A wake-up call for parents of children with sleep apnea

[Guest guest]

A wake-up call for parents of children with sleep apnea

http://www.news-medical.net/?id=19746

In what is believed to be the first study showing neural changes in

the brains of children with serious, untreated sleep apnea, s

Hopkins researchers conclude that children with the disorder appear

to suffer damage in two brain structures tied to learning ability.

Writing in the journal Public Library of Science Medicine, the

Hopkins investigators say they compared 19 children with severe

obstructive sleep apnea (OSA) to 12 children without the disorder.

Using a special type of MRI, researchers identified changes to the

hippocampus and the right frontal cortex. Next, using IQ tests and

other standardized performance tests that measure verbal performance,

memory and executive function, researchers were able to link the

changes in the two brain structures to deficits in neuropsychological

performance.

The hippocampus, a structure in the temporal lobe, is vital to

learning and memory storage, while the right frontal cortex governs

higher-level thinking, such as accessing old memories and using them

in new situations.

" This should be a wake-up call to both parents and doctors that

undiagnosed or untreated sleep apnea might hurt children's brains, "

says lead author Ann Halbower, M.D., a lung specialist at the s

Hopkins Children's Center. " This is truly concerning because we saw

changes that suggest brain injury in areas of the brain that house

critical cognitive functions, such as attention, learning and working

memory. "

While researchers have known for years that fragmented sleep,

interrupted breathing and oxygen deprivation - all hallmarks of sleep

apnea - harm children's learning ability and school performance, this

is the first time they have linked changes in the brain's chemistry

to the syndrome in children, Halbower believes.

" We cannot say with absolute certainty that sleep apnea caused the

injury, but what we found is a very strong association between

changes in the neurons of the hippocampus and the right frontal

cortex and IQ and other cognitive functions in which children with

OSA score poorly, " Halbower says.

Children with OSA had lower mean IQ test scores (85) than children

without OSA (101). Children with OSA also performed worse on

standardized tests measuring executive functions, such as verbal

working memory (8 versus 15) and word fluency (9.7 versus 12).

Using magnetic resonance spectroscopic imaging, which plots peak

levels of brain chemicals in the form of graphs, researchers compared

the ratios between each two of three chemicals - N-acetyl aspartate

(NAA), creatine and choline - in children with apnea and in those

without. The hippocampus and the right frontal cortex of children

with sleep apnea showed altered ratios of these neurochemicals that

are not specific to any one disease but indicate injury to brain

cells. Next, researchers plan to study whether the ratios will return

to normal once the sleep apnea is treated.

In both children and adults, untreated sleep apnea has been linked to

cardiovascular problems and learning and memory deficits. However,

the cognitive effects of untreated apnea might be far more damaging

in children than in adults, researchers point out, because they occur

during critical developmental periods. The frontal cortex matures

throughout the teen years and continues well into the 30s, and

researchers fear that childhood injury to this area might lead to

long-term cognitive deficits.

Obstructive sleep apnea affects 2 percent of children in the United

States, but it is unclear how many of these suffer from severe apnea.

Halbower estimates that up to 17 percent of sleep apnea patients seen

at the Children Center's sleep clinic have the severe form.

Sleep apnea occurs because of partial or complete obstruction of the

airways during sleep due to anatomic and/or neuromotor factors. In

children, the leading cause of sleep apnea is enlarged tonsils and

adenoids, and the first line of treatment is surgical removal.

Another treatment is wearing a special mask at night to ensure smooth

airflow and uninterrupted breathing during sleep.

Researchers from the Kennedy Krieger Institute in Baltimore and the

University of Pennsylvania participated in the study. Co-authors from

s Hopkins include Mahaveer Degaonkar, M.D., Barker, M.D.,

Earley, M.D., Philip , M.D., and Mark Mahone, M.D.

Researchers from other institutions include Cristine Prahme, M.D., of

the Kennedy Krieger Institute, and Carole Marcus, M.D., of the

University of Pennsylvania School of Medicine.

The research was funded in part by the Sanitarium for

the Children of Baltimore City and the General Clinical Research

Center at The s Hopkins University School of Medicine.