Cause of SIDS?

Research links SIDS to brain defect
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PM - Wednesday, 1 November , 2006 18:38:00
Reporter: Kathryn Roberts
MARK COLVIN: Researchers in the United States believe they've uncovered the mystery of cot death - the mysterious syndrome which takes the lives of almost 60 Australian babies every year.They believe they've found strong evidence that Sudden Infant Death Syndrome, or SIDS, is a biological problem, which can be explained by a brain abnormality. Australian medical researchers have cautiously welcomed the findings.Kathryn Roberts reports.KATHRYN ROBERTS: Sudden Infant Death Syndrome, or SIDS, is every new parent's fear.And those who lose a child to SIDS suffer not only the grief of loss, but the pain of not knowing why it happened.Awareness campaigns like Red Nose Day have helped reduce the rate of cot death, but doctors would like to be able to prevent it altogether.Now a team of US neuroscientists at the Children's Hospital in Boston believe their research provides the strongest evidence yet that SIDS is not a mystery disease but has a biological basis.Roger Byard is Professor of Pathology at the University of Adelaide. He believes the research is significant.ROGER BYARD: They've confirmed previous findings about an abnormal transmitter in the brain in SIDS, they've also shown that the abnormalities are probably more extensive than we originally thought, and they've also found that the boys who died of SIDS actually had greater abnormalities than the girls, which may in part explain why we get more boys who die of SIDS than girls. KATHRYN ROBERTS: The research in the latest Journal of the American Medical Association identified abnormalities in the brainstems of babies who'd died suddenly.The team, led by neuroscientist, Dr David Paterson, compared autopsy samples from the brainstems of 31 babies who'd died from SIDS to another 10 babies who'd died from other causes.They found defects in nerve cells that make and use serotonin - a chemical in the brain that transmits messages.Professor Byard again:ROGER BYARD: This is the control box for heart and for breathing. So if we're looking at these children as having problems controlling their breathing, and then we're finding abnormalities in some of the chemicals that are involved in this process, then this may be one of the direct causes. KATHRYN ROBERTS: What that means is that babies with the condition are not able to detect when they're not getting enough oxygen, so they don't wake up or turn their head.Dr Arthur Teng heads up the Department of Sleep Medicine at Sydney Children's Hospital.He says the research supports the current risk reduction guidelines, which advise parents to put infants to sleep on their back on a firm surface and avoid pre-and post-natal cigarette smoke.ARTHUR TENG: If you look at this new research from Harvard, they postulated that the reason babies die on their side or when they're lying on their tummy is because there is some problem with arousal to get out of what is potentially a noxious situation. And perhaps it's serotonin, which sends the messages to the rest of the brain to wake the child up.KATHRYN ROBERTS: But Dr Teng has some doubts that the research could be used to develop a test for babies.ARTHUR TENG: From what I can understand, the test's a very invasive test, and obviously it would be very hard to screen all babies. I guess the way to look at this is to tap their spinal fluid and measure the levels here. And the gold standard would be a brain biopsy, but I think that would be an extremely difficult to carry out in otherwise normal babies.KATHRYN ROBERTS: Professor Byard however is more optimistic. He says the next challenge is to work out how to detect these abnormalities and the symptoms, which may be evident in infants at risk of SIDS.ROGER BYARD: What they're doing is they're looking at tissue sections from the brain, so you can't do that in live babies. I mean, what people are going to have to do is try and work out whether there's some sort of physiological marker in these babies that indicates a problem with serotonin.And people do that. They've studied heart rate and respiratory rate in babies, but I think what this research does particularly is it focuses on that area and that abnormality, and maybe this can direct clinicians who are looking at live babies to think well maybe this is the way we should approach these cases.KATHRYN ROBERTS: The number of cot deaths in Australia has gone down dramatically - from 500 in 1989, to 59 in 2004.The research gives at least some hope that in the future that number can be reduced even further.MARK COLVIN: Kathryn Roberts.