Unwanted events around our sleep, or when parasomnias bother us

They know how to be discreet but often end up imposing themselves in our sleep. They are generally not dangerous for us, poor sleepers, but they cannot leave us indifferent (failing to let us sleep peacefully), we are discussing here the famous parasomnias . "Para" ("beside") and "Somnie" ("sleep") are one and the same and paradoxically do not remain "aside" at bedtime, as these sleep disorders can invite themselves into our nights without us realizing it or remembering it. These parasomnias are not very nice!

What is a parasomnia?

A parasomnia is a sleep disorder, just like insomnia or hypersomnia, for example, with the difference that a parasomnia involves abnormal motor or psychomotor behavior during sleep, or on the border between sleep and wakefulness. Perhaps this is not clear? Then let's take an example. Sleepwalking is the most perfect illustration of what we call an adverse event (understand "abnormal motor or psychomotor behavior") occurring during sleep: the person who is the victim makes movements, seems awake, sometimes moves around, while being unaware of what they are doing. This is what a parasomnia corresponds to and, as we will see shortly, there are several of them, with different characteristics.

A separate category within sleep disorders, the different parasomnias have in common that they are characterized by undesirable and therefore singular behavioral or psychological events, but also that they occur unconsciously for those who are subject to them (with the exception of nightmares). A parasomnia, whatever it may be, is the result of a dissociation between the waking and sleeping states of consciousness . Since we are talking about several parasomnias, you are probably wondering how many there are. So what are the different types of parasomnias and how do we distinguish them?

First of all, you should know that parasomnias are distinguished from each other based on the phase of sleep during which they occur . Parasomnias are classified into 3 main types:

• Deep slow-wave sleep parasomnias : sleepwalking , night terrors , confusional awakenings
• REM sleep parasomnias : recurrent nightmares , sleep paralysis , catathrenia , REM sleep behavior disorder (RBD)
• Slow and REM sleep parasomnias : sleep eating disorder , sexsomnia , parasomnia recovery syndrome , sleep enuresis

Deep slow-wave sleep parasomnias are the most "common" and tend to affect children more than adults. Their prevalence is estimated at 4 to 17% of children and 2 to 4% of adults ¹ .

The main causes of parasomnias are linked to external factors that disrupt the quality and duration of sleep, but also sometimes to a genetic factor ² . Here are some of the causes of parasomnias:

• stress, anxiety
• alcohol consumption, drug use
• emotional shock, fever
• lack of sleep, jet lag
• genetic factor
• intensive practice of competitive sport

Generally, parasomnias do not pose any real health risks, except, in some cases, sleepwalking. However, parasomnias can cause certain inconveniences in daily life and have physical and even moral repercussions on the people who are subject to them, as well as on those around them. Here are the main consequences of parasomnias:

• poor sleep quality
• risks of physical injury (to oneself and others)
• increased fatigue
• anxiety, shame
• sleep disturbance of those around them

Here's a quick overview of what parasomnias are and what characteristics they have in common. As you might expect, we've known better company to spend the night with! Now it's time to make a few stops so we can quickly introduce the main parasomnias. Are you still following our nighttime GPS route?

Sleepwalking: a walk without leaving your sleep bubble!

Are there any Latin speakers in the audience? Literally, somnambulism means "to walk around while sleeping," which in itself sums up this singular sleep disorder quite well. Indeed, an episode of somnambulism leads the individual to wander and perform various and varied actions (walking, cleaning objects, eating, etc.) while unconscious.

Sleepwalking is a state of dissociated wakefulness (or incomplete wakefulness): the sleepwalker exhibits motor activity while asleep, even if their eyes are open, and will not remember their actions upon waking. Sleepwalking episodes can last from 5 to 30 minutes, sometimes less, and sometimes consist of a simple action (scanning, sitting in bed, touching objects, walking) or more complex and dangerous actions such as:

• go down stairs, open a door
• access cupboards, fridge or other storage spaces
• eat, drink, cook
• manipulate objects
• leave home, drive

The estimated prevalence of sleepwalking ³ is 2% for adults, but children are more affected by this parasomnia since more than 5% of them are subject to episodes of sleepwalking.

If you want to know more about this unconscious, and ultimately relaxing, nighttime stroll (yes, we walk while we sleep!), it's happening here!

Night terrors

Their name doesn't exactly inspire enthusiasm, we agree. And for good reason. Night terrors are a parasomnia of deep slow-wave sleep, meaning they occur at the beginning of the night, during the first 3 hours of sleep. They are similar to sleepwalking in that they occur at the beginning of the night, but also in the physical manifestations they cause.

Indeed, during an episode of night terror , the individual manifests typical elements of fear, such as screaming, sweating, very agitated gestures or panting. This can be very "spectacular" and worrying, especially for parents, but it remains without particular danger. This phenomenon mainly affects children,almost 5% of them ⁴ , and mainly between 3 and 6 years old.

Just like sleepwalking, a child who experiences night terrors has no memory of them once they wake up, and that's probably not a bad thing, right? For scholars who would like to know more about night terrors, click here!

Nightmares: Movies throughout the night!

This is one of the most well-known and popular sleep disorders. Popular, not because we love it, but rather in the sense that it affects a large number of people, to varying degrees. Nightmares occur at the end of the sleep cycle, during the REM sleep phase. We could say that nightmares "play themselves out," as events worthy of the best Hollywood movies can unfold in some of them!

A nightmare is actually our brain's response to the stress and difficulties we experience on a daily basis. They have a regulatory and cathartic function to help us face our fears! It is therefore completely normal to have nightmares. The prevalence of so-called "recurrent" nightmares , i.e. at least once a week, is estimated at 5% of the general population ⁵ .

However, when nightmares occur daily, they become pathological and can be symptomatic of a psychological disorder. Unlike night terrors or sleepwalking, it is quite common to remember nightmares upon waking.

For those who would like to know what is really behind nightmares, and what their real meaning is, go right here to discover the behind the scenes of the film “Why do we have nightmares”.

Other parasomnias

Here, in a few words, is a brief presentation of other parasomnias, the latter being generally relatively less widespread:

• sleep paralysis : this is a sleep disorder, a symptom of narcolepsy, during which one is unable to move while conscious, sometimes for several minutes, and which may be accompanied by hallucinations
• Catathrenia : This is a benign sleep disorder characterized by the production of noises during sleep, such as grunts or moans, which can last for several minutes or even be repeated several times during the night.
• confusional awakenings : this sleep disorder is common in young children, less so in adults (around 4% of the population), and is characterized by disorientation of the individual upon waking, with a loss of temporal and spatial references, as well as behavioral inconsistencies, all of which can last around ten minutes
• sleep eating disorder : this relatively rare sleep eating parasomnia consists of a neurophysiological disorder, similar to sleepwalking, which leads the individual to eat during their sleep, unconsciously!
• Sexsomnia : This is a parasomnia related to sleepwalking in which the person suffering from it unconsciously engages in sexual behavior, which can lead to involuntary sexual acts towards a spouse or other people in the entourage.

Parasomnias are therefore undesirable and most often unconscious events, as we have seen, and which we would gladly do without to fuel our nights! However, most of them are not dangerous and, fortunately, the subject suffering from a parasomnia almost never remembers them. It is the close entourage who can unfortunately suffer from it, to a certain extent.

It is true, however, that psychological and moral suffering can set in for some people who are victims of parasomnia. Indeed, a feeling of guilt and/or frustration, even unjustified, can lead an individual to blame themselves for their “undesirable behaviors” caused by their sleep disorder as well as for the repercussions caused on those around them, or on themselves, although this is beyond their control...

Sources:

[1] Night terrors, sleepwalking, and confusional arousals in the general population: their frequency and relationship to other sleep and mental disorders , MM Ohayon, C Guilleminault et al, “The Journal of Clinical Psychiatry”, April 1999 [2] Prevalence and genetics of sleepwalking: a population-based twin study , C Hublin, J Kaprio et al, “Neurology”, January 1997 [3] Prevalence of Sleepwalking: A Systematic Review and Meta-Analysis , Mark Kohler, “Plos One”, November 2016 [4]Sleepwalking, nightmares and night terrors in children , “Fondation Sommeil” website, 2020 [5] Prevalence and Correlates of Frequent Nightmares: A Community-Based 2-Phase Study , Shirley Xin Li, Bin Zhang et al, “Sleep”, June 2010