Smoking pot may stave off Alzheimer’s

[waltky]

Dementia autopsies revealing some clues...

Sharp-witted elderly shed insight on dementia
Sun., Nov. 16, 2008 : Autopsy analysis of ‘super aged’ brains shows fewer protein tangles

People who manage to keep a razor-sharp memory well into their 80s appear to have fewer fiber-like tangles of a protein linked with Alzheimer's than those who age normally, U.S. researchers said on Sunday. Lower levels of this protein, known as tau, appear to be a critical factor in maintaining memory skills, they said. "It was always assumed that the accumulation of these tangles is a progressive phenomenon through the aging process," Changiz Geula of Northwestern University's Feinberg School of Medicine in Chicago, said in a statement.

"But we are seeing that some individuals are immune to tangle formation and that the presence of these tangles seems to influence cognitive performance," said Geula, who is presenting his findings at a Society for Neuroscience meeting in Washington. While most studies of memory and aging involve people with some form of cognitive decline, Geula studied the so-called "super-aged," or those who maintain sharp cognitive skills in advanced age. The researchers studied the brains of five deceased people considered super-aged because of their high scores on memory tests at age 80, and compared them to the brains of elderly individuals who had no signs of dementia.

They found far fewer tau tangles in those who had sharp memories than those with normal memories for their age. Curiously, the number of sticky plaques made of beta amyloid — considered a hallmark of Alzheimer's disease — was about the same in both groups. While tau protein accumulates inside brain cells, forming fibrous tangles that eventually cause the cell to burst, beta-amyloid plaques accumulate outside the brain cell, disrupting cell-to-cell communication.

Alzheimer's disease shows plaques and tangles

[waltky]

Herbal remedy ineffective...

Ginkgo Biloba Ineffective Against Dementia, Researchers Find
November 18, 2008 - The largest and longest independent clinical trial to assess ginkgo biloba’s ability to prevent memory loss has found that the supplement does not prevent or delay dementia or Alzheimer’s disease, researchers are reporting.

The study is the first trial large enough to accurately assess the plant extract’s effect on the incidence of dementia, experts said, and the results dashed hopes that it is an effective preventative. In fact, there were more cases of dementia among participants who were taking ginkgo biloba than among those who were taking a placebo, though the difference was not statistically significant. “We were disappointed,” said Dr. Steven T. DeKosky, dean of the School of Medicine at the University of Virginia and the principal investigator. “We were hopeful this would work.” The study appears in Wednesday’s issue of The Journal of the American Medical Association.

For the trial, researchers from five academic medical centers in the United States recruited 3,069 community volunteers 75 and older. Most were cognitively normal, but 482 had mild cognitive impairment. About half were given two doses of 120 milligrams of ginkgo biloba extract daily, while the other half were provided with placebo pills. Neither the participants nor the doctors knew who was receiving which pills. They were followed for a median of 6.1 years and assessed every six months for dementia. During the study period, 523 cases of dementia were diagnosed. Of those, 246, or 16.1 percent, were in placebo users, and 277, or 17.9 percent, were in people taking ginkgo biloba.

“If this was really a powerful effect, we would have seen something that would have at least inched its way toward statistical significance,” Dr. DeKosky said. “If you’re in your mid-70s and want to take this drug to protect yourself from developing the disease, my comment is: ‘It doesn’t work.’ ” An editorial accompanying the study warned not only that the extract was unhelpful, but also that it might be harmful. The trial reported more hemorrhagic strokes among ginkgo users, though the difference was not statistically significant, while patients with cardiovascular disease who took the supplement also faced an increased risk of dementia. “There is nothing here, no signal of any effect,” said Dr. Lon Schneider, director of the Alzheimer’s Disease Research and Clinical Center at the University of Southern California, who wrote the editorial.

MORE

[waltky]

Catching dementia early...

Simple test may catch early signs of dementia
Wed., Nov. 26, 2008 - Study: Questions on daily functioning ability can help predict mental decline

A short, simple screening test has shown early promise in detecting milder mental impairment in older adults, before they've progressed to dementia. Many older people who ultimately develop Alzheimer's disease first go through a period of what doctors call mild cognitive impairment. There is no hard definition of this phase, but in general it means that a person has some memory loss or other signs of cognitive decline but no serious problems in day-to-day functioning.

Because the changes are subtle, mild cognitive impairment often goes unrecognized, and there is no simple test for detecting it. Ideally, though, experts want such a test — a quick screen that primary care doctors can use routinely, akin to checking cholesterol or blood pressure levels. In the new study, researchers tested a screening instrument they've developed to do just that. It is a combination of a few simple tasks that assess older adults' memory and a set of questions on their day-to-day functioning — whether they can take care of things like shopping and making meals.

They found that among the 204 older adults they studied, the test was able to correctly classify people as cognitively healthy, mildly impaired or suffering from dementia 83 percent of the time. That accuracy rate is "pretty good," said researcher Dr. James J. Lah, principal investigator at Emory University in Atlanta — particularly considering that the screening is simple. The cognitive testing takes a few minutes, Lah told Reuters Health, and the questions on daily functioning — intended to be completed by a family member — are similarly easy. In addition, he said, primary care doctors can administer and score the test with minimal training.

More Simple test may catch early signs of dementia - Aging- msnbc.com

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Cold sore link to Alzheimer's...

Cold sores 'an Alzheimer's risk'
Monday, 8 December 2008 - Catching a cold sore puts you at risk of Alzheimer's disease, mounting evidence suggests.

The herpes virus behind cold sores is a major cause of the protein plaques that accumulate in the brains of people with Alzheimer's, scientists have shown. On the plus side, the latest discovery by the University of Manchester team may mean antiviral drugs used to treat cold sores could also prevent dementia. The findings are published in the Journal of Pathology. "This could lead to new treatments for Alzheimer's, based on existing antiviral agents" - Rebecca Wood of the Alzheimer's Research Trust

Professor Ruth Itzhaki and colleagues found DNA evidence of the herpes simplex virus (HSV) type 1 in 90% of plaques in Alzheimer's disease patients' brains. They had previously shown that HSV1 infection of nerve-type cells in mice leads to deposition of the main component of the plaques - beta amyloid. And that the virus is present in the brains of many elderly people and that in those people with a specific genetic factor, there is a high risk of developing Alzheimer's disease.

Taken together, the researchers say the findings strongly implicate the cold sore-causing virus as a root cause of Alzheimer's dementia. Professor Itzhaki said: "We suggest that HSV1 enters the brain in the elderly as their immune systems decline and then establishes a dormant infection from which it is repeatedly activated by events such as stress, immunosuppression, and various infections."

Cell damage

[waltky]

Check that BP...

High BP may decrease older adults' ability to think clearly
Washington, Dec 16,`08 : Researches at North Carolina State University have found that increased blood pressure in older adults is directly related to decreased cognitive functioning.

The finding is based on a study, which indicates that stressful situations may make it more difficult for some seniors to think clearly. In the study, Dr. Jason Allaire, an assistant professor of psychology at NC State who co-authored the study, found that study subjects whose average systolic blood pressure was 130 or higher saw a significant decrease in cognitive function when their blood pressure spiked.

However, Allaire also found that study subjects whose average blood pressure was low or normal saw no change in their cognitive functioning - even when their blood pressure shot up. Allaire said the study shows a link between blood pressure spikes in seniors with high blood pressure and a decrease in their inductive reasoning.

"Inductive reasoning is important because it is essentially the ability to work flexibly with unfamiliar information and find solutions," Allaire said. Allaire said that the findings might indicate that mental stress is partially responsible for the increase in blood pressure - and the corresponding breakdown in cognitive functioning. However, Allaire notes that normal fluctuations in blood pressure likely play a role as well.

High BP may decrease older adults' ability to think clearly