Let's imagine for a moment we're walking together
down the streets of a British town in the early part of the 19th century.
It's almost dawn, and the gas street lamps form yellow globes of light in the early morning mist.
Ahead, we see a figure begin to emerge from the haze. It appears to be human but from its
body extends a long thin appendage that reaches high into the gloom.
Is it an alien? And is that an antenna in its pocket or is it just pleased to see us?
No, it's a man, and as he moves closer we see he's carrying a long bamboo cane that he uses to tap on
the upper floor window of each house he passes. He's a knocker-up, also known as a knocker-upper,
someone hired to wake people in the morning to ensure they get to work on time. Not to be
confused with the other type of knocker-upper who does his job once and gets paid nine months later.
Starting in the industrial era, in the times before reliable and cost-effective alarm clocks,
knocker-ups were the people who got you out of bed in the morning.
Charles Dickens made reference to knocking up in his novel Great Expectations, which makes sense,
because life in Victorian England was pretty shit for most people. It's no
surprise they needed a little extra motivation to get the day started.
Times have changed, but most of us still find it hard to get going in the morning.
If you really struggle to get out of bed each day, you may even have a condition
called dysania, which, although not yet medically recognised, is a near complete inability to get
out of bed in the morning that’s thought to be linked to other conditions like depression and
chronic fatigue syndrome. And if you have an overwhelming desire to stay in bed all day,
you might have a closely-related condition called clinomania.
Or you might just be horribly hungover.
Regardless, waking up overly tired is usually a sign that something’s wrong
or you're not getting enough proper sleep, which could simply be due to your lifestyle,
or perhaps one of approximately 80 different sleep disorders.
For example, if someone wakes you while you’re in a deep sleep, you'll probably feel a bit
lost and disorientated. If this response is particularly intense or occurs regularly,
you may be experiencing confusional arousals, not to be mixed up with inappropriate arousal,
which is a terrible affliction experienced by teenage boys at least three times a day.
Confusional arousal is a condition in which you act in a very strange or confused way
when you wake up. Episodes may involve inappropriate behaviour,
shouting, or an apparent inability to "wake up". Sounds like me on any normal day.
Other sleep disorders are even more bizarre. Have you ever suffered from
Exploding Head Syndrome? Although it sounds like a scene from a Quentin Tarantino film,
it actually isn't quite as dramatic as you might think.
Sufferers of this condition hear a sudden and incredibly loud noise - like a gunshot
or a door slamming - just as they're drifting off to sleep, or as they wake up from a deep sleep,
even though the room is completely silent
Every night you move through several sleep cycles, with each cycle having five stages:
four stages of non-rapid eye movement or non-REM sleep, and one stage of REM sleep. It is during
REM sleep that you experience dreams, and to stop you acting out those fantasies in the real world,
your brain temporarily paralyses your body - a process called atonia.
Sleep paralysis happens when you gain consciousness before your body has moved
fully out of the rapid eye movement or REM stage of sleep,
and if you’ve ever experienced it you’ll know it can be absolutely terrifying. In this state,
you’re semi-awake or even fully-awake, but completely unable to move a muscle.
And as if total immobility weren’t enough,
there are even stranger symptoms of this surprisingly common condition.
As many as 40% of people experience sleep paralysis at some point in their lives, and many
recall sensing a presence nearby or even on top of them during the period of paralysis, causing
a feeling of intense pressure on their chest and an inability to breathe. That presence has taken
many forms, usually shaped by the cultural beliefs of the time. Characters have ranged from witches
to trolls to ghosts, with aliens being the most popular nighttime chest-sitters in the modern era.
The condition is believed to be the origin of the incubus and succubus myths, which warn of demons
that attack during the night, usually sexually. Sleep paralysis is also thought to have been
the inspiration for the famous 18th-century painting by Henry Fuseli - no relation to the
pasta - called ''The Nightmare,'' which shows a goblin sitting on the stomach of a sleeping woman.
Confusional arousals, exploding head syndrome and sleep paralysis are all examples of parasomnias,
a broad group of sleep disorders that involve weird things happening while
you’re falling asleep, sleeping or waking up.
They can include strange dreams, emotions, movements, or behaviours,
and most of them happen during non-REM sleep. They can sometimes be traumatic for the person
involved or the people they live with, but for the most part, these conditions are fairly harmless.
Take sleep-talking, for instance. Sure, you may say a few embarrassing things out loud
while asleep on the train, but seriously, if you like rubbing peanut butter on your nipples
you shouldn’t be embarrased to tell the world about it while unconscious.
Or how about sleep sex, also known as sexsomnia?
Nothing wrong with wanting to get your jollies off mid-slumber is there?
Then there’s sleepwalking. Everyone knows somebody with a funny sleepwalking story. But surely,
apart from the risk of walking into things, peeing in your cupboard or falling down stairs,
it's all just a bit of fun?
Well, yes, most manifestations of parasomnias have little impact in the wider world. But in some
alarming cases, they have ended in violent, even fatal, criminal acts being committed
under the supposed blanket of sleep.
The defendants in these cases have sworn they were asleep when committing their crimes and knew
nothing of their actions, an argument that has come to be known as the 'sleepwalking defence.'
Sleepwalking, technically known as somnambulism, usually occurs during slow-wave sleep,
the deepest stages of non-REM sleep. Exactly what causes it isn’t known, but essentially
the brain seems to get stuck between sleep and wakefulness.
Recently, some researchers have provided an alternative theory that, instead of being awake or
asleep, sleepwalkers are both at the same time in what might be a new type of state disassociation,
with consciousness and unconsciousness switching rapidly and continuously.
Either way, sleepwalkers can do a lot more than walk. They may sit up and look around,
pick up objects around the home, take a stroll out of the house or even drive.
There’s a common myth that you shouldn't wake a sleepwalker, when in fact leaving someone to
sleepwalk can lead to disastrous, even homicidal, consequences, as we’re about to find out.
The first legal record of sleepwalking being used as a successful defence
was in the United States in 1846. In what became known as The Boston Tragedy,
Albert Tirrell slit the throat of the woman he’d left his wife for, a prostitute named Maria
Bickford, almost decapitating her in the process. Then, just to prove he meant business, he set fire
to the brothel and fled to New Orleans, where he was arrested. In court, his lawyer argued that
Tirrell was a longtime and chronic sleepwalker and perhaps committed the crime while asleep.
And the jury obviously thought it was a plausible story, because Tirrell was acquitted.
In 1887,esteemed Paris detective Robert Ledru was sent to Normandy to help solve an ongoing case.
He arrived at night and went to bed early, but woke the next morning to find his shoes and socks
were soaked through. He also discovered the case he’d been assigned to
was no longer a priority because, during the night, there had been a murdah – a murdah?
Aye, a murdah. A prominent businessman had been shot on the beach, with no clues as to
why. Ledru investigated, taking plaster casts of the footprints that led to the corpse.
He was naturally more than a little surprised to discover the footprints exactly matched his own,
and combined with his inexplicably wet socks and shoes, he came to the startling conclusion he
was the murderer, despite having no recollection whatsoever of the crime.
His findings were confirmed by ballistics testing, and he was imprisoned for his own
good. During his incarceration, prison guards gave him a gun loaded with blanks, and one night,
Ledru suddenly got up and started firing at the man guarding his cell. It was enough to
convince the authorities that he was a homicidal sleepwalker, and not a cold blooded killer. Ledru
was moved to a secluded farm outside Paris and kept there until his death 50 years later.
Perhaps the most well-known of these cases occurred in 1987 when Kenneth Parks,
a young Canadian man, was acquitted of murder on the grounds of sleepwalking. One night
Parks climbed into his car and drove 14 miles to his parents-in-law’s house
where he proceeded to strangle, beat and stab his mother and father-in-law, with whom he apparently
had close relationships. His mother-in-law was killed, and his father-in-law seriously injured.
Afterwards, still dripping with blood, Parks drove to a police station and confessed to the crimes,
but witnesses said he appeared confused about what had happened.
He had also severed tendons in both hands during the attack and should have been feeling intense
pain, but he seemed altogether unaware of his injuries. At the trial, the jury was
convinced Parks had indeed been unconscious at the time, and he was found not guilty.
More recently, in 2008, British man Brian Thomas was accused of the murder of his wife,
who he admitted he’d strangled in the back of their campervan. Thomas couldn't remember what had
happened but thought he had been dreaming that his wife was an intruder. The prosecution eventually
withdrew the charges, and the judge said that Thomas wasn't responsible for his actions.
But before you start planning to bump off that annoying guy at work who always steals
your parking space before giving an exaggerated yawn and claiming you were asleep the whole time,
it’s worth bearing in mind not everyone gets away with the sleepwalking defence.
In 1997 in Phoenix, Arizona, Scott Falater stabbed his wife 44 times with a hunting knife.
His neighbour also testified to seeing him drag his wife's body to the pool
before holding her head underwater. Falater claimed to have been asleep at the time,
saying he had a history of sleepwalking and had been sleep-deprived in the run up to the incident.
The prosecution argued Falater had tried to hide evidence of the murder in a way that was
too complex to have been achieved while asleep. And in between the stabbing and the drowning,
a neighbour also saw Falater motion for his dog to lie down, which was considered
a possible sign of consciousness. A jury found him guilty of first-degree murder in 1999.
In Spain in 2001, Antonio Nieto brutally killed his wife and mother-in-law. His
daughter and son tried to stop him, and both received severe injuries for their efforts.
Nieto told the court he had been asleep during the attack and had been dreaming he was defending
himself against aggressive ostriches. Full marks for inventiveness there Antonio.
But his children said he had recognised them during the attack and had even told them not
to turn the light on because their mother, who had already been brutally assaulted,
was supposedly sleeping. Nieto was sentenced to 10 years in a psychiatric facility.
These are only a few of more than 100 examples of apparent sleep-related violence that have
been reported in the last century or so, which include instances of homicide, assault,
and sexual assault. For a long time, doctors and lawyers lumped all types of bizarre sleep violence
under the heading of sleepwalking, but there are distinct differences between somnambulism
and another type of parasomnia: REM behaviour disorder, or RBD.
REM behaviour disorder happens during REM sleep while someone is dreaming
but, instead of the muscles being paralysed as usual,
the dreamer's body is still active and they're able to act out their dreams.
When they’re woken up, they can usually remember fragments of the dream they were in.
This is different from sleepwalkers who, operating from non-REM sleep, usually have no recollection
of what happened once they’re woken and are in general more confused and disorientated.
Somnambulism and RBD are quite different, but I for one wouldn’t be overly interested
in the semantics if someone in a nightgown was chasing me with an axe.
So why do these types of distinctions matter?
In the end, they help to determine the tricky business of truth.
Up until fairly recently, it was impossible to test whether someone
was telling the truth when they claimed to have been asleep during a violent episode.
Traditionally, courts have relied on historical and circumstantial evidence to make the call.
Sleepwalking, for example, is partly genetic,
and sufferers of RBD or somnambulism often have a history of the condition.
Sleep deprivation, stress, alcohol, and drugs can also make someone more susceptible to an episode.
Sleepwalking is also often triggered by a sound, heavy snoring being the most common. All of these
points have in the past been used as indicators as to whether a defendant is telling the truth.
But technological advancements have made it possible for scientists to make
accurate assessments about whether someone is a genuine sleepwalker or just a sleepliar.
Three lab tests are used to assess when someone is in different stages of sleep.
The first, an electroencephalogram (EEG), records brain activity in the form of waves. The second,
an electrooculogram (EOG), detects eye movements, and finally, an electromyogram
(EMG) measures muscle activity via a sensor placed on the chin, or an arm or leg.
Of course, the number of people who have committed a crime while asleep
and wearing these different sensors is pretty low - OK zero - so we don't have definitive proof of
whether a potential murderer was asleep or not when they acted violently. But, being able to
retrospectively assess people's sleep patterns can help to establish probability. Because
you know, if someone goes to sleep every night repeatedly slapping his penis as he drifts off,
he’s probably more partial to a spot of sleep murder than someone who sleeps like a log.
Neuroimaging studies have also started to advance our understanding of how sleepwalking works.
Claudio Bassetti of the University of Zurich has examined the brains of sleepwalkers
using single-photon emission computerised tomography, or SPECT.
He has discovered that, in sleepwalking states,
your brain's cerebrum and cerebral cortex - the clever parts of your brain that decide
the difference between right and wrong - shut down. Your brain becomes directed by
more primitive and automatic functions, the kind connected to hunger, sex, and survival.
From a legal point of view, it confirms that sleepwalkers and sufferers of RBD
are not conscious when they’re asleep and, so cannot be considered to have mens rea,
which is the intention to commit a crime and is typically required for someone to be found guilty.
We’re still some way off from having a foolproof way of deciding whether or not
someone was genuinely asleep when they committed some terrible act of violence,
but we do now know that this is a real thing. So, until we understand more, it might be an idea
to hide the kitchen knives before you switch the lights out each night. And, of course, sleep well.