Sleep Apnea in Children:Damages Brain Cells, Causes Cognitive Decline

Highlights

• Obstructive sleep apnea (OSA) is a common sleep disorder that affects up to 5% of the children.
• New findings show that children with moderate to severe OSA have significant reductions in the volume of gray matter in several regions of the brain.
• If left undiagnosed and untreated, OSA is likely to impact brain functions, and put cognitive developmental potential at risk.

Children who suffer from moderate or severe obstructive sleep apnea showed evidence of widespread brain cell damage. On comparing children between 7 and 11 years of age who suffered from moderate or severe obstructive sleep apnea to children who slept normally, significant reductions of gray matter were seen in several regions of the brains of children with sleep apnea.

The gray matter contains brain cells that are involved in functions like movement, memory, emotions, speech, perception, decision making and self-control.

Obstructive Sleep Apnea(OSA) is a sleep-related breathing disorder in which there is repeated obstruction to the upper airway, while the person is sleeping. It affects up to 5% of all children.

The obstruction causes its victims to repeatedly stop breathing during their sleep, often for 10 seconds or more and sometimes even for a minute or longer.

These recurrent episodes of obstruction can lead to a drop in the oxygen saturation in the blood. Following these episodes, children will resume fragmented and non-restorative sleep.

OSA in children increases risk for cognitive and behavioral deficits, and poor school performance

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These findings show a connection between sleep apnea and the loss of neurons or delayed neuronal growth in the developing brain.

This study emphasizes the importance of early detection and treatment of children with symptoms of sleep apnea.

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"The images of gray matter changes are striking," said one of the study's senior authors, Leila Kheirandish-Gozal, MD, director of pediatric clinical sleep research at the University of Chicago. "We do not yet have a precise guide to correlate loss of gray matter with specific cognitive deficits, but there is clear evidence of widespread neuronal damage or loss compared to the general population."

Study

For this study, the researchers recruited 16 children with obstructive sleep apnea (OSA) aged between 7 to 11 years and 9 healthy children of the same age, gender, ethnicity and weight, who did not have apnea.

Their sleep patterns were evaluated overnight in the University of Chicago's pediatric sleep laboratory.

Children went through neuro-cognitive testing and had their brain scanned with non-invasive magnetic resonance imaging (MRI). The analysis of the image was then performed.

The researchers compared the scans along with neuro-cognitive test results, to those of the healthy children.

The findings showed significant reductions in the volume of gray matter in multiple regions of the brains of children with OSA.

The reductions were found in:

• frontal cortices which handle movement, problem solving, memory, language, judgement and impulse control
• prefrontal cortices that controls complex behaviors, planning, personality
• parietal cortices that integrates sensory input
• temporal lobe responsible for hearing and selective listening
• the brainstem controlling cardiovascular and respiratory functions

Although these gray matter reductions were rather extensive, the direct consequences can be difficult to measure.

Conclusion

"MRI scans give us a bird's eye view of the apnea-related difference in volume of various parts of the brain, but they don't tell us, at the cellular level, what happened to the affected neurons or when," said co-author David Gozal, MD, professor of pediatrics, University of Chicago.

"The scans don't have the resolution to determine whether brain cells have shrunk or been lost completely. We can't tell exactly when the damage occurred. But previous studies from our group showed that we can connect the severity of the disease with the extent of the cognitive deficits, when such deficits are detectable." Gozal added.

In addition, "we are planning future collaborative studies between the University of Chicago and UCLA that will use state-of-the-art imaging approaches to answer the many questions raised by the current study," said Paul Macey, PhD, who, along with colleague Rajesh Kumar, PhD, led the image analyses at UCLA.

"If you're born with a high IQ - say 180 - and you lose 8 to 10 points, which is about the extent of IQ loss that sleep apnea will induce on average, that may never become apparent. But if your IQ as a child was average, somewhere around 90 to 100, and you had sleep apnea that went untreated and lost 8-10 points, that could potentially place you one standard deviation below normal," Gozal said. "No one wants that."

"The exact nature of the gray matter reductions and their potential reversibility remain virtually unexplored," the authors conclude, but "altered regional gray matter is likely impacting brain functions, and hence cognitive developmental potential may be at risk." This, they suggest, should prompt "intensive future research efforts in this direction."

The study is published in the journal Scientific Reports.

References

1. Leila Kheirandish-Gozal et al. Reduced Regional Grey Matter Volumes in Pediatric Obstructive Sleep Apnea. Scientific Reports; (2017) doi:10.1038/srep44566
2. Sleep Disorder: Obstructive Sleep Apnea (OSA) - (https://www.medindia.net/patients/patientinfo/Obstructive-Sleep-Apnea.htm)

Source-Medindia