The science of sleepwalking
Tasmanian David Kohler remembers well his first brush with sleepwalking. He was about 10 years old and was dreaming about climbing a sand dune like those near his home in Queenstown.
“Just as I neared the top and reached out for a metal bar that appeared from nowhere I woke with a thud to find myself sprawled in the dark below my bedroom window,” recalls Kohler, 35.
The three-metre fall caused more shock and confusion than injury but it marked his introduction to somnambulism, a condition the agricultural researcher now shares with his wife, their 13-year-old son and what recent research has found is a sizeable chunk of the population.
Sleepwalking is an arousal disorder – which usually occurs in the first third of sleep – where a person moves in a dreamlike state with the ability to perform familiar tasks such as dressing, opening doors and windows and, in extreme cases, even driving.
The parts of the brain that deal with higher-order functions such as judgement and recognition, however, are in deep sleep.
Studies undertaken by Australia’s only team of sleepwalking researchers at the University of South Australia estimate that over a 12-month period sleepwalking affects about 5 per cent of children and 1.5 per cent of adults.
We have known about it for centuries if it is to be believed Shakespeare’s guilt-ridden Lady Macbeth was sleepwalking in the “out, damned spot” scene in Macbeth. However, research team leader and senior lecturer in psychology Dr Helen Stallman says it is a condition that has been largely underresearched worldwide.
Contrary to popular belief, a sleepwalker does not move with closed eyes and arms extended. They are in a disconnected state, misperceiving what they are seeing and unresponsive to those around them.
“Another furphy is that you should never wake a sleepwalker,” says Stallman. “It can be dangerous in certain circumstances not to wake them.
“Most times, though, it is best just to lead them back to bed so as not to disrupt their sleep.”
While the cause is unknown, American studies have linked sleepwalking to a genetic abnormality, but so far a faulty gene has not been identified.
Stallman says her team began researching in 2015 and has already laid solid groundwork by carefully reviewing existing research methodology and identifying gaps for further research into cause, treatment and the impact on not just the sleepwalker but the whole family.
“We’re talking about half a million children [in Australia] and a significant number of adults with this condition, so it potentially affects a large number of families,” she says.
While harmless in itself, sleepwalking has been known to have devastating consequences.
“Fatalities have occurred, for instance, when people fall out of windows, downstairs or when they have left the house and run into traffic,” says Stallman.
“There have also been cases where sleepwalkers when threatened in a dream will lash out and assault their partners.”
Stallman’s interest in sleepwalking was piqued after reading court cases in which sleepwalking was raised as a defence for serious crimes.
The defence when linked to a death, known as homicidal somnambulism, was first tested in Australia in 1950 when Ivy Muriel Cogdon of Carnegie in Victoria pleaded not guilty to murdering her only child, Patricia, 19, when she bludgeoned her to death with an axe as the teenager slept.
During the trial a frail and weeping Cogdon, who had a history of sleepwalking, told the jury she loved her daughter dearly and no longer wanted to live, according to a newspaper report.
Her king’s counsel, Robert Monahan, was able to prove Cogdon, 50, was rattled at the time by the Korean War and had been sleepwalking when she went into Patricia’s room with the axe to save her from what she believed was an attack from a foreign invasion soldier.
The jury acquitted Cogdon but she died two years later in what was then Melbourne’s Mont Park Asylum.
“More than 60 cases of homicidal somnambulism worldwide have raised this defence with mixed results and it is another area we are pursuing in the hope of strengthening the science on which to base this defence,” says Stallman.
She believes her team’s most significant finding so far has been establishing prevalence of sleepwalking in a review of 51 studies involving 100,000 adults and children.
“Some studies report that sleepwalking peaks around the age of 13, but we found it fairly stable across entire childhood and adolescence,” says Stallman.
The research also produced the first systematic review of the scientific evidence underpinning the psychological, pharmacological and other interventions for sleepwalking.
It found no intervention had a methodology that could demonstrate efficacy or effectiveness.
“It did, however, highlight potential treatments and the need for well-designed randomised control trials that include assessment of adverse effects,” says Stallman.
David Kohler and his wife, Tabitha, like the majority of sufferers, have never sought treatment for sleepwalking despite both having a few disconcerting experiences.
Tabitha was six and on holidays when she first experienced sleepwalking.
“We had been learning to dive the day before and I was re-enacting the lesson in my dreams when I stood up on the bed and prepared to dive headfirst onto the floor – luckily my parents woke me before anything happened,” she says.
Since then her most disturbing sleepwalking episode in adult life was when she sat up in bed in terror believing she had rolled onto her then newborn baby, whom she sometimes breastfed in bed. She was woken by her own frantic screams.
These days, says Tabitha, she has become the lightest sleeper in the house and will normally shepherd both her husband and son back to bed when they sleepwalk. She tends to wake herself by bumping into objects.
Both she and David agree that what might seem unusual to other families has settled into a normal and manageable pattern for their family.
Those who do seek treatment are usually experiencing problems, says sleep medicine physician Dr Peter Buchanan, who is attached to Sydney’s Liverpool Hospital and the Woolcock Institute of Medical Research.
“These problems can be, say, if the sleepwalking is so frequent and disruptive that it starts to impact on daytime function,” he says. “It can also become problematic in a new relationship where the partner is either perplexed or upset by the sleepwalking activity.
“Occasionally, they seek treatment because sleepwalking poses potential dangers, for example, if the patient lives in an apartment building where the balcony is open or if they sleepwalk outside their home and on to the streets, putting them at risk of traffic accidents and other dangers.”
Buchanan is also called upon, on average twice a year, to supply reports for courts to consider in criminal cases where sleepwalking is offered as a defence.
He treats adults only and describes available treatments as “less than fully satisfactory”.
“In my experience you don’t ‘cure’ sleepwalking so much as manage it with a multi-model approach that ranges from commonsense advice on avoiding potential dangers to certain medications to suppress sleepwalking activity, usually selected from the benzodiazepine class.”
Benzodiazepines slow the activity of the central nervous system and the messages travelling between the brain and body.
Buchanan says treatment should also factor in any co-existing sleep disorders that may have an impact on the frequency of sleepwalking events.
“This multifaceted approach, in my experience, can achieve a success rate of between 60 and 70 per cent.”
Buchanan says sleepwalkers should also try to develop what is called good “sleep hygiene” that involves regular sleep hours, regular sleep times and modest use of stimulants, including alcohol.
This article was first published in the print edition of The Saturday Paper on Oct 15, 2016 as "Asleep at the heel". Subscribe here.