sids inner ear

Seattle Doc Launches Study to Investigate Link Between SIDS and Inner Ear

SEATTLE, WASHINGTON — Seattle Children’s anesthesiologist, Dr. Daniel Rubens, has been researching Sudden Infant Death Syndrome (SIDS) since 2002 and hopes that the launch of his new study will eventually lead to a means of preventing the mysterious condition that results in the death of thousands of seemingly healthy children each year in the US.

As reported last year by David Kirkwood at Hearing News Watch, Dr. Rubens has gained national attention with his theory that a hearing abnormality, detectable by newborn hearing screening, could be a warning sign of SIDS.

For the new two-year study, launched this month entitled “Oto-Acoustic Signals in SIDS”,  he has partnered with Dr. Peter Fleming of Bristol University and The Lullaby Trust in the UK. Much of the $150,000 raised for the study, has come from families that have lost children to SIDS.

Mysterious Condition

 

Dr.Daniel Rubens
Dr. Daniel Rubens

Although the root cause of SIDS remains unknown, it has long been suspected that some disturbance in the respiratory control system plays a significant role. Research has also shown the vestibular system plays an important part in respiratory control during sleep.

A possible link between abnormalities in the inner ears of newborns and SIDS were first published by Rubens and colleagues in a 2007 study in the journal Early Human Development. Analyzing data from the Rhode Island Department of Health Infant Mortality Database for 31 babies born between 1993 and 2005 who had undergone newborn hearing screening and then died of SIDS.

In all 31 cases, hearing screening using TEOAE (transient evoked otoacoustic emissions) testing showed significantly decreased signal-to-noise ratios at 2000, 3000, and 4000 Hz (p < 0.05) on the right side compared to the controls.

 

After analyzing the data, Rubens et al. explained in their 2007 article: “We hypothesized that an inner ear insult resulting in disruption of vestibular function might play a critical role in the predisposition for SIDS.”

 

Rubens believes that reduced hearing levels among the Rhode Island newborns who later died of SIDS were symptomatic of damaged vestibular cells in the right ear. Vestibular cells not only work to maintain balance, but also play a role in transmitting information that regulates a baby’s breathing and arouses a baby who is exposed to a suffocating environment. If those vestibular cells are not functioning properly, they will not arouse a sleeping baby who has moved into a position where breathing is restricted. Sadly, as a result, the child may suffocate.

 

Hearing Screening to Determine SIDS Risk?

 

Because of the risk of false positives and false negatives, there is much more research needed before a hearing screening specifically for SIDS could be developed. However, if the data collected during this latest study is consistent with the earlier and smaller Rhode Island study from 2007, Rubens and his colleagues believe this could lead to large-scale institutional funding.

Potentially, a risk scoring system for SIDS could be developed that would combine a hearing screening exam with a comprehensive risk factor assessment at birth.

 

Source: Puget Sound Business Journal; Images courtesy Seattle Times