In this month’s British Medical Journal, there’s a report on a study demonstrating the relationship of sleep to brain development in kids. It is called the Millennium Cohort Study, and it followed 11,000 children. Those children who demonstrated irregular bedtimes up to the age of three were the most negatively affected when it came to reading, math skills and spatial awareness. When followed over time, they continued to lag developmentally even by the age of seven — and girls more than boys. The authors concluded that the first three years of life seem to be a particularly sensitive time for sleep and its relationship to brain development.
The findings are similar to a smaller Canadian study published in the journal Sleep in 2008. This study found that children sleeping less than ten hours a night before age three were more likely to exhibit language and reading problems as well as ADHD. In both studies, these problems persisted despite improvement in total sleep time after the age of three.
What we are seeing here is the relationship of sleep to neuroplasticity. Neuroplasticity relates to structural and functional changes in the brain brought on by training and experience. It is the ability of the brain to change by increasing brain tissue called gray matter and to alter the brain circuits called synapses. We know that adults are capable of these changes but on a much smaller scale. It would appear that the most crucial period for these kinds of brain changes is probably during the first three years of life. In fact, that is one of the reasons that children can recover from head trauma much more completely than adults can. It also explains the fact that if the entire left hemisphere is removed in a three or four year old, that child can still develop normal language skills. This is not possible in an adult.
Why Your Child Needs Lots of Sleep
So how does sleep enter into this? We know that young children exhibit the largest amount of slow wave (deep) sleep. Recent studies have correlated this slow wave sleep with brain development. In fact, certain types of brain scans have demonstrated that regional areas of the brain receiving these slow waves show increased growth and development in response. REM sleep is also important and plays a major role in developing the visual related parts of our brain. Finally, recent works show the production during sleep of cerebral proteins required for these changes.
So what is the take home message of these studies? Probably that sleep is much more important in childhood brain development than we ever realized before. It is very important that your toddler get sufficient sleep – and that, as the British study showed, you establish a regular bedtime to which your child adheres. His or her future may depend upon it.
