Why experts believe deep sleep could stave off dementia 

Several new drugs to treat dementia have made headlines recently, but with concerns about cost – let alone when they become available on the NHS – and worrying possible side effects (such as brain swelling), the news won’t change anything. the lives of those affected today.

However, there may be a much more low-tech approach that could make a more immediate difference for people with early signs of the disease.

Something as simple as getting a good night’s sleep can help older people avoid memory loss from Alzheimer’s disease, the most common form of dementia.

That’s according to new US research published in the journal BMC Medicine, which shows that people with signs of the disease – detected by brain scans rather than symptoms – may be protected against memory loss if they have good, deep sleep.

This news comes as British researchers recently embarked on a project to investigate how improving sleep quality could help improve symptoms in people diagnosed with the disease.

All of this could have important implications for Alzheimer’s treatment, because sleep quality is something you can change – unlike other factors that contribute to dementia, including age (the chance of developing Alzheimer’s doubles every five years). years after you turn 65).

As one of the researchers behind the new US study explains: ‘With a certain level of brain pathology [i.e. changes that indicate disease]you are not destined for cognitive symptoms or memory problems.”

Dr. Zsófia Zavecz, a postdoctoral researcher at UC Berkeley’s Center for Human Sleep Science, told Good Health, “People should be aware that despite a certain level of pathology, there are certain lifestyle factors that help moderate or lessen the effects.” One of those factors is sleep, and deep sleep in particular.’

This is the restorative sleep phase, during which the body repairs itself and stores memories from the day. Alzheimer’s disease is linked to an abnormal buildup of two proteins called amyloid and tau.

Experts believe that over the years, deposits of amyloid — called plaques — build up around brain cells and deposits of tau form knots in the cells, triggering an inflammatory response that damages the brain.

The first areas to be affected are those related to memory storage, including the hippocampus and entorhinal cortex in the temporal lobe.

In the new study, the researchers recruited 62 healthy adults over the age of 65. None of them had been diagnosed with dementia before the trial.

Researchers used a positron emission tomography (PET) scan to measure the amount of amyloid deposits in their brains; their sleep was then monitored with an electroencephalography (EEG) machine (which measures brainwave activity through tiny sensors attached to the scalp).

Brain waves change according to the different sleep stages – deep sleep is characterized by slow waves and lasts up to 40 minutes per sleep cycle (usually a person has four to six sleep cycles per night).

This is when the brain downloads and stores recent memories in a more permanent bank in the neocortex, which is part of the sheet of neural tissue that forms the outer wrinkled surface of the brain.

The PET scans showed that half of the participants had high amounts of amyloid deposits (the other half had no obvious disease), and of this group, those who experienced more deep sleep performed better on memory tests. Only the deep sleep phase of the sleep cycle was found to help preserve memory.

“One explanation is that during deep sleep specifically, memories are repeated in the brain – and this results in a neural reorganization that helps stabilize the memory and make it more permanent – a process we call memory consolidation,” says Dr Zavecz.

Another theory is that deep sleep supports “the brain’s ability to form new neural connections” and provides “an optimal brain state for the elimination of toxins that interfere with healthy brain function.”

Short daytime naps may have the same beneficial effect, she says, but adds, “This needs to be tested in further studies.”

One mystery is why some people with many signs of serious disease in the brain have almost no symptoms, while others with very few plaques and tangles have severe symptoms.

“If we believe that sleep is so crucial to memory, could sleep be one of those missing pieces in the explanatory puzzle that would tell us exactly why two people with the same amount of cruel, severe amyloid pathology have different memories?” suggests Matthew Walker, a professor of neuroscience and psychology at the University of California, Berkeley, and a senior author on the study.

“If the findings supported the hypothesis, it would be exciting, because sleep is something we can change.”

However, the study had its limitations, admits Dr Zavecz: ‘Our study has shown that sleep alters the effect of amyloid protein on memory function, but it does not prove causation.’

In other words, it could be something else that happens when we’re deep asleep that protects our memory.

So how can older adults get better quality deep sleep?

Dr. Zavecz advises, “Keep to a regular sleep schedule, stay mentally and physically active during the day, create a cool and dark sleep environment, and minimize things like coffee late in the day and screen time before bed.

“A hot shower before going to bed has also been shown to improve the quality of deep, slow sleep.” But sleeping pills probably won’t help.

‘In general, classic sleeping pills have not proven to be particularly helpful,’ says Professor Walker. “One proven method, however, is Cognitive Behavioral Therapy for Insomnia, or CBTi.”

This therapy helps people control negative thoughts and worries that interfere with their sleep and also teaches them better sleep habits.

“In addition, we and others have pioneered brain stimulation technology for promoting deep sleep,” he says.

This technique, called DC brain stimulation, sends a mild electrical current (that you don’t feel) into the brain. It’s already been shown to boost the size of brain waves in deep sleep – and it can also nearly double the amount of memory benefits you get from sleep, says Professor Walker from his study.

The question now is whether the same technology can be used to help the elderly and people with dementia. “The technique is still years away from clinical trials, but we’re getting there,” Professor Walker told Good Health.

Separately, researchers from the University of Surrey in the UK are investigating the role of good quality sleep in protecting memory in people already living with dementia. The university was awarded £1.7 million for further research into the sleep and circadian rhythms of people diagnosed with the condition.

Professor Derk-Jan Dijk, director of the Surrey Sleep Research Center at the university, explains: ‘People with dementia often have trouble sleeping and their memory often seems worse after a bad night.

“Good quality sleep is integral to our cognitive health, and now we need to test whether improving the sleep of people with dementia will slow the progression of the condition and preserve an individual’s memory for longer.”

Researchers will use digital monitoring equipment that can detect movement and physiological signals while the patients sleep.

Professor Dijk added: ‘A major advantage of the new digital technologies we are working with, many of which are contactless, is that they are low burden on the participant and can be used to monitor sleep and circadian. [body clock] rhythms in the home environment over weeks, months and years.’

The Surrey team will also continue to test new ways to improve sleep, including altering brain waves using auditory stimulation and improving lighting to help reset the body clock for better sleep.

Dr. Richard Oakley, associate director of research at the Alzheimer’s Society, said: ‘We know from our own research that 40 percent of dementia cases can be prevented by regular exercise, eating a healthy, balanced diet, not smoking and keep eating. blood pressure under control.

‘This [new U.S.] study showed how important sleep is for preserving a person’s memory when there are signs of Alzheimer’s disease in the brain.

‘While people in the study with higher levels of the rogue protein amyloid – linked to Alzheimer’s disease – had better memory after a night of deep sleep, we can’t say for sure that one caused the other. This needs to be explored in further studies,” he adds.

For more information about Alzheimer’s, visit www.alzheimer.nl alzheimers.org.ukwhere there is also an interactive symptom checklist.