Sleep in Children:
A Whistlestop Tour
“If sleep does not serve an absolutely vital function, then it is the biggest mistake the evolutionary process ever made.” Rechtschaffen
We spend more than a third of our lives asleep, and are very aware of how we feel at work when we do not get a “full” night’s sleep. However, when we see the parents of children who frequently tell us that their 3-year child continues to wake through the night, aside from offering sympathy and perhaps melatonin, do we honestly delve deeper? Lack of sleep can have far-reaching negative effects for both the child and their family, and create disruption in school and beyond. Here’s a little rundown of sleep physiology, common childhood sleep disorders, and what help you can offer to kids and their families.
The science of sleep
As a self-confessed sleep geek, I find sleep physiology fascinating, although I cannot claim to understand it all! Sleep can be defined as “A reversible state of reduced awareness of and selective responsiveness to the environment”. It is broadly classified into REM (Rapid Eye Movement) and non-REM sleep, and non-REM sleep is divided into 4 further stages, as illustrated by the following hypnogram:
Sleep progresses in a series of cycles through the night. Once the pre-conditions for sleep (e.g. tiredness, dark and quiet room, correct temperature) have been satisfied, an individual goes from the awake state through Stages 1, 2 and 3 (previously 3 and 4) of non-REM sleep. Stage 3 (known as Slow Wave Sleep) is the deepest stage of sleep. After a period in this stage, the cycle reverses back up to Stage 1, and then enters REM sleep, before going back through the stages in a new cycle. Individuals are most likely to wake naturally during REM sleep, and often do for very brief periods during the night before going back to sleep. An average sleep cycle lasts between 100-120 minutes, and is usually shorter in children.
Why is sleep so important?
The average child spends almost half of his or her life asleep. Sleep underpins all aspects of a child’s physical and cognitive development due to the processes of growth hormone secretion and protein synthesis during sleep. It also aids memory consolidation and gives a child respite from daytime stimuli, thus contributing to their social and emotional well-being. Persistent lack of restorative sleep can lead to behavioural difficulties such as hyperactivity, and can adversely affect academic performance due to impaired concentration. Children may also display low mood, and family stress levels can go through the roof when one child’s sleep problems disrupts the entire household’s sleeping pattern. Unfortunately, the omnipresence of hand-held mobile devices and relentless social media are exacerbating sleep problems, so we need to take sleep seriously!
The following is a rough guide to what is a “normal” amount of sleep in a child:
11 hours for pre-schoolers (2-5 yrs)
10 hours for pre-adolescents (5-11 yrs)
9 hours for adolescents (11+ yrs)
Sleep disorders in children
There are 4 main sleep-related problems in children:
Dyssomnias: disorders of initiating and maintaining sleep
Hypersomnias: excessive sleepiness
Parasomnias: abnormal activity or behaviour during sleep
Sleep disordered breathing
Short of turning this article into a textbook chapter on sleep disorders, make sure you look at a few pointers in the history to help make a diagnosis:
What are bedtime routines like? If the child needs their parent in bed with them or a particular bedtime story to help them fall asleep, and do not have this when they wake during the night, they may not be able to settle back down. Children need to develop their own self-soothing skills.
How long after a child falls asleep do they have problems? This will help to distinguish which stage of sleep the disorder arises from, e.g. hypnagogic/hypnapompic jerks or hallucinations during the transition from awake to sleep and vice versa; night terrors in the first few hours of sleep during transition from non-REM to REM sleep.
Differentiating parasomnias from nocturnal seizures? This might be quite tricky on history alone, and you may need some help from your neurology colleagues on this one in the form of a sleep EEG!
So what can I tell parents and children?
Once you have ruled out any red flags associated with sleep disorders (including epilepsy masquerading as a parasomnia), you can offer a few words of wisdom:
Explain the normal sleep patterns of infants and children. In order to address sleep problems, parents need to be familiar with normal sleep duration.
Advice on sleep hygiene. Discuss the principles of sleep hygiene (see table below), and try to explore why parents may not be adhering to them, e.g. inconsistency between 2 parents.
Ask about parental sleep deprivation. We often forget to do this! Parents who are sleep deprived can also have low mood and poor coping skills.
Leave melatonin as a last resort! Generally speaking, we tend to use melatonin in children with neurodevelopmental disabilities, and only then after trialling sleep hygiene measures. Exogenous melatonin acts as a trainer for the biological clock, like light, and does not impact on endogenous melatonin production. It can therefore help children with severe visual impairment due to their disordered circadian rhythm. Positive effects have also been reported in children with ADHD and delayed sleep phase due to their low melatonin levels at the start of the night. Although melatonin can be very useful in the short-term for children with chronic sleep onset insomnia, the long-term effects are still unknown, and it is not a substitute for good sleep hygiene practices.
Sleep hygiene factors
So there you are! A whistle-stop tour of sleep in children. Remember, sleep is an essential part of child health and development, so even asking the question “How does your child sleep at night?” may open diagnostic doors for you.
Southampton Sleep Training courses: https://www.facebook.com/southamptonsleeptraining/
O’Neill MB, Mary M. Diagnosing and treating common problems in Paediatrics: the essential evidence based study guide.