Wednesday, August 19, 2009

Deafness is the most common of all birth defects

Source Link - Deafness is the most common of all birth defects

Why do they test baby’s hearing when they are born?

Deafness is the most common of all birth defects. Every day 33 babies in the United States are born with some form of hearing loss. That equates to around 12,000 babies every year. Before we started testing babies in the hospital, the average age at which a baby was diagnosed was 30 months. That is well after language and learning disabilities may have developed.

A study published in the November 1998 issue of Pediatrics compared the speech and reading comprehension skills of children who were diagnosed with a hearing loss before the age of 6 months and those diagnosed later. The children who were diagnosed before the age of six months had significantly better language and reading comprehension skills.

The earlier a hearing loss is identified, the more likely it is that interventions such as hearing aids and cochlear implants can help a child remain in mainstream education programs. A recent study on cochlear implants demonstrated that special education in elementary school is less necessary with children who had greater than two years of implant experience.

According to the National Center for Hearing Assessment and Management, the cost of educating a deaf child through high school is more than $420,000. The same child, if identified at birth and given a $40,000 cochlear implant or a $5,000 hearing aid, can attend mainstream elementary and high school classes. The potential savings for our educational system are apparent with early diagnosis.

In 1990, Hawaii became the first state to pass legislation mandating that all birth facilities do hearing screens on babies. Florida started doing universal hearing screening in 2000.

Testing the babies is just the first step. Florida also had to make sure there was going to be follow-up, intervention, tracking and reporting for those babies who needed it. It was a massive undertaking.

Several hospitals piloted the hearing screening and coordinated follow up for two years prior to the mandated screening began. We, as a state, were able to problem solve and learn from other states how to make our system be effective.

The baby’s hearing is measured by presenting a series of very brief acoustic stimuli to the ear through a probe that is inserted in the outer third of the ear canal. The probe contains a loudspeaker that generates clicks and a microphone that measure how the cochlea responds. The cochlea perceives the motion of sound and turns it into sensory information that can be processed by the brain. The microphone then measures how the sound is then transmitted back through the middle ear.

The resulting sound that is picked up by the microphone is digitized and processed to determine whether the cochlea is functioning properly. Sometimes babies still have vernix (a cream that covers the baby in utero) in their ears. This can influence how well they do with the initial hearing test. If they do not pass the test they are scheduled for a retest in a few weeks.

Katie Powers, R.N., is a board-certified lactation consultant and perinatal educator at Manatee Memorial Hospital’s Family BirthPlace. Her column appears every other week in Healt