Babies who are born deaf
(Importance of early identification of hearing loss)

P. Meenakshi Chanu *

Hearing loss is one of the most common birth defect. Most babies are born with perfect hearing but 2-3 in every 1000 healthy babies are born with hearing loss. Most estimate suggest that 1-3 per 1000 children are born with hearing loss. All parents wants their child to be able to developed their full potential. So, parents will experience a huge range of emotions which discover their child is deaf.

Children relied on their hearing to learn from the beginning. It is crucial to identified any remedy problems as early as possible. With the right treatment, most children with hearing loss hear again and grow up normally if treated early, attending mainstream school (normal school), reading and speaking like peers.

Congenital deafness may be of two causes in children. One is due to lack of hair cells receptors in the inner ear that convert sounds into pulse signals that activate the auditory nerve and the second cause is a malfunction of the nerves. A child may be born with what appears to be a normal inner ear, but the hair cells do not “communicate” with auditory nerves and the child cannot hear.

The Newborn Hearing Screening programs ensure that every child born with a permanent hearing loss may or may not be associated with high risk criteria like absent Birth cry , Neonatal Jaundice, Birth Asphyxia, Premature delivery etc are identified at the time of birth or before three months of age are provided with timely and appropriate intervention services before six months of age.

Obviously, the earlier we can identify hearing loss the sooner we can begin to treat the problem and have better outcomes for that individual.

Two types of newborn hearing screening tests are used: One is Otoacoustic Emissions or OAEs.

In this, a miniature earphone and microphone are placed in the ear which stimulates the outer hair cells and response are reflected back to screen of OAEs instrument whether the response is PASS (Normal) or REFER (abnormal). The second test called the Brainstem Evoked Response Audiometry (BERA) or Auditory Brainstem Response or ABR.

For this test, electrodes are placed on the mastoid of both ear and a ground electrodes on the forehead to detect responses. ABR and is an objective test to understand the transmission of electrical waves from the VIII the cranial nerve to the brainstem, in response to sounds and can identify babies who have a hearing loss.

In some hospitals, babies are first screened using OAEs. Babies who do not pass on the first OAE test can be given a second test using the ABR. Both tests are reliable.

COCHLEAR IMPLANT

Cochlear implants are much different than hearing aids, which only amplify sounds. By contrast, cochlear implants is a surgically implanted electronic device that bypass the hair cells and directly stimulates the auditory nerve. The implant generates signals that are sent to the brain via the auditory nerve. The brain then recognizes these signals as sound.

If the child has severe to profound hearing loss and do not get benefit from any hearing aids, then a cochlear implants could be an effective solution. The younger the child receive a cochlear implant, the easier it will be for them to meet the critical period i.e. the first two year of life that are very important in the development of their crucial language, speech and communication skills.

Children who are fit with appropriate amplification before 6 months can developed language skills on a per with hearing. However, children who receive cochlear implants before 18 months of age are better able to hear, comprehend sound and music, and can speak than their counterparts who receive the implants at a later age. The child who underwent cochlear implant should go for Auditory Verbal Therapy (AVT- a speech and language training approach).

Children who do not received early treatment suffered from language delayed, reading difficulty, delayed in cognitive skills leading to isolation, low self esteem, learning difficulty and behavioral problems.

So, it is very essential for the baby/child is tested, diagnosed and get speech and language therapy with the help of hearing aids, cochlear implants and other treatment to meet development of speech and language milestone at right time.

It is concluded that all infants admitted to the Neonatal Intensive Care Unit (NICU) should be screened for hearing loss prior to discharge, Universal screening to be implemented for all infants within the first 3 months of life, the preferred model for screening should begin with an OAE test and should be followed by a BERA test for all infants who fail the OEA, comprehensive intervention and management programs must be an integral part of a universal screening program and education of primary caregivers and primary health care providers like ASHA (Acredited social health activists) on early signs of hearing impairment is essential.