Suddenly and with no warning, a peacefully sleeping child jumps out of bed with a blood-curdling scream. No amount of comforting helps to quell the terror. And then just as quickly, the child is silent again and quietly goes back to sleep, often never even recalling the episode the next day.
A psychotic attack? No. A bad dream? Not exactly. It's a night terror, one of the many sleep disturbances known to afflict most children and adolescents at some time during their lives. Children who experience night terrors are suspended in an altered state of consciousness between deep sleep and dream sleep. Unlike nightmares, which may be recalled in minute detail, youngsters who suffer night terrors often have no recollection of the event.
Night terrors are one of a group of sleep disturbances known as parasomnias. These disturbances range from the benign sleep talking to bruxism (teeth grinding), sleep walking and the most extreme--night terrors.
But despite their sometimes bizarre appearance, sleep problems are a common event of childhood. For many youngsters, they are a kind of rite of passage as a child moves from one developmental brain stage to another.
"Thirty to 40% of all children have a parasomnia attack once or twice during childhood," said Thomas Anders, a physician who directs the division of child and adolescent psychiatry at Brown University Medical School in Providence, R.I. "Less than 1% of children have it as a serious recurrent problem that requires major attention."
But for parents who encounter their children in this altered state of consciousness, the experience can be very scary. "It's as though your child is seeing a dinosaur, as though he is being devoured by animals," said David Dinges, a biological psychologist who does sleep research at the University of Pennsylvania's unit for experimental psychiatry. "They jump out of bed, pulling and screaming and slamming things down.
"It is very frightening, even to me. I remember when my son, Justin, was 4 or 5 and had a night terror. I remember vividly trying to arouse him, and I couldn't get him to wake up. I remember feeling panic."
Sleep disturbances can begin as early as the first year of life. Nightlong video camera studies of babies show that infants sleep for about three to four hours, then wake up.
Some babies are particularly good at putting themselves back to sleep early on in life--a trait that leaves their parents mistakenly thinking that they have slept through the night. Other infants wake and cry for comfort or for food and do not go back to sleep until they have attention from their parents. It is not until the end of the first year of life that most babies are able to sleep six to seven hours before waking.
But for about 20% of youngsters, night wakenings are a regular occurrence that continue through the first two years of life, said William Sonis, director of the mood, sleep and seasonality program at the Philadelphia Child Guidance Clinic. By age 2 to 3, about 11% to 14% of children still wake up regularly, and by age 4, about 8% of parents report that their youngsters still do not sleep regularly all night.
Youngsters who do not sleep through the night either experience one of the parasomnias or they have nightmares. Although it can sometimes be difficult for parents to tell the difference between the two, the general rule of thumb is that night terrors occur in the early part of the night, within the first two to three hours of sleep. Nightmares, on the other hand, happen most often during the early morning hours during the part of sleep known as rapid eye movement (REM) sleep.
Children are more vulnerable to all sorts of sleep disturbances because they fall more quickly into deep, non-rapid eye movement (non-REM) sleep than do adults. During non-REM sleep, the brain rests and restores itself.
REM sleep, by comparison, enables the brain to dream. During REM, muscles are paralyzed, the eyes may twitch rapidly and the heart rate can fluctuate greatly. Four to six times each night, the brain normally cycles between non-REM and REM sleep.
For children who experience frequent sleep disturbances, it appears that this switching mechanism "is immature and slower to develop," said Brown University's Anders.
Boys are three to four times more afflicted with night terrors than girls although researchers do not yet know why. And there is some suggestion that night terrors "seem to run in families," Anders said.
To understand a night terror, imagine having a few shots of alcohol before going to bed. Then shortly after you have drifted off to sleep, there is a sudden, very loud horn outside your bedroom that wakes you up and leaves you very disoriented. "You jump up, run around the room in a very crazy manner and just aren't able to get clear-headed," said Richard Ferber, a physician and director of the Center for Pediatric Sleep Disorders at Children's Hospital in Boston.