New SIDS Research: Physiological Evidence Found

In recent news out of Children's Hospital Boston, there is new evidence in support of a physiological basis for Sudden Infant Death Syndrome (SIDS). Researchers have found evidence that babies who die from SIDS have similar abnormalities in their brainstems.

SIDS is the leading cause of death among infants who are 1 month to 1 year old. The syndrome is believed to claim the lives of about 2,500 infants each year in the United States. (KidsHealth.org) Solid evidence about what causes SIDS, and about how to predict whether an infant is at risk for it has remained illusive, despite many years of medical research.

The evidence discovered by the Children's Hospital Boston team could prove groundbreaking in the quest to protect children and their families from SIDS. In the new study, the presence of physiological abnormalities in the brainstems of the infants who had died from SIDS may help to provide medicine with a direction

A research paper on the study was published in the November 1, 2006 issue of The Journal of the American Medical Association. The brainstem tissue of 41 infants- 31 who had died from SIDS, and of 10 who had dies of other causes had been analyzed, and the research team discovered that the infants who had died of SIDS had an abnormally high number of serotonergic neurons- the nerve cells that make and release serotonin, one of the messaging chemicals found in the brain- but these serotonergic neurons were found to be underdeveloped more often than those found in the brainstems of babies who had died of causes other than SIDS.

"Our hypothesis right now is that we're seeing a compensation mechanism," said David Paterson, PhD, a researcher at Children's Hospital in Boston who is the lead author of the research paper. "If you have more serotonin neurons, it may be because you have less serotonin and more neurons are recruited to produce and use serotonin to correct this deficiency." (National Institutes of Health)

Also discovered in the brainstems of the infants who had died from SIDS was a deficiency in a specific serotonin receptor and in a protein involved in the serotonin recycling process, according to the researchers.

Serotonin plays a role in regulating vital functions like arousal, breathing and blood pressure.

"This finding lends credence to the view that SIDS risk may greatly increase when an underlying predisposition combines with an environmental risk - such as sleeping face down - at a developmentally sensitive time in early life," said Duane Alexander, M.D., Director of the NIH's National Institute of Child Health and Human Development. (National Institutes of Health)

The researchers also found that in male SIDS infants, the serotonin receptors were considerably fewer than in female SIDS infants, possibly explaining why SIDS strikes boys twice as often as girls.