Dr Daniel D Rubens and colleagues at the Children’s Hospital and Regional Medical Center in Seattle, analyzed data on 31 Rhode Island babies who died of SIDS. They found that they all shared the same distinctive difference in newborn hearing test results for the right inner ear.
Compared with other babies, those who died of SIDS scored four points lower in standard newborn hearing tests, across three different sound frequencies in the right ear.
Rubens also noted that healthy infants typically test stronger in the right ear than in the left. However, the infants who died of SIDS had lower scores for the right ear than the left.
“This discovery opens a whole new line of inquiry into SIDS research,” Rubens said in a prepared statement. “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.”
The inner ear contains tiny hairs involved with both hearing and vestibular (balance) function. Vestibular hair cells may play an important role in transmitting information to the brain about levels of carbon dioxide in the blood, Rubens suggested. Injury to vestibular hair cells may disrupt respiratory control and predispose infants to SIDS.
Rubens urged further research in this area. “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,” he said.
SIDS kills about one in 1,000 infants worldwide. Most of the victims are between 2 to 4 months old, with boys more likely than girls to die of SIDS.