There is a link between REM Sleep Disorders and neurodegenerative diseases.
In neurodegenerative diseases, we find a whole series of conditions which cause the neurons of the central nervous system to stop functioning or gradually die. This is the reason why the different neurological signs and symptoms appear.
These diseases tend to worsen over time and unfortunately have no cure. They can have a genetic origin or be caused by a tumor or a stroke. They also have a greater incidence in people who ingest large amounts of alcohol or who are exposed to certain viruses or toxins.
Sleep disorders can also have an influence on neurodegenerative diseases. A study by researchers at the University of Toronto, Canada, tells us that REM sleep disorders (or REM – Rapid Eye Movement) could be an early warning signal for neurological disease. Let’s dig deeper into this idea.
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REM Sleep or REM
Since the 1960s, scientists have claimed that dreams occur during the REM phase. The brainstem, it would be a key region in the control of these. It sits at the base of the brain and communicates with the hypothalamus to switch from wakefulness to sleep and vice versa.
A chain reaction is therefore triggered by the glutamatergic neurons SubC. These neurons regulate the transition from REM sleep to non-REM sleep. Their name comes from the area of the brain where they are found: the nucleus subcœruleus or SubC. This reaction results in the release of the neurotransmitter GABA which in turn lowers the level of arousal in the hypothalamus and brainstem.
This neurotransmitter is produced by GABAergic neurons. These are responsible for controlling the time of onset of REM sleep, its effects and, more specifically, the muscle paralysis that occurs during deep sleep.
When these cells activate, a rapid transition to REM sleep takes place. The brainstem sends signals to relax the muscles and stop moving the extremities.
With this in mind, the researchers decided to take a deep look at REM sleep disorders. Among the latter, we can highlight cataplexy, narcolepsy and REM sleep behavior disorder.
REM Sleep Disorders
People with REM sleep disorder wiggle their extremities or even stand up to perform a specific wakefulness activity while they sleep. Some may even shout or speak.
This disorder is considered a pathology when it endangers the person sleeping or those around him. The negative consequences of the problem sometimes alert about the diagnosis. This could be the case with self-inflicted or inflicted injuries on your partner while sleeping.
The good news is that REM sleep disorder can usually be treated successfully.
The Phases of Sleep
What we call “sleep” involves transitions between three different states: wakefulness, REM sleep, and N-REM sleep. There are a variety of characteristics that define each state. However, to understand sleep behavior disorder, it is important to know what happens during sleep.
In this state, the electrical activity of the brain resembles the electrical activity observed during wakefulness. Although neurons during REM sleep work almost the same as they do during wakefulness, REM sleep is nonetheless characterized by temporary muscle paralysis.
In some sleep disorders, such as narcolepsy, parasomnias, or REM sleep behavior disorder, the distinctions between these different states become more blurred. The neurological “barriers” that separate these states are believed to be malfunctioning. The cause of these phenomena is not yet well known.
Thus, the majority of people, even when dreaming, are unable to move their body. However, people with REM sleep disorder do not experience this muscle paralysis. This allows them to “experience” dramatic or violent dreams during the REM stage of sleep.
By examining the faults in the brain circuits that cause these sleep disturbances, the researchers made an interesting discovery. REM sleep disorders are linked to several neurodegenerative diseases that tend to appear in old age.
The researchers explain that, according to these findings, neurodegenerative processes affect the circuits that control REM sleep and, more specifically, SubC neurons.
They also observed that more than 80% of people who suffer from REM sleep disorders eventually develop synucleinopathies. These synucleinopathies include Parkinson’s disease and Lewy body dementia.
Sleep disturbances can therefore be an early warning signal for neurodegenerative diseases. These could appear about 15 years later.
It should be noted that Parkinson’s disease, like Lewy body dementia, is characterized by the intraneuronal build-up of a protein called alpha-synuclein. The researchers therefore hope that the study of this protein will open a path for neuroprotective therapies that would prevent the development of neurodegenerative diseases.
Scientists say that, like people prone to cancer, diagnosing REM sleep disorders can open the door to preventative actions to maintain good neural health, long before more serious neurological conditions emerge.