The Alzheimer’s disease is the most common form of dementia in France. Nearly one million French people are reached. As the population ages, this number could increase sharply in the coming years. To date, no drug targeting the cause of the disease is available. Treatments are only symptomatic. One of the objectives of current research is to prevent the onset of the disease or at least delay its onset. To do this, it is necessary to identify risk factors and implement actions to limit their impact. In this context, what is the place of sleep in the onset of Alzheimer’s disease?
Link between Alzheimer’s disease and sleep
From studies have already shown for some time that sleep problems are often present in patients, from the start of the pathology. The link between Alzheimer’s disease and sleep goes both ways. On the one hand, the cerebral lesions caused by the disease will degrade regions of the brain controlling sleep and therefore disrupting it. On the other hand, the sleeping troubles promote the occurrence of these same lesions. Indeed, lack of sleep in animals is associated with an increase in the amount of beta-amyloid peptide aggregates and tau protein in the brain, two biomarkers of the disease.
In this sense, poor quality sleep is therefore a risk factor to develop Alzheimer’s disease. A risk factor on which it is possible to act!
What sleep disorders?
To be able to act on the “sleep disorders” risk factor, it must be further characterized. Are these nights too short? Difficulties falling asleep? Of fragmented nights? A better understanding of the underlying mechanisms is essential before being able to define a strategy of prevention appropriate, and then deliver relevant public health messages. While it is still impossible to define with certainty which aspects of sleep are involved in the onset of Alzheimer’s disease, it is on the other hand clearly established by several Inserm studies that severe lack of sleep (less than 6 hours per night) is a risk factor for developing dementia.
So how do you improve your sleep? Work is underway to scientifically assess the impact of the activity physical or the meditation on the quality and duration people’s sleep. Regarding meditationthis is a promising track: it has already proof of its effectiveness on the slowing down of cerebral aging, the reduction of stress and anxiety. Enough to promote good sleep!
Alzheimer’s disease and sleep apnea: better understood mechanisms
Until now, scientists have sought to understand the biological mechanisms linking Alzheimer’s disease to poor quality sleep, which is known to have unquestionably deleterious effects on the brain. These alterations caused by sleep apnea have been revealed, by various cerebral imaging techniques, in the brains of healthy elderly people.
Inserm article, published on March 25, 2020
the syndrome Obstructive sleep apnea is the most common sleep breathing disorder, affecting more than 30% of the population after the age of 65. In subjects who are affected, this pathology results in uncontrolled and repeated interruptions of breathing during sleep, linked to the temporary obstruction of the upper airways, at the level of the throat. Sleep apnea is associated with many health problems, foremost among which are cardiovascular illnesses. However, this pathology remains silent for quite a long time, so that it is probably underestimated in the general population.
In recent years, scientific data have also accumulated showing a link between the quality of sleep, and in particular the presence of sleep apnea, and the development of Alzheimer’s disease. However, the biological mechanisms underlying this association remain to be elucidated.
To see more clearly, Inserm researcher Géraldine Rauchs conducted a study in the laboratory Physiopathology and Imaging of neurological diseases (Inserm/University of Caen-Normandy) in collaboration with the laboratory Neuropsychology and imaging of human memory (Inserm/University of Caen-Normandy/École Pratique des Hautes Etudes – PSL). In these works, published on March 23 in the journal JAMA Neurology, the researchers used several brain imaging techniques to map brain changes in people with untreated sleep apnea, both structurally and molecularly, as well as functionally.
Noticeable changes observed in the brain
The researchers first recruited 127 participants over the age of 65. In good health, they had no cognitive problems. Using a portable device to record their sleep and breathing at home during the night, the researchers detected the presence of sleep apnea, of varying degrees of severity, in 75% of them. .
All participants also underwent a series of tests to assess their cognitive functioning, including memory and executive functions. They answered questionnaires concerning the perceptions they had of their cognitive functioning and the quality of their sleep. Several brain imaging exams were then carried out, in order to study their brains from all angles and identify possible changes that could be associated with the Alzheimer’s disease. While no differences between the participants were observed in terms of their cognitive performance, brain imaging revealed several notable changes in the brains of the participants. people suffering from sleep apnea.
There are effective solutions to treat sleep apnea
Indeed, in these participants, the accumulation of beta-amyloid protein in the brain is more marked. Characteristic of Alzheimer’s disease, this protein accumulates in the form of plaques which, depending on their distribution in the brain and their density, can lead to the appearance of clinical signs of the pathology. In addition, the researchers observed an increase in the mass of matter gray and glucose consumption, suggesting the presence of inflammatory processes in the brain.
The links between Alzheimer’s disease and quality of sleep better understood
” TO the time when the clinical tests aimed at testing treatments against Alzheimer’s disease are not yet successful, identification of risk and protective factors on which to act is of increasing interest to researchers. Thanks to the use of several brain imaging methods, this study allowed us to specify the mechanisms explaining the links between quality of sleep, risk of cognitive decline and Alzheimer’s disease, explains Geraldine Rauchs. This does not mean that these people will necessarily develop the disease, but they are at higher risk. In addition, there are effective solutions to treat sleep apnea. Detecting sleep disorders, in particular sleep apnea, and treating them would therefore be part of the means to promote successful aging ».
To continue this work, the researcher and her team will now focus on the impact of apnea treatment on the evolution of brain damage and will also analyze the differences between the brains of men and women suffering from sleep apnea.
A sleep cure against Alzheimer’s?
A new study links sleep to the formation of senile plaques, structures found in abundance in the brains of people with Alzheimer’s. These results could lead to therapies aimed at improving the quality of nights to limit the development of the disease.
Article by Agnès Roux, published on October 25, 2013
The Alzheimer’s disease is a form of dementia that is accompanied by a progressive decline in cognitive function. Those affected gradually lose the memory and have learning difficulties. They are no longer able to cope with daily life and generally need medical assistance. According to Inserm, 860,000 French people were affected by this pathology in 2010. This figure continues to increase and should reach two million in 2020.
The first description of the disease was made in 1906 by the German physician Alois Alzheimer who observed suspicious plaques in the brain of one of his deceased patients. These structures were later called senile plaquesor amyloids, because they arise from the accumulation of a protein, beta-amyloid, between the neurons. These clusters appear naturally with aging, but agglutinate in much greater quantities in patients withAlzheimer’s. The origin of this accelerated accumulation of beta-amyloids, however, remains mysterious and is the subject of much research.
Who sleeps well protects his brain
Researchers at Johns-Hopkins University in Baltimore have just made progress on this subject. By going through a body of information, they realized that people with Alzheimer’s generally slept less and less well than others. They then wondered about the link between the sleep and the development of senile plaques. They were right: their study, published in the journal Jama Neurologyconfirms this association.
For this study, the scientists selected 70 healthy candidates with an average age of 76 years. First, they asked them about their sleeping habits: timefalling asleepnumber of nocturnal awakenings, difficulty falling asleep, waking up early, etc. Using several medical imaging technologies, they then observed the distribution and quantity of amyloid plaques in their brain.
Sleep therapy?
By compiling these data, the authors showed a link between the accumulation of senile plaques, the duration and quality of nights. However, the number of awakenings nocturnal does not seem to influence the formation of these clusters in the brain. These results are in line with a recent study showing that the brain got rid of its rubbish and toxins has a debit high during sleep. These researchers had in particular shown that beta-amyloids were eliminated twice as quickly during sleep, in mice.
All of these results reinforce the idea that it is important to spare your sleep to maintain a good balance in life. And Alzheimer’s disease is not the only reason. Studies have also shown a link between a lack of sleep and other diseases such as diabetes, cardiovascular problems, obesity, depressive disorders and Parkinson disease. Sleep would also promote the production of myelin in the brain and may decrease the progression of multiple sclerosis. “We could develop therapies to improve sleep and reduce the risk of Alzheimer’s disease, and other pathologies associated with lack of sleep »concludes Adam Spira, lead author of the study.
Interested in what you just read?