(CBS) A mysterious condition called Sudden Infant Death Syndrome, or SIDS, is a nightmare possibility for new parents. Despite a steady decline for more than a decade, thousands of babies die in their sleep every year for no apparent reason: More than 2,200 deaths were reported in 2004.

Dr. Jon LaPook has more on a new study which says a common test could indicate which babies may be at risk of Sudden Infant Death Syndrome.

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"I'm hopeful that we're definitely closer to making SIDS something of the past," says Dr. Daniel Rubens of the Seattle Children's Hospital Research Institute.

Rubens, the lead author of a new study examining 31 cases of SIDS, has discovered a previously unsuspected connection.

"We've found for the first time that there's something going on in the hearing of SIDS babies," he says. "This is totally new and we've never had this before."

His study found that the group of newborns who later died from SIDS shared the same hearing tests results. The scores, reflecting inner ear function, were significantly lower in the right ear than in the left, something not usually seen in healthy infants.

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Learn More About The SIDS Study

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"I'm suggesting that the inner ear plays a key role in the control of breathing," says Rubens.

Rubens' theory is that damage to the inner ear, possibly occurring at birth, can fatally impair a child's ability to breathe normally.

SIDS researcher Dr. Henry Krous, of the Children’s Hospital of San Diego, calls the study provocative but preliminary. He says parents should continue to follow the steps already proven to reduce the risk of losing a child to SIDS.

"Put babies on firm surfaces for sleeping," he advises. "They should be placed on their back, they should not be overly swaddled."

The study does not mean there's a hearing test that can predict SIDS. But because hearing tests are already being done routinely on most babies, the opportunity may exist to follow a large number of children from birth to see if SIDS can be predicted — and maybe prevented.

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