Cognitive fluctuations include excessive daytime sleepiness, staring into space and disorganized or illogical thinking.
"If you have these lapses, they don't by themselves mean that you have Alzheimer's," says senior author James Galvin, M.D., a Washington University neurologist at Barnes-Jewish Hospital. "Such lapses do occur in healthy older adults. But our results suggest that they are something your doctor needs to consider if he or she is evaluating you for problems with thinking and memory."
The study appears in the Jan. 19 issue of Neurology.
Earlier research had associated cognitive fluctuations with another form of dementia called dementia with Lewy bodies, but little information existed on the potential for links between Alzheimer's and such lapses.
Data for the new study came from Alzheimer's disease evaluations of 511 older adults with memory problems. Average age of the participants was 78. Researchers gave participants standard tests of thinking and memory skills. They also interviewed participants and a family member, checking for prolonged daytime sleepiness, drowsiness or lethargy in spite of sufficient sleep the night before, periods of disorganized or illogical thinking, or instances of staring into space for long periods of time.
A total of 12 percent of the participants had at least three of these symptoms, meeting the criteria for cognitive fluctuations. Those with mental lapses were 4.6 times more likely to be diagnosed with Alzheimer's. Of 216 diagnosed with very mild or mild dementia, 25 had mental lapses; of the 295 with no dementia, only two had mental lapses. In addition, participants with mental lapses did worse on tests of memory and thinking than people without mental lapses.
"We have some ideas about why the biology of dementia with Lewy bodies causes these mental lapses, but nothing comparable for Alzheimer's," Galvin says. "It's possible that some of the patients who were diagnosed with Alzheimer's disease in this study will go on to develop dementia with Lewy bodies, but at the time of the study, they weren't showing any of the Lewy body dementia's core features."
Lewy body dementia, which causes clumps of proteins known as Lewy bodies to form in neurons, is thought to be the second most common form of dementia after Alzheimer's. Clinically, it can overlap with Parkinson's disease and Alzheimer's disease. Pronounced cognitive fluctuations are a hallmark of Lewy body dementia, as are visual hallucinations and rapid eye movement behavior sleep disorder.
Galvin suggests that further study is needed to determine the best way to include mental lapses in diagnostic procedures for Alzheimer's.
Escandon A, Al-Hammadi N, Galvin JE. Effect of cognitive fluctuation on neuropsychological performance in aging and dementia. Neurology, Jan. 19, 2010.
Funding from the National Institute on Aging supported this research.
Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked third in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
Michael C. Purdy | EurekAlert!
Cystic fibrosis alters the structure of mucus in airways
28.06.2017 | University of Iowa Health Care
Mice provide insight into genetics of autism spectrum disorders
28.06.2017 | University of California - Davis
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
28.06.2017 | Physics and Astronomy
28.06.2017 | Physics and Astronomy
28.06.2017 | Health and Medicine