Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Early warning signs of Alzheimer’s show up across cognitive areas years before official diagnosis

01.08.2005


Swedish meta-analysis of 47 scientific studies finds clear patterns across thousands of people who went on to be diagnosed with the disease



By combing through dozens of Alzheimer’s disease (AD) studies, psychologists have gained a clear picture of cognitive problems in people who will develop the degenerative brain disease. The meta-analysis reveals that people can show early warning signs across several cognitive domains years before they are officially diagnosed, confirming that Alzheimer’s causes general deterioration and tends to follow a stable preclinical stage with a sharp drop in function. The findings appear in the July issue of Neuropsychology, which is published by the American Psychological Association.

Researchers at the Karolinska Institute and Stockholm Gerontology Research Center, affiliated also with the Max Planck Institute for Human Development and the University of South Florida, crunched the data from a decade’s worth of studies: Published reports that met stringent criteria had records on 1,207 people with preclinical Alzheimer’s (they later developed the disease) and 9,097 controls who stayed healthy.


Neuropsychologists are striving to understand the preclinical stage for two reasons: On the theoretical level, understanding the transition from normal aging to dementia is vital to understanding how the disease evolves. On the clinical level, treatment can work best when doctors can identify at-risk individuals as early as possible.

The authors studied 47 peer-reviewed studies published between January 1985 and February 2003. The year 1985 marked the introduction of more systematic and reliable diagnostic criteria for Alzheimer’s.

The analysis showed that no matter what kind of study, people at the preclinical stage showed marked preclinical deficits in global cognitive ability, episodic memory, perceptual speed, and executive functioning; along with somewhat smaller deficits in verbal ability, visuospatial skill, and attention. There was no preclinical impairment in primary memory.

The generalized nature of the problem is consistent, say the authors, with recent observations that multiple brain structures and functions are affected long before the AD diagnosis. They remind readers that the deficits seen in preclinical AD mirror quite closely those seen in normal aging, such as impairments in episodic memory, executive functioning, and cognitive speed. Still, says lead author Lars Bäckman, PhD, these problems are exacerbated in those who will go on to be diagnosed with dementia.

He explains, "There are no clear qualitative differences in patterns of cognitive impairment between the normal old 75-year old and the preclinical AD counterpart. Rather, we think of the normal elderly person, the preclinical AD person, and the early clinical AD patient as representing three instances on a continuum of cognitive capabilities. This presents an obvious challenge for accurate early diagnosis."

The data also supported the emerging consensus that AD’s preclinical period is characterized by an early onset followed by relative stability until a few years before diagnosis, when functioning plummets.

Bäckman and his colleagues endorse a multi-variable approach to understanding the preclinical stage of AD because this approach will help clinicians to more accurately predict the likelihood of disease.

The study traced other interesting patterns. People younger than 75 years at baseline were more impaired at the outset than people older than 75 at baseline. Impairment was also greater for the patients with shorter periods (fewer than three years) to diagnosis. These findings suggest that preclinical impairment is greater when the disease starts younger and progresses more quickly, due to more widespread and severe brain lesions among younger cases.

Pam Willenz | EurekAlert!
Further information:
http://www.apa.org

More articles from Health and Medicine:

nachricht Highly precise wiring in the Cerebral Cortex
21.09.2017 | Max-Planck-Institut für Hirnforschung

nachricht PET imaging tracks Zika virus infection, disease progression in mouse model
20.09.2017 | US Army Medical Research Institute of Infectious Diseases

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: 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...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

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

Glycosylation: Mapping Uncharted Territory

21.09.2017 | Life Sciences

Highly precise wiring in the Cerebral Cortex

21.09.2017 | Health and Medicine

Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?

21.09.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>