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Sleepwalking – unveiling the nocturnal mystery

Sleepwalking – though thoroughly studied – has always been a mystery to science. But new findings are bringing a little light into its darkness. Will these findings finally reveal the secret behind sleepwalking? 

It is amazing how much we rely on our brain, yet how little we know about it. In its normal function, it’s already hard to comprehend, so imagine how much more challenging it is to study when the person it belongs to is sleepwalking. But for a mysterious phenomenon, sleepwalking – or noctambulism as science calls it – is actually quite common: Around 30% of people sleepwalk at some point during their childhood (which is when people sleepwalk the most). Grown-ups on the other hand, sleepwalk less frequently.

The definition of a sleepwalking person is someone who leaves their bed at night and acts out of their senses. However, even though seemingly asleep, the sleepwalking person can execute complex behaviours such as driving a car. This extremely peculiar behaviour has inspired filmmakers, musicians, and other artists who continue to fantasize about this in their work. You might have seen this in movies where a sleepwalking person wanders around, looking like a terrifying zombie-like creature trying to spook people.  

No memory of the nocturnal excursions

But what makes sleepwalking even more strange is that the next day, we can’t seem to recollect the previous nightly trip. So let’s say you are sleepwalking and for some reason, your sleepwalking self feels like going for a ride in your grandmother’s car. The next day, your grandmother asks you slightly confused why you were standing in her driveway at 2 o’clock at night. Astonishingy, her story doesn’t ring the slightest bell and evokes nothing more than blankness in your memory.

So why is there relatively little known about noctambulism if it is actually quite common? The main reason is that the examination of it is rather tricky. Even though sleep laboratories are trying to observe people during their sleepwalking, the problem is that this always represents an interference in their normal sleeping behaviour. After all, the studied subjects are connected to various wires, which makes them act different to their normal sleeping behaviour in their own bed and familiar environment. For example, being attached to numerous wires could hinder participants to get up and sleepwalk, which would then deprive scientists of valuable test results. 

Current state of science

But what scientists in sleep laboratories did discover is this: While sleepwalking, the studied subject’s brain showed the same patterns as during the deep sleep phase. Since the deep sleep phase usually occurs during the first half of the night, most of the sleepwalking also happened in that first half.

However, while the majority of the brain showed the same patterns as during deep sleeping, there were some cognitive parts that were highly active. These active parts are the ones responsible for movement and muscle tension. This activity in certain brain parts is a necessary requirement for the nocturnal walking activity.

A painfree night’s rest

A new study published in the journal Sleep, adds another interesting chapter to the knowledge about sleepwalking. In the study, conducted in Montpellier, France, the question on how the experience of pain changes during sleepwalking, was analyzed. For this purpose, 100 people who stated to be regular sleepwalkers, were examined. 47 of them said they had gotten injured during their nightly walks before.

The scientists wanted to know whether these injuries had lead to the subjects waking up or whether they had continued to sleepwalk despite the pain caused by the injury. Out of those 47, only 10 said that they woke up from the pain. It is important to mention that those were not only minor injuries (like bumping into something) but also serious ones. For example, one person said that they fell out of a window from the third floor of a building. However, the person only felt the pain from the fall when they woke up later that night.  

Painfree nights, headache during daytime

Aside from this obviously dangerous resistance to pain during sleepwalking, scientists also noticed another curiosity. People who sleepwalk suffer ten times more often from headaches and four times more often from migraines than the average population. The nocturnal resistance to pain thus comes at a high price. So far, scientists were not able to find a reasonable explanation for the significant increase in symptoms of headaches and migraines. 

The questions that remain

Though these new findings add interesting facts to our knowledge about sleepwalking, they don’t fully uncover its mystery. For example the brainwaves that occur during sleepwalking, which are typical for the deep sleep phase, do not match the physical activity of sleepwalking, since the deep sleep phase is usually characterized by a kind of physical paralysis. Science will keep on studying what causes sleepwalking and its cognitive characteristics but until then, we might just have to rely on movies and other art forms to spark our fantasy about one of the most puzzling phenomena in the world. 

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1: Lopez, R., Jaussent, I. & Dauvilliers, Y. (2015) Pain in Sleepwalking: A Clinical Enigma. Sleep, 38(11), 1693-1698.

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