Poor sleep causes memory to fail in older people, and improving the quality of sleep could restore recall as well, a new study suggests.
Sleep plays an important role in the consolidation of memories, moving information from temporary to permanent storage areas of the brain.
When older people are unable to get a good night’s rest, memory consolidation gets interrupted.
Long-term memories are formed when the brain produces two kinds of electrical waves to create deep REM sleep, but aging brains struggle to keep the two kinds of waves in sync.
New research from the University of California, Berkeley, demonstrated a link between the ability to recall information, and the quality of nightly sleep, suggesting that if sleep could be improved, the effects of dementia might be reduced too.
Older brains struggle to keep two brain waves in sync during sleep, and when this coordination is lost, both sleep and memory suffer, according to the new UC Berkeley study
More than 5.5 million Americans suffer from Alzheimer’s, and those numbers are only expected to climb as the population ages.
While much about sleep’s purpose in our survival remains a mystery, we do know that it helps us to solidify memories.
During our waking hours, the hippocampus forms short memories out of the sensory information we take in.
That information is stored as electrical signals, which get replayed during sleep. What information is in each recording determines where in the brain’s outer cortex – which acts like a long-term bookshelf – memories get stored more permanently.
Deep sleep is produced by a pair of coordinating waves of electrical activity. In the new study, published in Neuron, the researchers monitored these waves during the sleep of young and older people.
Before the study participants slept, the Berkeley scientists taught them each 120 pairs of words.
Why sleep is essential to health
The CDC recommends that all adults get at least seven hours of sleep a night.
Getting less than that increases your risk of many diseases, including diabetes, heart disease, Alzheimer’s, stroke, obesity, arthritis, arthritis, asthma, depression and cancer.
While its exact purpose is unclear, sleep helps us consolidate memories, and is signals the brain’s ‘sewage system’ to kick on and remove toxins.
Our bodies also ramp up production of important immune system factors that help us fight cancer an disease.
The World Health Organization even considers night shift work a likely carcinogen because it disrupts production of cancer-killing cells.
The better the coordination between the big slow waves, and the faster ones – called sleep spindles – during sleep, the better the study participants’ recall for the word pairs was in the morning.
The younger group’s waves were, in general, in better sync, while the older participants’ brains struggled to keep time, leading to poorer recall in the morning.
As the brain ages, it begins to atrophy, or shrink as cells start to die. This is a natural part of aging, but the researchers believe that these cell deaths may be causing the lost synchronization and rhythms in older people’s brains.
With age, ‘the brain degrades, some parts even quickly than others, and those are the same regions that help generate and maintain sleep,’ study co-author Dr Matthew Walker told Daily Mail Online in a recent interview.
‘It’s the sad tragedy in aging,’ he says. But he thinks all may not be lost.
‘We’re working toward using electrical brain stimulation to see if we can give back healthy sleep by restoring those big, beautiful, powerful deep brain waves.’
If he and his team can successfully zap brain waves back into rhythm, they might be able to restore the memory-forming abilities of older adults as well.