Trouble sleeping? It may affect your memory later on
The amount and quality of sleep you get at night may affect your memory later in life, according to research that was released today and will be presented at the American Academy of Neurology’s 64th Annual Meeting in New Orleans April 21 to April 28, 2012.
“Disrupted sleep appears to be associated with the build-up of amyloid plaques, a hallmark marker of Alzheimer’s disease, in the brains of people without memory problems,” said study author Yo-El Ju, MD, with Washington University School of Medicine in St. Louis and a member of the American Academy of Neurology. “Further research is needed to determine why this is happening and whether sleep changes may predict cognitive decline.”
Researchers tested the sleep patterns of 100 people between the ages of 45 and 80 who were free of dementia. Half of the group had a family history of Alzheimer’s disease. A device was placed on the participants for two weeks to measure sleep. Sleep diaries and questionnaires were also analyzed by researchers.
After the study, it was discovered that 25 percent of the participants had evidence of amyloid plaques, which can appear years before the symptoms of Alzheimer’s disease begin. The average time a person spent in bed during the study was about eight hours, but the average sleep time was 6.5 hours due to short awakenings in the night.
The study found that people who woke up more than five times per hour were more likely to have amyloid plaque build-up compared to people who didn’t wake up as much. The study also found those people who slept “less efficiently” were more likely to have the markers of early stage Alzheimer’s disease than those who slept more efficiently. In other words, those who spent less than 85 percent of their time in bed actually sleeping were more likely to have the markers than those who spent more than 85 percent of their time in bed actually sleeping.
SLEEP HELPS REINFORCE MEMORY
A new study claims the best way to remember something important is to remember it while you are asleep.
The research in this week’s Nature Neuroscience, claims reactivating newly learned memories during sleep rather than when awake does a better job of strengthening the memory trace.
The work, led by Björn Rasch of the University of Basel in Switzerland could have clinical implications for treating disorders such as post traumatic stress disorder (PTSD).
The research involved training subjects in a spatial memory task to learn an object’s location in a grid. At the same time an odor was released - the idea being to associate the memory with the smell.
-Stuart Gary and Darren Osborne, ABC Science Online
“The association between disrupted sleep and amyloid plaques is intriguing, but the information from this study can’t determine a cause-effect relationship or the direction of this relationship. We need longer-term studies, following individuals’ sleep over years, to determine whether disrupted sleep leads to amyloid plaques, or whether brain changes in early Alzheimer’s disease lead to changes in sleep,” Ju said. “Our study lays the groundwork for investigating whether manipulating sleep is a possible strategy in the prevention or slowing of Alzheimer disease.”
Sleep Boosts Memory
“Let me sleep on it” may just be the right advice for remembering complex information. Getting a good night’s rest not only helps retention, but may even help us recall thoughts forgotten during the day, according to researchers from the University of Chicago.
Howard Nusbaum, a professor of psychology at the university, studied the effects of sleep on memory by testing the retention of words. Using a synthesizer, he distorted tapes of recorded speech, making the words difficult to understand. He then played the tapes back to college students, asking them to decipher the speech.
On first exposure, students understood just 21 percent of the words. After an hour of training, they understood 54 percent. “It is something like learning how to understand someone with a foreign accent,” explains Nusbaum.
He then ran the same experiment with a second group of students, who were tested first at 9 in the morning and then tested again at 9 that night. This group remembered only remembered 31 percent of the words in the test at the end of the day. Yet after a night of sleep, their scores climbed up again: the following morning, the same students remembered 40 percent of the words.
A third group was tested at 9:00 in the evening, then again the next morning. Their retention was also 40 percent.
Apparently, in the process of cleaning up our scattered thoughts, sleep also finds the ones that were about to slip through the cracks. “Sleep might strengthen relevant associations and weaken irrelevant associations, improving access to memories,” Nusbaum notes.
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By Colin Allen
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The study was supported by the Ellison Foundation and the National Institutes of Health.
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Rachel Seroka
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651-695-2738
American Academy of Neurology