Dr. Greene's Answer
Within fifteen minutes of your daughter’s falling asleep, she will probably enter her deepest sleep of the night. This period of slow wave sleep, or deep non-REM sleep, will typically last from forty-five to seventy-five minutes. At this time, most children will transition to a lighter sleep stage or will wake briefly before returning to sleep. Some children, however, get stuck — unable to completely emerge from slow wave sleep. Caught between stages, these children experience a period of partial arousal.
Partial arousal states are classified in three categories: 1) sleep walking, 2) confusional arousal, and 3) true sleep terrors. These are closely related phenomena that are all part of the same spectrum of behavior.
When most people (including the popular press and popular parenting literature) speak of sleep terrors, they are generally referring to what are called confusional arousals by most pediatric sleep experts. Confusional arousals are quite common, taking place in as many as 15% of toddler and pre-school children. They typically occur in the first third of the night on nights when the child is over-tired, or when the sleep-wake schedule has been irregular for several days.
A confusional arousal begins with the child moaning and moving about. It progresses quickly to the child crying out and thrashing wildly. The eyes may be open or closed, and perspiration is common. The child will look confused, upset, or even “possessed” (a description volunteered by many parents). Even if the child does call out her parents’ names, she will not recognize them. She will appear to look right through them, unable to see them. Parental attempts to comfort the child by holding or cuddling tend to prolong the situation. Typically a confusional arousal will last for about ten minutes, although it may be as short as one minute, and it is not unusual for the episode to last for a seemingly eternal forty minutes.
During these frightening episodes, the child is not dreaming and typically will have no memory of the event afterwards (unlike a nightmare). If any memory persists, it will be a vague feeling of being chased, or of being trapped. The event itself seems to be a storm of neural emissions in which the child experiences an intense flight or fight sensation. A child usually settles back to quiet sleep without difficulty.
These are very different from nightmares. Nightmares are quite common, occurring in about 60% of children in the preschool years. You won’t become aware of your child’s nightmares until after she awakens and tells you about them. They are scary dreams that usually occur during the second half of the night, when dreaming is most concentrated. A child may be fearful following a nightmare, but will recognize you and be reassured by your presence. She may have trouble falling back asleep, though, because of her vivid memory of the scary dream.
True sleep terrors are a more intense form of partial arousal. They are considerably less common than confusional arousals, and are seldom described in popular parenting literature. True sleep terrors are primarily a phenomenon of adolescence. They occur in less than 1% of the population. These bizarre episodes begin with the child suddenly sitting bolt upright with the eyes bulging wide-open, and emitting a blood-curdling scream. The child is drenched in sweat with a look of abject terror on his or her face. The child will leap out of bed, heart pounding, and run blindly from an unseen threat, breaking windows and furniture that block the way. Thus true sleep terrors can be quite dangerous, in that injury during these episodes is not unusual. Thankfully they are much shorter in duration than the more common confusional arousals of the pre-school period.
The tendency toward sleepwalking, confusional arousals, and true sleep terrors often runs in families. The events are often triggered by sleep deprivation or by the sleep schedule’s shifting irregularly over the preceding few days. A coincidentally timed external stimulus, such as moving a blanket or making a loud noise, can also trigger a partial arousal (which again shows that the event is a sudden neural storm rather than a result of a complicated dream).
Interestingly, a study published in the journal Pediatrics, showed that children who have recurrent partial arousal states may also have other sleep disorders (including sleep disordered breathing and restless leg syndrome) that may benefit from a physician’s care.
Treatment usually involves trying to avoid letting the child get over-tired, and trying to keep the wake/sleep schedule as regular as possible. When an event does occur, do not try to wake the child — not because it is dangerous, but because it will tend to prolong the event. It is generally best not to hold or restrain the child, since her subjective experience is one of being held or restrained; she would likely arch her back and struggle all the more. Instead, try to relax and to verbally comfort the child if possible. Speak slowly, soothingly, and repetitively. Turning on the lights may also be calming. Protect your child from injury by moving furniture and standing between him or her and windows. In most cases the event will be over in a matter of minutes. True night terrors, or bothersome confusional arousals, can also be treated with medications, hypnotherapy, or with other types of relaxation training.
Recently, my youngest son was having a confusional arousal, and his mother observed that these events are most common at the same ages that children are becoming aware of the bladder feeling full during sleep. Perhaps some of these kids just need to go to the bathroom? We stood him in front of the toilet, and he urinated, still not awake. The episode faded abruptly, and he returned to sleep. The calm was dramatic.
Was this a coincidence? Or might this be a revolutionary new help for parents whose kids have these frightening episodes? A number of readers have tried this approach. Most said it worked wonders; a few said it had no effect. If you try it, let me know the results, either way. Together we can learn more about the wonder and mystery of sleep in children. I have sat with my children through confusional arousals, and know how powerfully these episodes tug at a parent’s heart. Just understanding what they are (normal childhood sleep phenomena that children outgrow — not a sign of maladjustment or the result of bad parenting) helps tremendously.
References and Resources
Christian Guilleminault, Luciana Palombini, Rafael Pelayo, Ronald D. Chervin; Sleepwalking and Sleep Terrors in Prepubertal Children: What Triggers Them? Pediatrics January 2003
Nathan J. Blum, William B. Carey; Sleep Problems Among Infants and Young Children. Pediatr Rev March 1996