Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brain scans may predict cognitive decline in normal people

09.02.2006


Brain scans may detect neurological changes in people who exhibit no outward signs of cognitive decline but who later develop dementia or mental impairment, according to the results of a new study led by researchers at the University of California, Berkeley.



The study, to be published Feb. 8 in the journal Annals of Neurology, provides encouraging evidence that positron emission tomography (PET) and magnetic resonance imaging (MRI) could eventually be used to detect preclinical signs of Alzheimer’s disease.

"Our paper is one of the few to show that it is possible to detect changes in the brains of normal older people who experience subsequent cognitive decline," said Dr. William Jagust, UC Berkeley professor of neuroscience and public health and lead author of the paper. "We don’t have enough data, yet, to say that the brain scans can predict Alzheimer’s disease. However, the locations of the affected brain regions have been associated in other studies with Alzheimer’s, so it’s possible that we are picking up early signs of the disease."


Jagust, who has joint appointments at UC Berkeley’s School of Public Health, the Helen Wills Neuroscience Institute and the Lawrence Berkeley National Laboratory, worked with Mary Haan, professor of epidemiology at the University of Michigan and principal investigator of the Sacramento Area Latino Study on Aging (SALSA).

The brain imaging study is a substudy of SALSA, the first and only representative study of dementia and cognitive functioning in a Latino population. SALSA, funded by the National Institute on Aging, includes 1,789 people, primarily Mexican American, who were recruited by mail, telephone and door-to-door solicitation.

For the imaging substudy, 60 cognitively normal participants received baseline PET and MRI brain scans and underwent a full battery of neuropsychological tests at enrollment. They were followed for an average of 3.8 years, taking cognition and memory tests approximately once a year. Individuals with significant declines in their scores were evaluated further for signs of cognitive decline.

The researchers found that lower glucose metabolism - as determined by the PET scans - was strongly linked to faster declines on the modified mini mental state examination (3MSE), a test that assesses global cognitive functions such as memory, language, spatial ability and judgment.

Specifically, the PET scans detected areas of lower glucose metabolism in the parietal and temporal lobes of the brain, the same regions shown in many other studies to have lower glucose metabolism in Alzheimer’s patients and in some people with mild cognitive impairment.

In the imaging substudy, the MRI scans focused on the entorhinal cortex and hippocampus regions in the temporal lobe of the brain, areas that are involved in memory. Other post-mortem studies of the brains of Alzheimer’s patients indicate that these regions are the first to become affected as the disease develops.

The researchers found that the smaller these brain regions were in the MRI scans, the more an individual’s score declined on the delayed recall (DelRec) memory test. These results are also in line with findings from other studies that link the size of the entorhinal cortex and hippocampus in people with mild cognitive impairment with the eventual development of Alzheimer’s disease.

The researchers point out that the different brain scans predicted declines on different types of cognitive tests. The PET scans predicted declines on the 3MSE, but they did not predict declines on the DelRec memory test. It was the reverse for the MRI scans, which predicted declines on the memory test, but not on the 3MSE.

"These results fit with what we know about the brain," said Jagust. "The brain regions picked up by the PET scans involve more generalized cognitive functions, while the regions studied in the MRI scans are associated with memory."

During the study, five people developed cognitive impairment and one person was diagnosed with Alzheimer’s disease. One of the five who developed cognitive impairment showed the fastest decline on both tests.

"In a project of this size, it’s not realistic to expect the brain scans to predict Alzheimer’s," said Haan. "But there is enough information to say that PET and MRI scans can predict subsequent cognitive decline in a population of cognitively normal people."

The researchers note that prior research on Alzheimer’s focused primarily on people who had already developed mild symptoms of cognitive loss or on post-mortem analyses of the brains of Alzheimer’s patients.

"By the time people who are already sick are identified, it’s often too late to slow down the progression of Alzheimer’s," said Haan. "By identifying early changes that could predict the development of dementia, it may also be possible to link those changes to primary risk factors that could be altered."

According to the National Institutes of Health, approximately 4 million people suffer from Alzheimer’s disease in the United States, and the proportion of people with the disease doubles every five years after the age of 65.

"In the last two to five years, there has been a real explosion of knowledge about the molecular basis of Alzheimer’s that may lead to effective drugs to cure or prevent the disease, and those drugs would likely be more effective the earlier they are given," said Jagust. "That has given a new urgency to research in predicting as early as possible those who will go on to develop Alzheimer’s."

Options are now limited for identifying those who may go on to develop Alzheimer’s disease. Few genetic factors have been identified, and the ones that have are only applicable to a minority of people who go on to develop the disease.

For instance, research has identified an allele that codes for a protein called apolipoprotein E, or apoE, as a major genetic risk factor for Alzheimer’s disease. ApoE is associated with the buildup of beta amyloid plaques in the brain’s nerve cells.

However, researchers estimate that this gene is only present in 15 to 25 percent of populations with Northern European ancestry. Among the Mexican American and Asian American populations, the prevalence is closer to 10 percent.

Meanwhile, research is continuing on identifying other risk factors for mental decline. The SALSA study, for instance, is credited with first identifying type 2 diabetes as a risk factor for dementia and cognitive impairment.

"It’s possible that people of Mexican descent have a higher genetic risk for type 2 diabetes," said Haan. She said that she is investigating whether genes known to be associated with type 2 diabetes are also related to an increased risk in cognitive impairment.

Sarah Yang | EurekAlert!
Further information:
http://www.berkeley.edu

More articles from Health and Medicine:

nachricht New malaria analysis method reveals disease severity in minutes
14.08.2017 | University of British Columbia

nachricht New type of blood cells work as indicators of autoimmunity
14.08.2017 | Instituto de Medicina Molecular

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>