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!
Nanoparticles as a Solution against Antibiotic Resistance?
15.12.2017 | Friedrich-Schiller-Universität Jena
Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences