Night terror, or the nightmare of parents for their children

A "night terror", this could have made a striking title for a B-movie, in other words, a film intended to scare or distress. Despite our strong taste for the 7th art, we will here focus on night terrors as a parasomnia and, once is not customary, this sleep disorder concerns almost exclusively children under 18 years old. Like horror movies, which are also prohibited for those under 18? It's a bit like that, indeed, except that children are not aiming for an Oscar for their performance!

More seriously, night terrors, in their manifestations, can reveal themselves to be a distressing, sometimes frightening scene, and the helplessness of parents in the face of this scene is all the more frustrating. What do we really know about night terrors? While we know they can be spectacular, are they dangerous? Is there a difference between nightmares and night terrors? These are indeed questions that the relatives of those suffering from this spectacular and particular sleep disorder should ask themselves, and rightly so. Don't panic, let our chief sleep director guide you to better understand night terrors, and thus better manage them if you ever encounter them!

What is a night terror?

It is a sleep disorder classified under deep slow sleep parasomnias (undesirable events, abnormal behaviors occurring during sleep) and most often occurs in children, between 3 and 6 years old. However, a small percentage of adults, around 2.2%¹, may encounter this phenomenon. The origins of night terrors in adults may differ from those in children. A neurological disorder², for example, could be one of the causes behind this parasomnia in adults, although this theory requires further investigation.

Night terrors occur during the first 3 hours of sleep. They actually correspond to a problem of transition between the deep sleep phase and the REM sleep phase (dreams, nightmares). It should be noted that during this phase of deep slow sleep, night terrors can be accompanied by another parasomnia of the same type, sleepwalking. The prevalence of this 'association' is not yet clearly established, but a recent study³ has looked into the subject. To be continued!

During a night terror, the child becomes agitated, displaying characteristic elements of fear such as screams, sweating, or even gasping for breath. While this spectacular phenomenon can be traumatic for parents or anyone witnessing it, children do not retain any memory of it, and this is where night terrors differ from nightmares. One can remember a beautiful dream or an unpleasant nightmare, but one does not remember having been a victim of a night terror, which is rather a good thing, you will agree!

Night terrors are therefore synonymous with the beginning of a difficult and restless night, but the person suffering from it is not aware and is still asleep, even if their eyes are open. This disruption of the sleep cycle stops on its own and usually lasts from 2 to 20 minutes at most, just the time for a somewhat agitated little scene.

Night terrors in numbers

As mentioned earlier, night terrors primarily affect young children. While the figures may somewhat diverge depending on age groups, it can still be estimated that 5% of children are subject to night terrors⁴.

A recent study evaluates the prevalence of night terrors " between 1 and 6.5%⁵ " among children aged 1 to 12 years. While the figures may vary depending on studies on general prevalence, they mostly agree that the "peak" of night terror activity occurs between the ages of 4 and 7, and that this phenomenon affects nearly 40% of children under 6 years old⁶.

It can therefore be observed, in light of these figures, that night terrors primarily occur between the ages of 4 and 7, and then significantly decrease from the age of 12, once sleep cycles are well established. However, as we mentioned earlier, a very small minority of adults, just over 2%, may face this phenomenon during their lifetime. After all, a little parental solidarity is needed in this area too!

What are the causes of night terrors?

First of all, it is important to differentiating nightmares and night terrors. Here is a brief reminder of the main characteristics of a nightmare:

• it occurs during REM sleep, that is to say at the end of the night
• one can remember it upon waking
• it can be caused by traumatic events, by stress, or in response to drug withdrawal

Regarding night terrors, their occurrence at the beginning of the night results from a "failed" transition between slow sleep and REM sleep. Although they are similar to sleepwalking and nightmares, which are also considered parasomnias, night terrors have their own causes.

Indeed, many studies have shed light on a set of probable causes of night terrors. According to specialized organizations in the study of sleep, such as " Sleep Foundation⁷ ", and referencing a recent study⁸, we can consider that the main causes of night terrors are as follows:

• lack of sleep (stopping naps for 4-6 year olds in particular)
• fatigue
• irregular sleep hours and rhythms
• fever
• sleep apnea
• intense physical activity
• taking medication
• noisy environment, too bright light

If, for younger children, lack of sleep remains the main cause of night terrors, it is also possible to consider stress (or any traumatic event) when these disturbances persist beyond the age of 6. Indeed, at this age, it is estimated that sleep cycles are well established, and the biological clock ('circadian rhythm') should be set.

Moreover, some studies report a genetic factor that favors the predisposition to night terrors (as well as for sleepwalking). One of them⁹ reports that 96% of people prone to night terrors have a family member who has faced one or the other of these parasomnias (this figure is 80% for sleepwalking). In other words, a little family survey can be very useful in preparing for the possibility of restless nights and spectacular scenes with your child!

How do night terrors manifest?

You wonder how to recognize a night terror? For this parasomnia, the symptoms are quite easily identifiable and are very characteristic of the phenomenon. As the saying goes, 'you know who you are dealing with' when this sleep disorder manifests. Here are the symptoms of a night terror:

• the child (or adult) sits down
• manifestations of screams, cries (the famous 'Hitchcockian' scream!)
• despite the state of unconsciousness, the eyes are open (in 'mydriasis')
• appearance of sweat (hypersudation)
• accelerated breathing (tachycardia)
• the skin tone becomes redder (erythrosis)
• pronunciation of incomprehensible or incoherent words
• agitation, movement of defense or to struggle

You will understand, the manifestations of a night terror can distress, even shock the "spectators". The first phase is quite brutal: the child sits up, their eyes open, and there, we witness a real scene of crying and fear, accompanied by screams. This is followed by spectacular agitation, all at the breathless pace of frantic breathing, the child struggles with great vigor. Out of breath, this episode stops abruptly, sometimes after a few minutes, without the child remembering anything. The night of sleep then continues, the child falls back asleep, even if they were not awake, as they are unconscious, and they return to the land of dreams.

If the privilege of remembering the scene belongs to the parent, the child, on the other hand, suffers no aftereffects and retains no trace of this night terror in their memory, and that is the main thing!

Diagnosis and treatment of night terrors

This is a differential diagnosis, meaning that we seek to eliminate other parasomnias or pathologies that may cause the same symptoms.

Thus, characterizing and diagnosing a night terror is quite simple. Indeed, only nightmares and hypnagogic hallucinations (related to sleep paralysis) provoke a set of similar symptoms. As highlighted by Dr. Marie-Josèphe Challamel¹⁰, pediatrician at the "Centre du Sommeil de Lyon" and research officer at "INSERM", "in both cases, the child is fully conscious and awake", which allows for the differentiation of night terrors from nightmares (which, moreover, occur later in the sleep cycle), but also from hypnagogic hallucinations. Differential diagnosis with other pathologies such as sleepwalking, narcolepsy, or others can be performed through a medical consultation, particularly thanks to polysomnography or an examination in a sleep center.

Here too, regarding treatment, it is quite easy to identify given... that it does not exist! More precisely, doctors agree that night terrors are not abnormal, they correspond to a form of maturation of sleep cycles. As a result, treatment is actually more about support during the manifestation of this disorder, ensuring a safe environment (furniture or objects), especially to avoid any potential injury during agitation and excess uncontrolled movements. Attempts to reassure the child are, alas, in vain and useless, as the child is not in a conscious state.

However, and even if this could help parents get through this crisis by feeling more useful, it is preferable not to intervene (either verbally or physically), at the risk of prolonging the episode or amplifying the child's defensive movements. It should be kept in mind that a night terror is, fundamentally, perfectly normal at the childhood stage!

If there is no standard treatment for night terrors, it is still possible to limit known aggravating factors. In doing so, it is possible to follow these few recommendations:

• establishing naps during the day
• scheduled awakening¹¹: after observing and noting the usual delay between falling asleep and the night terror, one can schedule the child's awakening¹² 10-15 minutes beforehand to avoid the episode, then let them fall back asleep after 5 minutes
• practice 'cosleeping¹³': a new medical approach that involves creating a secure environment for the child to limit stress during periods prone to night terrors
• adopt a suitable lifestyle and sleep hygiene (regular bedtime, diet, avoid intense physical activity during the day...)

The use of medication is generally prohibited for treating night terrors, as side effects, especially in children, can be dangerous. However, in rare cases and for a very short duration, 'benzodiazepines' may be prescribed to relieve acute and very frequent episodes, which can be too distressing in the long term.

For adults continuing to suffer from night terrors, treatments, also of short duration, can be considered:

• paroxetine (antidepressant)
• melatonin
• carbamazepine

Night terrors are just as distressing for the 'spectator' parents as they are not dangerous for the children, provided that a risk-free environment is ensured and the signs of agitation are monitored to prevent minor injuries. The film of life sometimes unfolds with spectacularly agitated and noisy surprises, thus bringing the necessary spice to the appreciation of its resolution. Night terrors are therefore sometimes part of the script, contributing to the establishment of the internal clock and circadian rhythm in our beloved little ones. We must cope with this mischievous sleep disorder... for a few episodes!

To complete and illustrate the content of this article, here is a little bonus video, just for you:

an explanation about parasomnias, by Joëlle Adrien, neurobiologist and research director at INSERM

Sources:

[1] Parasomnias of deep slow sleep, Dr N. Limousin, site « Collège des enseignants de neurologie », 2020 [2] Night Terrors, « StatPearls », July 2020 [3] Sleepwalking and Sleep terrors, site « Harvard Health Publishing », February 2020 [4] Sleepwalking, nightmares, and night terrors in children, site « Fondation Sommeil », 2020 [5], [8] and [12] Sleep terrors: an updated review, Alexander K C Leung 1, Amy A M Leung et al, « Current Pediatric Reviews », October 2019 [6] The different types of sleep disorders in children, site « Ameli.fr », April 2020 [7] Night Terrors: when to talk with a doctor, site « Sleep Foundation », July 2020 [9] Hereditary factors in sleepwalking and night terrors, A. Kales, C. R. Soldatos et al, « The British Journal of Psychiatry », August 1980 [10] Children's parasomnias, Dr Marie Josèphe Challamel, site « Université Lyon 1 », 2020 [11] Night Terrors, Ngoc L. Van Horn, Megan Street, « StatPearls », July 2020 [13] An evolutionary perspective on night terrors, Sean D Boyden, Martha Pott et al, « Evolution, Medicine and Public Health », April 2018