Featured Research

from universities, journals, and other organizations

Study Boosts Confidence In Potential Screening Tool For Alzheimer’s Disease

Date:
April 24, 2003
Source:
NIH/National Institute Of Mental Health
Summary:
A major study has confirmed the value of potential markers for identifying people with Alzheimer's disease. Scientists at the National Institute of Mental Health (NIMH) found that levels of two key indicators in spinal fluid distinguished clinically diagnosed Alzheimer's patients from controls with 89-92 percent efficiency.

A major study has confirmed the value of potential markers for identifying people with Alzheimer's disease. Scientists at the National Institute of Mental Health (NIMH) found that levels of two key indicators in spinal fluid distinguished clinically diagnosed Alzheimer's patients from controls with 89-92 percent efficiency.

Related Articles


This matches or exceeds current clinical diagnostic methods, such as doctor's evaluation of medical history, cognitive testing, and brain scans. However, the potential telltale signs, or biomarkers, won't be ready for use as predictive and diagnostic tools until completion of long-term studies now underway. Trey Sunderland, M.D., chief, NIMH Geriatric Psychiatry Branch, and colleagues, report on their study -- which included both direct examination of 203 patients and controls and a meta-analysis of world literature -- in the April 23, 2003 Journal of the American Medical Association.

"We're hopeful that biomarkers will eventually be developed to help detect incipient illness in younger people who are at risk but who may not yet show any symptoms," said Sunderland. "Clues from biochemical, genetic and brain imaging studies could point to new possibilities for preventive interventions."

The NIMH study examined cerebrospinal fluid (CSF) levels of two protein fragments, hallmarks of the disease process, found in brains of Alzheimer's victims: beta-amyloid, which clumps together to form brain-damaging plaques, and tau, which strangles neurons in tangled filaments. Like many previous studies, it found that CSF beta amyloid levels drop, while tau levels rise in Alzheimer's. What's new is that the confidence level in this finding has now been boosted by applying a meta-analysis of the world literature and adding "the largest cohort of Alzheimer's disease patients and controls evaluated to date," say the researchers.

To gather their data, Sunderland and colleagues performed spinal taps on 136 Alzheimer's patients and 72 control subjects and measured CSF levels of the suspect protein fragments. As the fluid that bathes the brain, CSF has long been considered the most reliable window available into a living human's neurochemical activity. Beta-amyloid levels in Alzheimer's patients averaged only 183 picograms per milliliter of CSF, compared to 491 in controls. Patients' tau levels dwarfed controls 587 to 224 picograms per milliliter. These differences remained significant even after statistical analysis controlled for effects of age and sex. Taken together the two markers distinguished clinically diagnosed Alzheimer's patients from controls with a sensitivity of 92 percent and a specificity of 89 percent.

Years of education were associated with lower CSF tau levels among Alzheimer's patients, suggesting a possible protective factor. Evidence suggests that the changes in beta-amyloid and tau levels may be present early in the disease process.

The researchers also performed a meta-analysis of 51 similar studies, totaling 3133 Alzheimer's patients and 1481 controls. These included 17 controlled studies of beta-amyloid winnowed from 188 articles, and 34 studies of tau, sifted from an initial list of 200 articles. Of the beta-amyloid studies, 14 of the 17 found the same pattern seen in the NIMH sample. All of the tau studies showed the same pattern as the NIMH sample.

However, for both measures, the researchers found considerable overlap in levels between the Alzheimer's and control groups. "It is evident that the diagnostic sensitivity and specificity of these individual CSF beta-amyloid and tau assays is simply not sufficient to warrant general clinical use of these biomarkers for individual use," they caution. They call for additional studies to standardize assay methodology, and for "real world" comparisons between Alzheimer's patients and people with other forms of dementia, noting that these would likely show even more overlap.

"Perhaps the most important future use for such biomarkers is in the prospective study of people at risk for developing Alzheimer's disease," noted Sunderland. "By establishing a person's baseline and tracking levels over time, we might be able to interpret gradual changes as a sign that he or she is developing the disorder."

Also participating in the research were: Robert M. Cohen, M.D., Ph.D., Gary Linker, M.D., Nadeem Mirza, M.D., Karen Putnam, Judy Bergeson, M.A, Guy Manetti, Matthew Zimmerman, Brian Tang, NIMH; David Friedman, Ph.D., Lida Kimmel, M.S., Pfiser Pharmaceuticals; John Bartko, Ph.D., consultant statistician.

NIMH is part of the National Institutes of Health (NIH), the Federal Government's primary agency for biomedical and behavioral research. NIH is a component of the U.S. Department of Health and Human Services.


Story Source:

The above story is based on materials provided by NIH/National Institute Of Mental Health. Note: Materials may be edited for content and length.


Cite This Page:

NIH/National Institute Of Mental Health. "Study Boosts Confidence In Potential Screening Tool For Alzheimer’s Disease." ScienceDaily. ScienceDaily, 24 April 2003. <www.sciencedaily.com/releases/2003/04/030424082627.htm>.
NIH/National Institute Of Mental Health. (2003, April 24). Study Boosts Confidence In Potential Screening Tool For Alzheimer’s Disease. ScienceDaily. Retrieved March 4, 2015 from www.sciencedaily.com/releases/2003/04/030424082627.htm
NIH/National Institute Of Mental Health. "Study Boosts Confidence In Potential Screening Tool For Alzheimer’s Disease." ScienceDaily. www.sciencedaily.com/releases/2003/04/030424082627.htm (accessed March 4, 2015).

Share This


More From ScienceDaily



More Mind & Brain News

Wednesday, March 4, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Former NFL Players Donate Brains to Science

Former NFL Players Donate Brains to Science

Reuters - US Online Video (Mar. 3, 2015) Super Bowl champions Sidney Rice and Steve Weatherford donate their brains, post-mortem, to scientific research into repetitive brain trauma. Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Alzheimer's Protein Plaque Found In 20-Year-Olds

Alzheimer's Protein Plaque Found In 20-Year-Olds

Newsy (Mar. 3, 2015) Researchers found an abnormal protein associated with Alzheimer&apos;s disease in the brains of 20-year-olds. Video provided by Newsy
Powered by NewsLook.com
This Nasal Treatment Could Help Ease Migraine Pain

This Nasal Treatment Could Help Ease Migraine Pain

Newsy (Mar. 2, 2015) Researchers gave lidocaine to 112 patients, and about 88 percent of the subjects said they needed less migraine-relief medicine the next day. Video provided by Newsy
Powered by NewsLook.com
How Facebook Use Can Lead To Depression

How Facebook Use Can Lead To Depression

Newsy (Mar. 1, 2015) Margaret Duffy of the University of Missouri talks about her study on the social network and the envy and depression that Facebook use can cause. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins