Studies conducted in developed countries have shown that hearing loss is the most common birth defect with an incidence rate of 3 for every 1,000 babies born every year.
A newborn cannot communicate with the parent, making it difficult for the doctor or parent to identify the defect early on. Babies who do not hear your voice, a lullaby or a nursery rhyme may have problems learning to talk.
It is important to have your baby’s hearing tested before you leave the hospital after delivering the child. Hearing problems need to be identified as early as possible so that you may take the necessary actions that give your baby the best chance to develop speech and language.
Hearing loss is a hidden disability — that’s why it is so important to have your baby’s hearing tested. Each year, more than 4,000 babies are born with hearing loss. Most babies born with hearing problems are otherwise healthy and have no family history of hearing loss.
It is important for you to be sure that your baby has normal hearing. The first year of life is critical to the development of normal speech and language.
Newborn hearing screening is a simple method of checking if a baby’s hearing is intact. It is performed with the use of sophisticated instruments that will not affect the baby.
Good hearing is essential to the social and intellectual development of infants and young children. Audiologists can identify hearing loss in children of any age.
The Joint Committee on Infant Hearing, October 2007 and US Public Health Services Healthy People 2010 health objectives recommend that all newborns:
Be screened for hearing loss within the first month
Have diagnostic hearing testing to ascertain the degree and type of loss within 3 months,
Enrol in an appropriate intervention programme by six months of age (known as the 1-3-6 protocol).
The following are guidelines for development and answers to common questions.
How will my baby’s hearing test be done?
There are two types of hearing screening tests that may be used with your baby. Both tests are safe and it takes only minutes to evaluate each ear. Most babies sleep through their hearing screening.
Otoacoustic Emissions (OAE) are measured directly with a miniature microphone and sent to a special computer to determine your baby’s hearing status. It tests the outer hair function of the cochlea.
Normal hair cells create an emission in response to tone. Presence of the emission is consistent with the normal outer hair cell function. When outer hair cell function is normal the child’s ear is interpreted as functioning normally. If the OAE is absent or abnormal then a further test, namely the ABR, is required.
Auditory Brainstem Response (ABR) tests the infant’s ability to hear soft sounds through miniature earphones. The click stimulus, usually at 35 dbHL, is delivered to the infant’s ear via small ear phones. A pass or refer response is determined. It can be used us an effective tool for screening infants younger than 6 months.
In the follow-up testing, a further diagnostic ABR can be used to determine the degree of hearing loss and also the nature of the hearing loss.
What if my baby does not pass the test?
There are many reasons your baby may not ‘pass’ the first hearing test and require a second evaluation. Perhaps your baby was too active, too wide-awake, or you were discharged from the hospital before the hearing test was completed. It is important that you follow through with any recommendations made by your audiologist, ENT and/or physician.
If my baby passes the screening, do I need to have hearing checked again?
Hearing screening tests usually confirm that your baby has normal hearing. However, hearing problems in your baby can develop after you leave the hospital.
If anyone in your family has hearing loss, your baby should be tested every year. If you ever have concerns about your child’s hearing, speech or language, be sure to discuss them with your audiologist and/or physician.
Intervention
If hearing loss is confirmed, an intervention programme should be planned at the earliest with the involvement of an audiologist and the speech therapist. If the intervention process is started within the first year of life, a remarkable difference can be made in the quality of speech and hearing.
Some of the intervention processes used currently are hearing aids and cochlear implants along with speech therapy and auditory training.
(The author is Audiologist and Director, Rajan Speech and Hearing Centre.)