Study: Infant Hearing Tests Could Predict Sudden Infant Death Syndrome (SIDS)

Sudden Infant Death Syndrome (SIDS) has long perplexed the medical community. It has left behind a landscape of grieving parents who have little answers. If only there was a way to predict which baby would succumb to this silent killer, there might be hope in preventing it. According to a study that will be published this month by Dr. Daniel D. Rubens of Children's Hospital and Regional Medical Center in Seattle, that soon might be a reality.

The study in Early Human Development has found an interesting link. The study used medical records and hearing tests from 31 babies who had died of SIDS in the state of Rhode Island and carefully compared them with healthy babies. The SIDS babies had different test results for their right inner ears when compared to normal infants who have not died of SIDS. These results are exciting because it could lead to an easy and inexpensive way to identify infants who are at extremely high risk of dying of SIDS.

Also referred to as "crib death" and "cot death" there have been many theories as to why an infant who appears normal suddenly dies for no particular reason. It generally strikes babies from two to four months old and is more prevalent in boys than in girls. 1 in 1,000 babies across the world die from this mysterious syndrome, which makes it the number one cause of death in young babies. In the United States from 1992-1999 there were approximately 3,600 infant deaths that were deemed caused by SIDS, according to an April 2004 article in Archives of Pediatric and Adolescent Medicine.

With Sudden Infant Death Syndrome, the baby dies while sleeping with no warning or noticeable symptoms. With the "Back To Sleep" program, doctors advise parents to lay their babies down on their backs for sleep and do not recommend stomach sleeping. In addition, education and awareness have increased in regards to secondhand smoke and its dangers. There have been hypotheses from infant overheating to a malfunction in respiratory control, but none of them have been proven.

The differences that Dr. Rubens found always occurred in the right ear with a four point lower score on the standard newborn hearing tests, across three different sound frequencies compared to healthy infants, according to the press release. Another interesting observation is that healthy babies usually test with a stronger right ear than the left, but the SIDS babies were exactly reversed with stronger left ear hearing.

"This discovery opens a whole new line of inquiry into SIDS research," said Rubens in the press release. "For the first time, it's now possible that with a simple, standard hearing test babies could be identified as at risk for SIDS, allowing preventative measures to be implemented in advance of a tragic event." He urges further research, adding, "We must now fully explore all aspects of inner ear function and SIDS, and analyze testing frequencies higher than those currently tested by newborn hearing screen centers."

SOURCE:

Children's Hospital and Medical Regional Center in Seattle, WA. Press Release. URL: (http://www.seattlechildrens.org/home/about_childrens/press_releases/2007/07/002259.asp)

Michael H. Malloy, M.D. and Daniel H. Freeman, Ph.D. "Age at Death, Season, and Day of Death as Indicators of the Effect of the Back to Sleep Program on Sudden Infant Death Syndrome in the United States, 1992-1999." URL: (http://archpedi.ama-assn.org/cgi/content/full/158/4/359)