Sleepwalking and sleep paralysis are two sleep disorders classified within the international classification of sleep disorders (ICSD-3) and belong to the group of parasomnias. Sleepwalking specifically belongs to the NREM sleep parasomnias and sleep paralysis to the REM sleep parasomnias.
What is sleepwalking?
Sleepwalking is a behavioral disturbance during the night that occurs in 5 to 10% of children under 15 years of age. In most cases, sleepwalking improves over the years, when adolescence is reached, although there are cases in which sleepwalking continues into adulthood.
Sleepwalking is a sleep disorder characterized by partial and unconscious awakening in NREM sleep. The essential characteristic of sleepwalking is the existence of repeated episodes of complex motor behaviors that are initiated during deep sleep.
The sleepwalker often does things or talks while asleep, such as rubbing the eyes, walking around the room, or even leaving the house.
In addition, a sleepwalker has the ability to avoid objects, but the mind and reasoning ability are greatly altered. It can be said that the person acts and talks, but is not aware of anything that is happening.
What is sleep paralysis?
Sleep paralysis is a muscular condition in which there is atony or slackness produced by the condition of being asleep in REM sleep. This slackness temporarily prevents you from making any muscle movements.
Sleep paralysis is when you try to wake up from bed and try to get out of bed and cannot. This phenomenon usually occurs when we are falling asleep or when we are waking up. The normal thing is not to be able to move the muscles nor to articulate word. The duration of this phenomenon is very short, it can last between one and five minutes. People suffering from this paralysis are usually very frightened and distressed even though they are perfectly awake and lucid. Although it is complicated, the ideal is to calm down and wait quietly until it passes naturally.
Why do some sleep disorders, such as sleepwalking or sleep paralysis, occur?
Factors that may contribute to sleepwalking episodes include:
- sleep deprivation
- stress
- fever
- interruptions in sleep schedule
- travel
- sleep interruptions
Sometimes sleepwalking can be caused by undiagnosed conditions that interfere with sleep, such as: obstructive sleep apnea, taking certain medications (such as hypnotics, sedatives and certain medications for psychiatric disorders), consumption of toxic substances such as alcohol and drugs, restless legs syndrome, gastroesophageal reflux disease, among others. In occasional cases it may be related to a tumor or brain injury.
The most common causes that can trigger episodes of sleep paralysis may be several:
- Living a strong episode of stress
- Being under a lot of pressure
- Sleeping badly many nights in a row
- Lack of sleep
- Accumulated sleep
In what phase of sleep does sleepwalking occur? What about sleep paralysis?
Both disorders are in the group of parasomnias, but sleepwalking is classified within the group of NREM parasomnias and sleep paralysis is classified within the group of REM parasomnias.
To understand it better, we will explain in a simple way the different stages of sleep.
Not all rest and sleep is the same once we get into bed. Sleep is divided into cycles of approximately 90 minutes that are repeated during the hours we sleep.
Within these cycles, there are different stages of two types of sleep: slow sleep and paradoxical sleep. Let’s look at the different stages classified as REM sleep and NREM sleep.
NREM sleep: During NREM sleep the following phases occur:
- Phase I or stage of dozing: comprises approximately the first 10 minutes of sleep. This is a transitional stage, from the time we are in the waking period until we fall asleep.
- Phase II or light sleep stage: occupies about 50% of our sleep cycles. Both breathing and heart rate slow down. During this phase is when people have the typical dream of falling off a cliff and waking up suddenly.
- Phase III or deep sleep stage: this stage occupies approximately 20% of the total sleep cycle. It is the most important in determining the quality of rest. It is very difficult to wake up. It is in this stage that the sleepwalker “wakes up”.
REM sleep or paradoxical sleep stage: It covers approximately 25% of the sleep cycle and lasts between 15 and 30 minutes. During this phase, we have a constant movement of the eyeballs under the eyelids.
It is characterized by high brain activity, very similar to when we are awake, although our muscles are blocked. It is the phase in which we dream and capture information from the outside and it is the phase in which, if we wake up, the episode of sleep paralysis can occur.
Could they be considered two opposite disorders, because sleepwalking allows us to get up and move, and paralysis prevents us from moving the body, even though the brain is already awake?
Yes, since, as we have discussed in greater depth in the previous section, sleepwalking occurs in NREM sleep and the person is not aware of the acts and movements he is performing, while sleep paralysis occurs in REM sleep and the person is fully aware of what is happening to him, but cannot perform any movement.
How does the brain act in each of these disorders and why, in the case of paralysis, does it not allow the body to move?
Sleepwalking occurs during NREM sleep, specifically in the N3 sleep phase, the deepest phase of synchronized sleep. If we wake up in this phase we can suffer a sleepwalking episode by performing automatic behaviors without remembering the episode.
Whereas sleep paralysis occurs when the body and mind are not well connected at a moment during REM sleep. In REM sleep we usually dream, while our body is completely paralyzed because the muscles are very relaxed resting. When our brain wakes up in the REM phase, before the end of sleep this paralysis occurs, because the muscles have not yet recovered from rest.
Is there any therapy or treatment for sleepwalking and sleep paralysis?
There are very effective treatments for both sleep disorders, but the main thing is to detect before any of the triggering factors and apply good sleep hygiene measures and in this way it is possible to solve more than 90% of these disorders without having to medicate. In extreme cases, treatment can be carried out with benzodiazepines or antidepressants to reduce or eliminate the number of episodes.
When should I consult a medical specialist?
Sporadic episodes of sleepwalking and sleep paralysis are not usually a cause for concern and usually resolve on their own. You may simply mention sleepwalking or sleep paralysis during a routine physical examination or checkup. However, you should consult a sleep medicine physician if episodes of sleepwalking or sleep paralysis present any of the following:
- They occur often, for example, more than once or twice a week or several times in one night.
- When it generates a lot of anxiety for the person who suffers from it.
- They cause daytime symptoms of excessive sleepiness or problems in accomplishing your tasks.
- Cause dangerous behaviors or injuries to the person with sleepwalking or to others
- Significantly disrupt the sleep of people in the household or the person who sleepwalks.
- Begin in adulthood
- Continue when your child is a teenager