SciTech

Health Talk: Sleepwalking

Earlier this month, CBS reported that a toddler in Buena Park, Calif., opened a deadbolted hotel room door and climbed down three flights of stairs. He was found asleep under a nearby parked van. Although this adventurous spirit is characteristic of many children, the boy performed these acts while sleeping!

His behavior is not uncommon; the American Academy of Sleep Medicine (AASM) estimates the prevalence of sleepwalking as up to 17 percent in children and 4 percent in adults. In addition to movement, people have reported eating, talking, driving, or committing crimes while asleep, with no memory of the events. The AASM classifies sleepwalking, or somnambulism, as a disorder “that tends to occur during arousals from slow-wave sleep.” In order to understand what slow-wave sleep is, it is important to know the basic stages of sleep.

Each sleep stage is characterized by specific eye movements, and further segmented according to electrical activity in the brain. Sleep is divided into two main phases, which alternate to form the sleep cycle: rapid eye movement (REM) and non-rapid eye movement (NREM).
REM is characterized by eye movements during sleeping.

NREM is separated into four stages ranging from light sleep (I and II) to slow-wave or deep sleep (III and IV). In NREM sleep, there is very little movement of the eyes and dreams are uncommon. A physician can diagnose a parasomnia, or sleep disorder, by ordering an overnight study to observe a patient’s sleep behavior.

This requires a stay in an accredited sleep center, where a technician monitors the patient with audio/video equipment and physiological recording devices.

This data is compiled as a polysomnogram (PSG) of the body’s behavior during sleep. The PSG includes parameters such as heart rhythm, breathing rate, electrical activity in the brain, and eye and limb movements.After years of compiling polysomnographic data on sleepwalking patients, the AASM has found a number of causes for the condition.

Stress, anxiety, and sleep deprivation can create awakenings during slow-wave sleep that trigger sleepwalking behavior. The public’s increasing appetite for sleep-inducing medications has made parasomnias more prevalent. As of March 2007, the Food and Drug Administration requested that 13 of these drugs carry stronger warnings about unwanted sleep behavior.

In a June 2008 editorial to the journal Neurology, psychologist Mark R. Pressman reflected on the limited amount of detailed sleepwalking data available. Pressman, director of Sleep Medicine Services at Lankenau Hospital in Wynnewood, Pa., believes that it is because clinicians have been unable to observe sleepwalking in laboratory conditions. However, this is about to change. His editorial is refreshingly optimistic because it prefaces an article on a new method to trigger somnambulation in patients.

We may soon be hearing more about sleepwalking, its underlying causes, and potential treatments. Until these changes come to light, the AASM has no strong recommendations for treatment of somnambulation. It suggests that the best methods of prevention are proper sleep hygiene, behavioral therapy, and careful administration of sleep-inducing medication.