By Martha A. Simpson, D.O., M.B.A.
Assistant Professor of Family Medicine
Ohio University College of Osteopathic Medicine

CHILD’S GENDER AND HEREDITY PREDISPOSE TO SLEEPWALKING

Question: When I was a boy I was prone to sleepwalking. Now my son sleepwalks. Does this run in families? What causes it?

Answer: Sleepwalking, known as somnambulism by physicians, occurs in about 15 percent of children. It’s most common between the ages of 4 and 15 and affects boys more often than girls. Since it has been found to “run in families,” it is assumed to be an inherited condition. So, your son has two predisposing factors -- heredity and gender.

To understand sleepwalking, I first need to explain normal sleep. Two major stages have been identified based on the eye movement that takes places during them. One is called the REM (rapid eye movement) stage. During this period, you experience vivid dreaming and high levels of brain activity. On the other hand, the NREM (non-rapid eye movement) stage cannot be so simply summarized. It can be understood best by looking at its four subcategories. Stage 1 is the “drowsy” phase -- lasting about 15 minutes -- when you fall into light sleep and are easily awakened. Stage 2 is an “intermediate sleep” period -- accounting for about half of your total sleep time -- when you are more difficult to awaken. Stage 3 is the beginning of deep sleep, and Stage 4 is the deepest sleep stage.

A sleep cycle -- lasting 90 to 100 minutes -- begins with the four stages of NREM. These stages then quickly reverse, and are directly followed by the first REM period, roughly 90 minutes after falling asleep. This cycle -- with slightly varying patterns -- recurs about four to six times each night.
It is in the last two stages of NREM sleep -- during the first three hours of sleep -- that sleepwalking usually occurs. It’s interesting to note that both the time spent in these last two stages and the incidence of sleepwalking decrease with age.

Oftentimes a sleepwalker like your son, will sit up in bed with his eyes open and may mumble nonsensical speech. He may move around and perform simple tasks such as turning lights on and off, but the movements may not be well coordinated. Episodes may be very brief or may last over 30 minutes.
While it can be difficult to awaken a sleepwalker, contrary to popular belief, it won’t do any lasting harm. Often, though, all that’s needed is to redirect him back to bed. Also, sleepwalkers can injure themselves, so you may need to take one or more of the following precautions: place a gate by the stairs, move the sleepwalker’s bedroom to ground level, or make sure upstairs bedroom windows are securely locked.

Although in many cases the exact cause of sleepwalking can’t be determined, it can sometimes be due to anxiety, fatigue or stress. Providing emotional support for children plus a safe nighttime environment can benefit a sleepwalker.

Good sleep hygiene -- such as going to bed at the same time every night, maintaining proper room temperature and avoiding excessive fatigue -- can be of benefit. Restricting fluids in the evening may also help, as the need to urinate can sometimes trigger sleepwalking. The good news is that this condition is usually outgrown in the teenage years, is seldom associated with any serious underlying illness and produces no lasting harm. If your son is having more than a couple of sleepwalking episodes a month, or they last into late adolescence, I recommend that you contact your family physician for help.

"Family Medicine" is a weekly column. To submit questions, write to Martha A. Simpson, D.O., M.B.A., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701. Past columns are available online at http://www.FamilyMedicineNews.org.