Speculation: Does Chronic and Severe Unhealthy Sleep in Childhood Cause Brain Damage?
(Continued.)
When a growing child does not receive enough vitamin D, the result is soft bones (rickets). Vitamin D deficiency causes bone disease that might be severe and cause persistent deformities, especially bowing of the legs. Sleep deficiency impairs brain health (Blog Posts 1–5 and 38). When a growing child does not receive enough quality sleep, might this be severe enough to produce brain damage, either reversible or persistent? The answer is not known. But in the extreme, long-term experimental sleep deprivation in laboratory animals has been shown to permanently damage the brain and even cause death.
Here are some facts that tend to support the opinions described in Blog Post 50:
- Long-term Sleep Disturbances in Children: A Cause of Neuronal Loss (2010): “Sleep loss adversely effects pineal melatonin production which causes disturbance of circadian physiology of cells, organs, neurochemicals, neuroprotective and other metabolic functions. The most convincing evidence for permanent damage resulting from sleep loss comes from cellular studies in which animal experiments are indispensable. There is increasing evidence that even brief periods of total sleep loss may permanently imprint on neuronal plasticity. For example, during critical developmental periods the adverse effects of sleep loss on the visual system have been clearly shown. Sleep deprivation, depending on the severity, leads to genetic, cellular, metabolic, electrical, neurotransmitter, and other changes. Prolonged sleep loss causes cellular stress and when the defense mechanisms are no longer able to cope, permanent neuronal damage may occur. The effects of cellular stress may be cumulative throughout life. Melatonin, which has powerful neuroprotective properties, has a central role in sleep deprivation since during sleep disturbances melatonin production is often reduced and/or disturbed [Emphasis added]”.
- Childhood Sleep Disturbances and White Matter Microstructure in Preadolescence (2019): “A recent systematic review suggested that inadequate sleep may be associated with differences in brain function and structures; for example, short sleep duration and smaller hippocampal grey matter occur in the brain of healthy 11-year-old children. Our research group previously showed that children with more sleep disturbances from age 2 years onwards had smaller gray matter volumes and thinner prefrontal cortex at 7 years. These imaging studies of sleep have primarily focused on the macrostructural properties of the brain (e.g., brain volume). This study explored the association between sleep problems during childhood and the brain’s white matter microstructure in preadolescence. Childhood sleep problems at 1.5, 2, and 5 years of age were associated with less white matter microstructure integrity at age 10 years. Sleep disturbances at age 10 were not related to white matter microstructure. Our results imply that childhood sleep disturbances have long-term associations with white matter development. The rate of myelination of white matter is particularly high in the first postnatal years. Our results show that early neurodevelopment may be a period of particular vulnerability to sleep problems. This study cannot demonstrate causality but suggests that preventive interventions addressing sleep problems should be further explored to test whether they impact adverse neurodevelopment. Impaired sleep should be early recognized and warrants early sleep intervention programs. Next to improving sleep, these interventions might lead to better neurodevelopmental outcomes [Emphasis added].”
Causality
Here are three possible paths of causality:
- Congenital factors, factors present at birth (inherited genetic factors or acquired in utero), effect brain maturation which, in turn, causes both sleep problems in young children and adverse structural or physiological manifestations in the brain that are detectable when the child is older.
- Parents create unhealthy sleep habits in their child and the child’s sleep deprivation adversely effects brain maturation.
- Both. The combination of a vulnerable child and parent-caused unhealthy sleep is necessary for sleep problems and impaired brain maturation to appear.
Good News
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.
It is never too early to help your child sleep better.
You can begin to help your child sleep better when you come home from the hospital with your newborn (see ‘What a Parent Can Do’).
My research shows that temperament at 4-5 months of age is not like a fingerprint; it is not a permanent marker of your baby’s personality (Blog Post 48). Going forward, practicing healthy sleep habits will tend to make your child temperamentally easier:
- More positive mood (more smiles, laughs, coos) and less negative mood (less fussing/crying)
- More mild (less intense)
- More adaptable (more ease in adjusting to new circumstances or a change in routine)
- More approaching (less withdrawing to something new)
It is never too late to help your child sleep better.
In a study conducted by Dr. Yvonne Kelly, children with nonregular bedtimes examined at age 3, 5, and 7 years had more behavioral difficulties at age 7 than children with regular bedtimes. The effect of nonregular bedtimes was cumulative—the more years of nonregular bedtimes, the worse the behavior. So the effect of nonregular bedtimes builds up throughout early childhood. The good news is that the harm is reversible. That is, when children change from nonregular to regular bedtimes, they show improvements in their behavior.
Small amounts of extra sleep benefit older children and teen-agers (Blog Post 6)
The United States of America Department of the Army documents how more sleep and better quality sleep benefit young adults (Blog Posts 1–5)
