Sleep disorder tied to brain ills in kids.

Children who temporarily but repeatedly stop breathing while asleep display learning problems accompanied by chemical irregularities in critical brain areas, according to a new investigation.

A team led by Ann C. Halbower of Johns Hopkins University School of Medicine in Baltimore focused on kids ages 6 to 16-most from poor, black families--with obstructive sleep apnea (OSA). Symptoms of this condition include loud snoring, interrupted sleep, constant fatigue, and concentration problems. OSA affects about 2 in 100 children.

Compared with 12 healthy youngsters free of sleep problems, 19 children diagnosed with OSA scored especially low on IQ tests and on measures of learning and word memory. Brain scans conducted on six kids in each group indicated that the children with sleep apnea had unusually low amounts of three substances produced in the hippoeampus and the frontal cortex, which are learning-related brain regions.

It's not known whether sleep apnea causes these brain problems in children or vice versa, Halbower's group notes in the August PLoS Medicine. It's also unclear whether administration of medication to boost the critical brain substances will ease symptoms of severe sleep apnea.

The researchers theorize that factors other than sleep apnea, including poverty and, in many cases, obesity, also contributed to neural problems in these children.

Related imaging studies have previously identified damaged or misshapen areas of the frontal cortex, hippocampus, and cerebellum in adults with sleep apnea.--B.B.