A study comparing children 7 to 11 years old with moderate or severe obstructive sleep apnea to children the same age who slept normally found significant reductions of gray matter -- brain cells crucial to most cognitive tasks -- in several regions of the brains of children with sleep apnea. The finding points to connections between this common sleep disturbance and the loss of neurons or delayed neuronal growth in the developing brain.

Source: Untreated sleep apnea in children can harm brain cells tied to cognition and mood