"I think Denis' terrified scream is permanently etched in my memory," says Dawn Eaton, mother of 4-year-old Denis. "That scream was the beginning of a horrible night. I wanted to get to him as quickly as possible to reassure him. When I got to his room.his bed was empty! I found him in the corner of his closet, sitting in a fetal position, eyes wide open. I spoke to him, but he ignored me, and when I tried to pick him up he recoiled and growled like a bear. The look on his face convinced me that whatever he saw, or thought he saw, really scared him."

At the suggestion of Denis' pediatrician, Eaton consulted a pediatric neurologist, who diagnosed her son's problem as a sleep disorder called night terrors. Symptoms of night terrors may include screaming, sweating, increased heartbeat, confusion, agitation, unresponsiveness and violent shaking or flailing. This sleeping disorder affects only 2 to 3 percent of children, usually between the ages of 2 and 6.

What Are Night Terrors?
According to Dr. Denie Irdeb of the Emory University/Egelston Children's Hospital Sleep Center, night terrors are one of a group of sleep disorders that include sleep walking, sleep talking and Confusional Disorder. These four disorders are known as Parasomnias or "partial wakings" because they occur when a person is half asleep and half awake. All four of these problems interrupt sleep during the first half of the night; usually about an hour and a half after falling asleep when the child's brain is in transition from one sleep stage to another. Some researchers believe that an immature sleep cycle may be one reason these sleep disorders seem to strike young children.

To understand how sleep cycles work, imagine a "sleep roller coaster." The top of every hill equals very light sleep and the valleys between the hills equal very deep sleep. Our imaginary sleep coaster begins at the top of a hill, or the area of very light sleep. Soon the train starts to move downhill. It arrives at the bottom, or the area of very deep sleep. But the train and the child cannot stay at the bottom (in deep sleep) all night. It must go back up the next hill, traveling again toward the area of light sleep. In adults and children older than 6, the train travels very smoothly up and down the hills, moving in and out of deep and light sleep all night. But a preschooler's train is not as experienced, so the trip is not as smooth. It easily rolls downhill into deep sleep, but it has trouble returning to the light sleep area at the top of the next hill. So, young children may get stuck halfway up the hill, or halfway between deep and light sleep. This is when night terrors and other sleep disorders occur.

During a night terror, parents may be as frightened as the child because the child's behavior may be bizarre or even spooky. As the terror begins, the child, who is sound asleep, suddenly sits up or stands up out of the bed and begins to scream or call out for help. If mom or dad tries to talk, the child will not respond, though she or he may shout one or two words to try to get rid of the thing that is frightening them. The child's eyes are open very wide and the pupils are dilated. The child seems to be looking at the parents, but will not interact with them. According to Dr. Irdeb, "A child in sleep terror has seen something terrifying in a dream, and uses semi-purposeful movements to deal with their intense fear. Because movements may include kicking, waving arms or punching the air with fists, it is necessary for parents to remove any object that may harm the child or siblings."

Dr. Irdeb recommends, "When the child begins to have this terror, parents should never try to restrain the child." In fact, he says that parents should not interfere in any way. "It is hard to just watch, but it is very important to refrain from any interaction with the child. The parents must wait it out." He stresses they should stay close enough to prevent the child from injuring himself, but stay out of the child's line of fire or path of movement.

Nightmare or Night Terror?
Both nightmares and night terrors may begin with a terrifying scream, but otherwise have little in common. Unlike the child's unresponsive behavior during night terror, a fearful scream after a nightmare is usually followed by an urgent request: "Mom! Come here! I had a bad dream!" When mom or dad arrives, the child is still in bed, but is wide awake. She vividly remembers the bad dream, often wants to talk about it, and feels better after sharing the details. At first, her actions are nervous, shaky and excited or scared, but after her parents' hugs, kisses and perhaps a glass of warm milk, she begins to settle down. She may ask one of her parents to sleep with her or may ask to sleep in their bedroom, but will almost always go back to sleep if the parent is firm and reassuring.

The following chart is a good checklist to determine whether your child is having a bad nightmare or is suffering from night terrors. Place a checkmark beside the statement that best describes your child's behavior during his or her nighttime waking episode.

What Causes Night Terrors?
Doctors are not sure what causes these disorders, but research indicates that they run in families. Most professionals agree that terrors are somehow linked to physical immaturity, which contributes to difficulty progressing through sleep cycles.

There are several things which may trigger a night terror. Illness, particularly with fever; certain medications; increased stress; and an overactive, extremely busy day have all been suspected of triggering night terrors. In the last 10 years, sleep clinics have seen more and more night terror patients who are overscheduled, stressed out from a week of soccer practice, piano lessons, gymnastics, clubs and other after-school activities.

Violent, action-packed television shows or movies, especially viewed after dinner, have also been linked to night terrors. Most importantly, lack of sleep and/or an inconsistent sleep schedule is a strongly suspected link. It is extremely important that parents put children to bed on time because allowing them to stay up past bedtime makes them overtired, and may trigger the terror. Check with your pediatrician for the recommended number of hours of sleep for your child's age group.

What Can Parents Do?
If you suspect your child may be a victim of night terrors, it is important you see a doctor. Unfortunately, many pediatricians do not recognize terror symptoms, and often diagnose typical nightmares. As a parent, it is important for you to trust your instincts. Ask for a referral to a pediatric neurologist, or call a local sleep study center and ask if they offer a free consultation. If not, ask the center to send sleep disorders information to both you and your family doctor.

The most important thing a parent can do is to keep a detailed sleep diary, beginning with the first episode of nighttime waking. The diary should include an overview of the child's evening, and note any of the child's comments about things that happened at preschool or daycare. In addition to activities, the diary should also include the contents of the evening meal and after-dinner snacks, the child's overall evening disposition and a brief description of television shows or movies watched.

Finally, ask parents and grandparents about family history of any type of sleep disorder. Note any remarkable memories, including sleep walking, sleep talking, nightmares and bedwetting. Sketch a chart of family members and list each person's sleep history beside his or her name.