most people with Alzheimer’s disease have “late-onset” Alzheimer’s, which usually develops after age 60. Many studies have linked the apolipoprotein E (APOE) gene to late-onset Alzheimer’s. This gene has several forms. One of them, APOE ε4, seems to increase a person’s risk of getting the disease. However, carrying the APOE ε4 form of the gene does not necessarily mean that a person will develop Alzheimer’s disease, and people carrying no APOE ε4 can also develop the disease. Most experts believe that additional genes may influence the development of late-onset Alzheimer’s. Scientists around the world are searching for these genes, and have identified a number of common genes in addition to APOE ε4 that may increase a person’s risk for late-onset Alzheimer’s. For more about this area of research, see NIA's Alzheimer’s Disease Genetics Fact Sheet.
[h=3] Environmental/Lifestyle Factors[/h] Research also suggests that a host of factors beyond basic genetics may play a role in the development and course of Alzheimer’s disease. There is a great deal of interest, for example, in associations between cognitive decline and vascular and metabolic conditions such as heart disease, stroke, 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 conditions may help with Alzheimer’s as well. Further, a nutritious diet, physical activity (PDF, 871K), social engagement, and mentally stimulating pursuits can all help people stay healthy as they age. New research suggests the possibility that these and other factors also might help to reduce the risk of cognitive decline and Alzheimer’s disease. Clinical trials of specific interventions are underway to test some of these possibilities.
[h=2] Diagnosing Alzheimer’s Disease[/h] Alzheimer’s disease can be definitively diagnosed only after death, by linking clinical measures with an examination of brain tissue and pathology in an autopsy. But doctors now have several methods and tools to help them determine fairly accurately whether a person who is having memory problems has “possible Alzheimer’s dementia” (dementia may be due to another cause) or “probable Alzheimer’s dementia” (no other cause for dementia can be found). To diagnose Alzheimer’s, doctors may:
Ask questions about overall health, past medical problems, ability to carry out daily activities, and changes in behavior and personality
Conduct tests of memory, problem solving, attention, counting, and language
Carry out standard medical tests, such as blood and urine tests, to identify other possible causes of the problem
Perform brain scans, such as computed tomography (CT) or magnetic resonance imaging (MRI), to distinguish Alzheimer’s from other possible causes for symptoms, like stroke or tumor
These tests may be repeated to give doctors information about how the person’s memory is changing over time. Early, accurate diagnosis is beneficial for several reasons. It can tell people whether their symptoms are from Alzheimer’s or another cause, such as stroke, tumor, Parkinson’s disease, sleep disturbances, side effects of medications, or other conditions that may be treatable and possibly reversible. Beginning treatment early on in the disease process can help preserve function for some time, even though the underlying disease process cannot be changed. Having an early diagnosis also helps families plan for the future, make living arrangements, take care of financial and legal matters, and develop support networks. In addition, an early diagnosis can provide greater opportunities for people to get involved in clinical trials. In a typical clinical trial, scientists test a drug or treatment to see if that intervention is effective and for whom it would work best. http://www.nia.nih.gov/alzheimers/publication/alzheimers-disease-fact-sheet
