New York University School of Medicine researchers have developed a brain scan-based computer program that quickly and accurately measures metabolic activity in a key region of the brain affected in the early stages of Alzheimer's disease. Applying the program, they demonstrated that reductions in brain metabolism in healthy individuals were associated with the later development of the memory robbing disease, according to a new study.
"This is the first demonstration that reduced metabolic activity in the hippocampus may be used to help predict future Alzheimer's disease," says Lisa Mosconi, Ph.D., a research scientist in the Department of Psychiatry, who developed the computer program and led the new study. "Although our findings need to be replicated in other studies," she says, "our technique offers the possibility that we will be able to screen for Alzheimer's in individuals who aren't cognitively impaired."
How would you like to get a brain scan and then be told that in 5 or 10 years you will start to lose your memory and eventually forget everything thing you know?
Dr. Mosconi and colleagues have recently published the technical details of the program, called "HipMask," in the June 2005 issue of the journal Neurology. She will present the new findings on June 20 at the Alzheimer's Association International Conference on Prevention of Dementia held in Washington.
The computer program is an image analysis technique that allows researchers to standardize and computer automate the sampling of PET brain scans. The NYU researchers hope the technique will enable doctors to measure the metabolic rate of the hippocampus and detect below-normal metabolic activity.
The technique grew out of years of research by Mony de Leon, Ed.D., Professor of Psychiatry and Director of the Center for Brain Health. His group was the first to demonstrate with CT and later with MRI scans that the hippocampus, a sea-horse shaped area of the brain associated with memory and learning, diminishes in size as Alzheimer's disease progresses from mild cognitive impairment to full-blown dementia.
Yet until now there has been no reliable way to accurately and quickly measure the hippocampal area of the brain on a PET scan. The hippocampus is small and its size and shape are affected greatly in individuals with Alzheimer's, making it difficult to sample this region. HipMask is a sampling technique that uses MRI to anatomically probe the PET scan.
MRI relies on electromagnetic energy to excite water molecules in the brain to create an anatomical map of the brain. The MRI was used in the study to determine the total volume of the hippocampus and then to define that portion (namely the HipMask) that was shared by all persons regardless of their disease status. PET employs radioactively labeled glucose to show the brain at work and the HipMask was applied to these scans to derive estimates of the hippocampal glucose metabolism.
The researchers followed 53 healthy, normal subjects between the ages of 54 and 80 for at least 9 years and in some cases for as long as 24 years. All subjects received two FDG-PET scans -- one at baseline and a follow-up after 3 years. Thirty individuals had a second follow-up scan after another seven years. Altogether there were 136 PET scans.
The researchers applied the HipMask to all 136 scans. The results showed that hippocampal glucose metabolism, as determined by the HipMask, was significantly reduced 15% to 40% on the first scan, compared to controls, of those 25 individuals who would later experience cognitive decline related to either mild cognitive impairment or to Alzheimer's. The researchers found that the baseline hippocampal glucose metabolism was the only brain or clinical measure that predicted the future cognitive decline.
"Right now, we can show with great accuracy who will develop Alzheimer's nine years in advance of symptoms, and our projections suggest we might be able to take that out as far as 15 years," says Dr. de Leon, whose longitudinal study is funded by the National Institutes of Health (NIH).
"Our basic results will need to be replicated in other studies and expanded to include PET data from diverse patient groups," adds Dr. De Leon. "But we're confident this is a strong beginning, demonstrating accurate detection of early Alzheimer's disease. Now we have a better tool to examine disease progression, and we anticipate this might open some doors to prevention treatment strategies."
Most people are not going to get brain PET scans. The greater value of this finding is in research on methods to prevent or delay the onset of Alzheimer's Disease.
Don't wait for that PET scan result to come back with bad news. Reduce your risk of Alzheimers.
People who drink fruit or vegetable juice at least three times a week seem four times less likely to develop Alzheimer's than nonjuice drinkers, according to a study of 1,800 elderly Japanese Americans. The theory is that juice contains high levels of polyphenols, compounds that may play a brain-protective role.
Less education, gum disease early in life, or a stroke were more important than genes in determining who got dementia, concluded a study of 100 dementia patients with healthy identical twins. Education stimulates neuronal growth; gum disease is a marker of brain-harming inflammation.
Middle-aged sons and daughters of people with Alzheimer's disease may be able to reduce their risk of getting the disorder through lifestyle measures such as exercise, avoiding gum disease, moderate alcohol consumption, and drinking fruit and vegetable juice, according to new research.
Keep your teeth clean. Drink some V-8 or pure fruit juice. Get regular exercise. They'll all protect your brain.
A new study of dementia in identical twins suggests that exposure to inflammation early in life quadruples one's risk of developing Alzheimer's disease.
Margaret Gatz, lead author and professor of psychology in the USC College of Letters, Arts and Sciences, is slated to present her findings at the first Alzheimer's Association International Conference on Prevention of Dementia, to be held June 18-21 in Washington, D.C.
If confirmed, the link would add inflammatory burden to the short list of preventable risk factors for Alzheimer's.
Previous studies by Gatz and others have shown that Alzheimer's is strongly genetic: If one twin has the disease, his or her identical twin has a 60 percent chance of developing it.
Stroke and a short period of formal education both increase the odds of dementia, but not of Alzheimer's specifically, the new study found.
Dementia is an umbrella term for many conditions, including Alzheimer's.
"People can plan a life span that will alter dementia risk," Gatz said. "And these aren't risk factors that are unique to dementia. Many of these are also risk factors for other disorders. This is good news."
Gatz's team, which included researchers from the Karolinska Institute in Stockholm, Sweden, sifted the 20,000 participants in the Swedish Twin Registry for the 109 "discordant" pairs where only one twin had been diagnosed with dementia.
Information about participants' education, activities and health history came from surveys they completed in the 1960s, when the registry was created, and from hospital discharge records.
The surveys included questions about loose or missing teeth. Gatz and colleagues used the answers to build a crude indicator of periodontal disease.
"We're talking about gum disease, but it was measured by teeth lost or loose," Gatz said. "It's not perfect. Given it's not perfect, it's even more striking that it's such a solid risk factor."
The conclusion is not that good oral health can prevent Alzheimer's, but that an inflammatory burden early in life, as represented by chronic gum disease, may have severe consequences later.
I think that previous sentence is poorly worded. Surely good oral health will reduce the risk of Alzheimer's. Poor oral health is not the only souce of inflammatory burden. But it is one big source.
Gatz was inspired to focus on inflammation by the work of USC gerontologists Caleb Finch and Eileen Crimmins, who published a paper in the journal Science linking today's record life spans to lower rates of childhood infectious diseases, such as gum disease, flu, rheumatic fever, tuberculosis and other illnesses.
Such diseases are often preventable, raising hope for prevention of Alzheimer's.
"If what we're indexing with periodontal disease is some kind of inflammatory burden, then it is probably speaking to general health conditions," Gatz said. "There was in our twins quite a lot of periodontal disease, and at that time in Sweden there was a lot of poverty."
The study, titled "Potentially Modifiable Risk Factors From Dementia: Evidence From Identical Twins," also found that mental activities at age 40, such as reading or attending cultural events, did not seem to lower the risk of developing Alzheimer's.
So crossword puzzles do not help. Then I guess writing a blog isn't going to help either. Heavy sigh.
Previous reports have suggested a link between education and lowered risk of Alzheimer's. But when education is controlled for by using twins with different levels of education then the education effect becomes very low. One possible explanation might be that level of education is a proxy for level of intelligence. Higher intelligence people might be more likely to avoid behaviors (like eating junk food or not practicing good dental hygeine) than lower intelligence people. Or perhaps having smarter brains allows a person to deteriorate for longer from a higher level of initial cognitive function before the effects of Alzheimer's become apparent.
Participants who had more education than their twins were at slightly lower risk of developing dementia, but the influence of education on Alzheimer's risk was statistically negligible."Once one controls for genes, the level of education is not a huge risk factor," said Gatz, who questioned popular attitudes linking Alzheimer's or dementia to mental inactivity.
Drinking soda leads to tooth decay. So if you don't want your kids to get Alzheimer's Disease in their old age then do not let them drink soda.
|Share |||Randall Parker, 2005 June 20 12:33 AM Brain Alzheimers Disease|