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 (Principles and Practice of Sleep Medicine in the Child, by Ferber and Kryger). 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.
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.
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.