If you have not already done so, please read Blog Posts 1 through 5 that describe how sleep is important and beneficial. I will post specific information for parents and children based on my book, “Healthy Sleep Habits, Happy Child.” Please do not be put off by my book’s length. This is a reference book. Read only the topic of interest to you.
Question: Can a sleep-deprived child appear to be unaffected?
Answer: Superficially, yes. But the deeper you look, the more likely deficits will be discovered.
Evidence: One study examined the effects of a single night of experimental sleep restriction (5 hours of sleep allowed) or 3 nights of sleep restriction (7 hours of sleep allowed) in a group of children between 10 and 14 years old. The researchers noted that there were impairments in verbal creativity, abstract thinking and concept formation, and complex problem solving. These higher cognitive abilities are essential for academic performance and success. In contrast, there were no deficits in rote performance or less complex memory and learning tasks.
Conclusion: Our children can and do perform quite well even when mildly sleep-deprived if they are not challenged to write or be creative. Mild sleep deprivation is often trivialized or overlooked because more routine memorization tasks and athletic performances are successfully accomplished. The ability to maintain routine performance despite being sleepy is familiar to every adult who sometimes gets very tired but nevertheless can perform the routine aspects of his or her job fairly well.
The benefits from healthy sleep and the harms from unhealthy sleep are described in Blog posts 1–5. The focus is on brain health because the brain is the only organ in the body that has a requirement for sleep. However, brain health is an unappreciated public health concern (Blog post 38). Also, many sleep-deprived adults are actually unaware that they are mildly or moderately sleep deprived (Blog Posts 84–86).
There is evidence to suggest that the harm to the brain from unhealthy sleep is reversible (Blog Posts 45 and 66) just like having a few alcoholic drinks on a single occasion only temporarily alters brain function. On the other hand, it is also possible that the harm to the brain from unhealthy sleep is irreversible (Blog Posts 50 and 51) just as repeated head trauma may cause permanent brain damage as in Chronic Traumatic Encephalopathy (CTE).
Please do not worry if now and then your child gets a little short on sleep but is well rested most of the time. But I would worry if sleep problems are persistent and severe, because, especially in infants and very young children, persistent and severe unhealthy sleep may prevent the brain from growing or developing properly.
Speculation: Does Chronic and Severe Unhealthy Sleep in Childhood Cause Brain Damage?
Here are some opinions, based on research, that suggest this topic should be taken seriously by parents:
Recent research by Dr. Giulio Tononi tells us that the purpose of sleep is to weaken or prune the unimportant noise coming into our brain so that important signals remain stronger. A 2019 study, led by Professor Shuntaro Izawa, supports this idea that during sleep, pruning or active forgetting is vital for “helping the brain forget new information that is not important.” This culling of information allows more memory resources to be available to us the next day. Dr. Izawa’s research shows that only during REM sleep, certain nerve cells started firing the electrical signals necessary to effectively remove unimportant memories. In adults, experimental sleep restriction primarily leads to deficits in REM sleep, so maybe the brain gets cluttered with unimportant memories, making it hard for us to focus on the present.
This theory, in Dr. Tononi’s words, “predicts that sleep is especially important in childhood and adolescence, times of concentrated learning. In youth, connections between nerve cells are formed, strengthened, and pruned at an explosive rate never approached in adulthood. One can only wonder what happens when sleep is disrupted or insufficient during critical periods in development (Blog Post 131). Might the deficit corrupt the proper refinement of neural circuits? In that case, the effect of sleep loss would not merely be occasional forgetfulness or misjudgment but a lasting change in the way the brain is wired.” Support for this idea comes from animal studies: “Consequences of extremely stressful early-life events leave permanent changes in the brain. This molecular ‘scar’ may act as a predisposing factor in development of psychopathologies later in life. Sleep, particularly REM sleep, appears to be the most sensitive behavioral indicator of the early-life events in adulthood.” Sleep quality, not just sleep duration, is important (Blog Post 15).
Professor Abraham Sadeh performed objective sleep measures on children at age 12 months. Children who had lower quality sleep at 12 months were more likely to have compromised regulation of attention and behavioral problems at 3-4 years of age. Professor Sadeh raised the tentative possibility that “it could be argued that sleep disruptions at an early age interfere with vulnerable brain maturational processes that later result in compromised regulatory capabilities our findings suggest that the impact of sleep deficits at critical stages of early brain maturation could potentially lead to long-term consequences.
In a study by Dr. Salome Kurth, connections between the right and left sides of the brain increased as much as 20 percent over a single night’s sleep in a group of children 2–5 years old. Connections strengthened as the children aged. “Sleep is a key environmental contributor to brain optimization processes and plays a crucial role in brain maturation,” Dr. Kurth concluded. “In critical phases of development [such as walking, talking, problem solving], the maturation of skills not only require cortical activity during waking but also a subsequent period of sleep . There are strong indications that sleep and brain maturation are closely related. I believe inadequate sleep in childhood may affect the maturation of the brain related to the emergence of development or mood disorders.” (Blog Post 131).
To be continued.