A new study from the University of Chicago compared children between 7 and 11 years old with sleep apnea to children who slept normally. Findings showed that there were significant decreases in gray matter in various regions in the brains of the sleep apnea children. Gray matter is responsible for memory, emotions, perception, speech, movement, self-control, and decision-making.
Sleep apnea affects approximately 5% of children in the world, so these findings point to a connection between delayed growth of the developing brain and sleep disturbances. The noticeable and proven gray matter reduction in children with sleep apnea – a treatable disorder – adds another reason for parents to consider getting early treatments for their child if there are symptoms of sleep apnea.
Director of pediatric clinical sleep research out of UC, Dr. Leila Kheirandish-Gozal, notes that these findings are astonishing. There is no precise guide to link cognitive deficits with gray matter loss; however, evidence shows a widespread problem of neuronal damage and loss when compared to children of the same age without any conditions.
These findings were published in Scientific Reports on March 17. Researchers analyzed 16 children with a diagnosis of obstructive sleep apnea (OSA). The children stayed overnight in UC’s pediatric sleep laboratory to have their sleep patterns analyzed throughout the night. Additionally, all children underwent brain scans, MRI, and neuro-cognitive testing. Scientists from the University of California in Los Angeles analyzed the images.
Those analyses were compared to the MRI and neuro-cognitive tests from nine healthy children from the general population that matched the gender, age, weight, and ethnicity of the children with sleep apnea. The results for the 16 OSA children were also compared to 191 MRI’s of children who were already part of an MRI database in the National Institutes of Health.
The gray matter in brains of the OSA children was significantly reduced in several regions. These regions included the prefrontal cortices (responsible for planning, personality, and complex behavior), the frontal cortices (movement, memory, judgement, language, problem solving, and impulse control), the parietal cortices (integration of sensory input), the temporal lobes (selective listening and hearing), and the brainstem (control of respiratory and heart functions).
The consequences of reduced gray matter may be obvious on the scans and comparisons, but the true effects are difficult to measure.
Co-author of the study, Dr. David Gozal from UC, notes that while the MRI scans provide a good amount of information regarding the difference in volume levels within the brain of apnea patients, it is still unclear how and when the neurons are affected at a cellular level. MRI scans are not designed to determine the size, movement, and presence of brain cells. From the MRI, there is no way for scientists to determine when the damage and loss occurred. However, prior studies from this same group connected the cognitive deficits with disease severity, when the deficits can be detected.
Future collaborative studies with UCLA are underway, which will use state-of-the-art technology and imaging techniques to attempt to answer the questions raised in this study. Without further research and cognitive function tests before the onset of OSA, there is no way to measure how neuron loss affects functioning.
As an example, someone who is born with an IQ of 180 may lose 8 to 10 points on that scale because of sleep apnea; however, that may never be apparent. If the child’s IQ is average (between 90 and 100) and they sustain that drop in IQ because of sleep apnea, that could place them below the national normal average.
It may be too soon to measure to effects in children of this age group. Studies that connected higher intelligence with increased gray matter are well-documented, but only in adolescents that are an average age of 15.4 years.
The potential to reverse the effects of gray matter reductions are essentially undiscovered; however, it is likely that decreased gray matter in so many areas of the brain interferes with brain functioning and will put the child at risk of developmental delays. This should prompt detailed research to determine the best ways to prevent severe cognitive delays in children.
Rachael Herman is a professional writer with an extensive background in medical writing, research, and language development. Her hobbies include reading, traveling, and cooking.
© 2021 American Sleep Association.