A mother's suggestion that her son, TV personality Chris Hyndman, plunged to his death while sleepwalking has shone a light on the dangers associated with the disorder.

Glenda Hyndman told the Toronto Star that she believed her son fell to his death while sleepwalking on the terrace of the downtown Toronto home he shared with his professional and personal partner Steven Sabados.

Sleep researchers say there have been documented cases in which sleepwalkers engage in very complex activities and wind up inflicting harm on themselves or others. However, they say those cases make up the extreme minority of the situations they encounter.

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Hyndman, co-star of CBC fashion and design show "Steven and Chris," was found lying in an alleyway just outside of his home late on Monday evening. Police have not identified a cause of death but have suggested that there is no criminal investigation underway.

Colleen Carney, director of the Sleep and Depression Laboratory at Ryerson University, said Hyndman's death would be a tragic rarity if it was caused by a fatal sleepwalking accident.

"Injuries during sleepwalking tend to be mild, but there's tremendous variability in sleepwalking and also the severity of it," Carney said in a telephone interview.

Somnambulance is already an unusual disorder to encounter in adults.

Dr. Sat Sharma, medical director for Toronto's Centre for Sleep and Chronobiology, said that less than one per cent of the adult population suffers from the condition that is most prevalent in childhood.

Sharma said the majority of sleepwalkers confine themselves to wandering aimlessly in their homes and usually find themselves unable to perform complex tasks like unlocking doors or taking themselves further afield.

Such actions are possible, though, for those with particularly grave conditions. Sharma said risk of injury is "very serious" in such instances.

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High-profile examples of this phenomenon often focus on sleepwalkers inadvertently harming others in their somnambulant state, sometimes with tragic consequences.

In 1987, Kenneth Parks of Pickering, Ont., drove 23 kilometres to his in-laws' Toronto home, took a knife from their kitchen and used it to attack his father-in-law before ultimately beating his mother-in-law to death. Parks argued that his horrific actions took place while he was asleep, an argument courts accepted in both 1988 and 1990 when the crown appealed Parks' acquittal.

Last month, a similar defence was used to win a new trial for an Ontario man who was convicted in 2012 of sexually assaulting a woman at a party. In ordering a retrial for Ryan Hartman, the Ontario Court of Appeal said the key question will be to determine whether or not he suffered from sexsomnia at the time of the attack.

Sharma said sleepwalking disorders can take unusual forms, adding the past five to 10 years have seen a spike in people admitting to eating in their sleep.

Hyndman's mother told the Star that her son frequently "foraged" for food without being aware of doing so.

Sharma said this condition, too, poses risks.

"People have eaten cigarettes out of an ashtray, or they would eat something that's just not a food product," he said, adding that unexplained weight gain is another alarming side effect of the disorder.

Carney said the most common way to address the more serious sleep ailments is to take safety precautions to limit or prevent injury.

She said sleepwalkers' loved ones are often told to be vigilant about locking doors or securing dangerous objects. In especially serious cases, Carney advises installing an alarm to sound the alert if a sleepwalker manages to leave the house.

Glenda Hyndman could not be reached for comment, and it is unknown whether such safety measures were in place in Hyndman's home.

Carney said one popular misconception about sleepwalkers is that they should not be awakened if a family member finds them on the move.

"That myth, 'don't wake a sleepwalker,' we say, 'sure you can,'" she said. "We want to protect them, so get them back into bed."