Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plaques detected in brain scans forecast cognitive impairment

11.03.2014

Brain imaging using radioactive dye can detect early evidence of Alzheimer's disease that may predict future cognitive decline among adults with mild or no cognitive impairment, according to a 36-month follow-up study led by Duke Medicine.

The national, multicenter study confirms earlier findings suggesting that identifying silent beta-amyloid plaque build-up in the brain could help guide care and treatment decisions for patients at risk for Alzheimer's. The findings appeared online March 11, 2014, in Molecular Psychiatry, a Nature Publishing Group journal.

"Our research found that healthy adults and those with mild memory loss who have a positive scan for these plaques have a much faster rate of decline on memory, language and reasoning over three years," said lead author P. Murali Doraiswamy, M.D., professor of psychiatry and director of the neurocognitive disorders program at Duke.

Alzheimer's disease – which currently has no cure – afflicts an estimated five million U.S. adults, and is the sixth-leading cause of death among adults, according to the Centers for Disease Control and Prevention. Prior studies have found that changes in the brain begin years, and possibly decades, before cognitive symptoms emerge.

... more about:
»Alzheimer's »PET »Plaques »cognitive »scans

A biomarker that could accurately identify those at greatest risk for cognitive decline could help clinicians better evaluate and treat patients, while also accelerating the testing of drugs to treat the disease.

The current study, which enrolled 152 adults ages 50 and older, was designed to assess whether silent pathological changes in the brain associated with Alzheimer's and detected with positron emission tomography (PET) can predict cognitive decline. Of the participants, 69 had normal cognitive function at the start of the study, 52 had been recently diagnosed with mild cognitive impairment, and 31 were diagnosed with Alzheimer's disease.

Subjects completed cognitive tests and underwent PET scans of their brains. This type of imaging uses a radioactive tracer to look for chemical signs of disease in specific tissues.

The radioactive dye used, florbetapir (Amyvid), was approved by the U.S. Food and Drug Administration in 2012 for PET imaging of the brain to estimate beta-amyloid plaque density in patients being evaluated for cognitive impairment. It binds to the beta-amyloid plaques that characterize Alzheimer's disease, helping to measure the extent to which plaques have formed in different brain regions. Using this information, the researchers rated the PET scans as positive or negative.

After 36 months, the researchers repeated the same cognitive exams to reassess participants. They found that those with mild or no cognitive impairment who had evidence of plaques at the trial's start worsened to a greater degree on cognitive tests than those with negative scans.

Thirty-five percent of plaque-positive participants who started with mild cognitive impairment progressed to Alzheimer's, compared to 10 percent without plaque. In addition, plaque-positive participants with mild impairment were more than twice as likely to be started on cognitive-enhancing medication than those without plaque.

Conversely, those with negative scans experienced much less decline: 90 percent of participants with mild cognitive impairment but no plaque did not progress to Alzheimer's. This finding supports the negative predictive value of using PET imaging to identify patients unlikely to decline, which has important implications for both clinical research and treatment.

"Having a negative scan could reassure people that they are not likely to be at risk for progression in the near future," Doraiswamy said.

Doraiswamy cautioned that florbetapir is currently not approved to predict the development of dementia and is not used as a screening tool in cognitively normal people. Future longitudinal studies are needed to further clarify the prognostic role of beta-amyloid plaque PET imaging in a clinical setting.

"Even though our study suggests the test has predictive value in normal adults, we still need additional evidence," Doraiswamy said. "We need longer-term studies to look at the consequences of silent brain plaque build-up, given that it affects 15 to 30 percent of normal older people."

Doraiswamy added that the findings provide support for planned and ongoing multicenter clinical trials of asymptomatic older adults with plaque-positive scans. The research also has implications for other conditions where amyloid might play a role, such as traumatic brain injury (from sports or combat).

###

In addition to Doraiswamy, study authors include Terence Z. Wong of Duke (currently at the University of North Carolina at Chapel Hill); Reisa A. Sperling and Keith Johnson of Massachusetts General Hospital, Harvard Medical School; Eric M. Reiman of Banner Alzheimer's Institute; Marwan N. Sabbagh of Banner-Sun Health Research Institute; Carl H. Sadowsky of Nova SE University; Michael Grundman of Global R&D Partners and the University of California, San Diego; Adam S. Fleisher of Banner Alzheimer's Institute and the University of California, San Diego; and Alan Carpenter, Abhinay D. Joshi, Ming Lu, Mark A. Mintun, Daniel M. Skovronsky and Michael J. Pontecorvo of Avid Radiopharmaceuticals.

The study was funded by Eli Lilly/Avid Radiopharmaceuticals, which markets florbetapir, and was conducted by Avid and the AV45-A11 study group, a consortium of Alzheimer's clinical research centers. Doraiswamy receives advisory and speaker fees from Lilly/Avid, as well as other companies. A full list of author disclosures can be found in the manuscript.

Rachel Harrison | EurekAlert!
Further information:
http://www.dukemednews.org/

Further reports about: Alzheimer's PET Plaques cognitive scans

More articles from Health and Medicine:

nachricht Usher syndrome: Gene therapy restores hearing and balance
25.09.2017 | Institut Pasteur

nachricht MRI contrast agent locates and distinguishes aggressive from slow-growing breast cancer
25.09.2017 | Case Western Reserve University

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: LaserTAB: More efficient and precise contacts thanks to human-robot collaboration

At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.

Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Fraunhofer ISE Pushes World Record for Multicrystalline Silicon Solar Cells to 22.3 Percent

25.09.2017 | Power and Electrical Engineering

Usher syndrome: Gene therapy restores hearing and balance

25.09.2017 | Health and Medicine

An international team of physicists a coherent amplification effect in laser excited dielectrics

25.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>