However, she thinks Dr. Rubens’ research warrants further study. I think the study is interesting and merits further investigation, she said. I doubt that the cochlea or vestibular systems regulate respiratory drive, but the difference in TEOAE thresholds may indicate a concomitant difference in central processing in the respiratory centers located in the brainstem. Such a difference may explain the lack of appropriate arousal response in these infants.
Explore This IssueApril 2008
A current study under way by Dr. Rubens that is looking at the breathing response to carbon dioxide in infant mice with cochlear and vestibular damage would provide stronger evidence for his theory.
Feasibility of a Hearing Screening Test
If the evidence holds up with further study, creating a hearing test to identify infants at risk will be possible. Many hospitals already undertake routine hearing screening tests, said Dr. Manning. If we had a practical test that could also test higher frequencies, which are more sensitive to damage, then the test might be more sensitive for predicting SIDS.
For Dr. Rubens, the current routine use of screening hearing tests for infants in the United States is seen as a real opportunity to identify infants at risk for SIDS. We are looking at undertaking larger-scale studies that hopefully will, in the not too distant future, show us what that hearing test will look like, he said, adding that we have our work cut out to do that.
For Dr. Bauman, however, even if such a hearing test were available to identify infants at risk, its use would be welcomed but would present potential difficulties. I would suspect that the specificity of the test would likely be very low, indicating that many infants with a difference in signal-to-noise ratio levels would be identified but very few would actually be at risk of SIDS, she said. The management of all these infants, and their very concerned parents, would be difficult, as apnea monitors have not been found useful in the prevention of SIDS.
Dr. Rubens hypothesizes that SIDS results from a disruption in vestibular function caused by an injury to the inner ear and brainstem during the birthing process.
Dr. Rubens suggests that a well-validated hearing test will, in fact, afford the majority of parents peace of mind after their baby is born by freeing them from the worry that their child could be predisposed to SIDS. Every parent in the world currently does worry that their infant may be prone to SIDS, and there is no relief until the infant passes the risk period at one year of age. A well-validated hearing test would offer peace ahead of time that there is little cause for concern, he said. For those infants that may be shown to be susceptible to SIDS, this will offer the opportunity ahead of time to monitor the infant and implement preventive measures for the first time.