Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

SFVAMC researchers distinguish dementias using brain imaging

12.08.2003


Study suggests hope for better treatment of Alzheimer’s and stroke



Until now, scientists have been unable to distinguish between dementia caused by Alzheimer’s disease and that caused by poor blood flow to the brain. But, researchers at the San Francisco VA Medical Center have now used a combination of magnetic resonance imaging (MRI) and a related technique knows as MR spectroscopy to differentiate between the two kinds of dementia. Their work offers hope of improving the treatment of dementia in patients with poor blood flow, such as stroke victims, and the testing of drugs to treat Alzheimer’s disease (AD).

"Currently, there are no effective treatments for Alzheimer’s disease, but we do have options for treating vascular disease. So, being able to determine that there is a vascular component to a patient’s dementia would make a big difference in planning for treatment," said Norbert Schuff, PhD, a researcher in the Magnetic Resonance Unit at the San Francisco VA Medical Center and a UCSF associate professor of radiology.


The findings of the current study, appearing in the August 12 issue of Neurology, also promise to help speed up the development of new drug therapies for AD. "If we can tell the difference between people with Alzheimer’s and those with vascular dementia, we can select the appropriate candidates for clinical trials of new drugs," said Schuff, who is lead author of the current study.

Alzheimer’s disease, which affects 4 million Americans over the age of 65, is the most common cause of age-related dementia. It is characterized by progressive decline of cognitive functions. The second leading cause of dementia in the United States is the disruption of blood flow to the brain, known as vascular dementia. It affects between 2 and 3 percent of the U.S. population over the age of 65 years, or about 1 million people. Just as poor circulation in the heart leads to heart attacks, restricted blood flow in the brain can lead to strokes of varying severity.

Schuff and his colleagues studied the brains of 43 elderly patients who had been diagnosed with AD and 13 patients who had suffered small strokes below the surface of the brain, and diagnosed with what is called subcortical ischemic vascular dementia, or SIVD. They compared these subjects to 52 cognitively normal elderly subjects.

The researchers used MRI to create three-dimensional images of the patients’ brains in order to look for differences in structure. They also used magnetic resonance spectroscopy to look at the chemical signature of different brain regions. In particular, they looked for a by-product of particular brain cells, called neurons, that make up the wiring of the brain. Active neurons carry electrical signals between different regions of the brain and produce a chemical called N-acetylaspartate, or NAA, which is not produced by other types of brain cells. The amount of NAA in a given region of the brain indicates the level of healthy neurons in that region. A reduction in NAA suggests either neuronal loss or dysfunction.

Researchers found that patients with SIVD had less of the NAA chemical in the region of the brain involved in short-term memory and decision making, called the frontal cortex, when compared to both patients with AD and control subjects. The brains of those with SIVD also had less NAA in the area of the brain involved in language and spatial orientation, called the parietal cortex, when compared to patients with AD and controls. But, SIVD patients had virtually no NAA losses in another brain region involved in memory, called the medial temporal lobe, where patients with AD had substantial NAA deficits.

Accuracy in separating cases of SIVD from AD was improved from 79 percent to 89 percent when researchers added measures taken by MR spectroscopy to measurements taken by conventional MRI.

In patients with SIVD, Schuff and his colleagues also found that lower levels of NAA in outer parts of the brain, called the cortex, were associated with severity of strokes in the layers below the cortex, called white matter. This observation agreed with preliminary findings by other researchers suggesting that SIVD is the result of disconnections between the outer and inner portions of the brain.

This finding suggests that, in patients with SIVD, there may only be neuronal dysfunction rather than neuronal loss, offering hope for recovery of neuronal function in these areas through drug treatment and other forms of therapy, Schuff said. However, there is still the possibility that neuronal loss in SIVD is due to processes indirectly related to stroke that also result in lower NAA. More study in this area will be necessary, Schuff said.

In fact, replication of the current study is also needed, Schuff said. "These patients were very carefully selected. We need to see if this method for distinguishing vascular dementia from Alzheimer’s can be done in a clinical setting where many other factors may contribute dysfunction in the brain," he said.


Additional authors include Michael W. Weiner, MD, director of the Magnetic Resonance Unit (MRU) at the SFVAMC and UCSF professor of radiology, medicine, psychiatry and neurology; Antao Du, MD, and Diane L. Amend, PhD, both researchers of SFVAMC’s MRU; David Norman, MD, UCSF professor of radiology; Joel H. Kramer, PsyD, UCSF clinical associate professor of psychiatry; Bruce L. Miller, MD, UCSF professor of neurology; Kristine Yaffe, MD, SFVAMC chief of geriatric psychiatry and UCSF associate professor of neurology, psychiatry and epidemiology and biostatistics; Bruce R. Reed, MD, UC Davis associate professor of psychiatry; Joseph O’Neill, PhD, UC Los Angeles assistant professor of radiology; William J. Jagust, MD, UC Davis professor and chair of neurology; Helena C. Chui, MD, University of Southern California professor of neurology; and Andres A. Capizzano, MD, of the MRI Unit of Fernandez Hospital, Bueonos Aires, Argentina.

This study was funded by grants from the Department of Veterans Affairs and a grant to the Northern California Institute for Research and Education from the National Institutes of Health.

Camille Mojica Rey | EurekAlert!
Further information:
http://www.ucsf.edu/

More articles from Health and Medicine:

nachricht Researchers release the brakes on the immune system
18.10.2017 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>