By : Meenakshi Chanu
NBS Centre RIMS Imphal
Hearing loss is one of the most common congenital anomalies, occurring in approximately 2-4 infants per 1000. Detection of hearing loss in newborns are very important to help their speech language, learning and social development. This is necessary for the children as well as their families and society. So, reliable screening tests that minimize referral rates and maximize sensitivity and specificity are essential.
Newborn Screening for communication Disorder is a program of screening hearing/testing hearing sensitivity carried out in all the newborns soon after their birth for identification of at risk babies for communication disorder. The screening program are conducted by the Department of Prevention ofCommunication Disorder (POCD) at the All India Institute of Speech and Hearing (AIISH) Mysuru. AIISH Mysuru under the Ministry of Health and Family Welfare had launched this project in six centre of India i.e Cuttack, Ajmer, Imphal, Ranchi, Jabalpur and Puducherry. Newborn screening program started in RIMS, Imphal in collaboration with AIISH from the year2012.
The program is focussed on newborn baby other than children and adults to make early detection/identification and intervention of speech and hearing disorder leading to accomplish good communication skills and better quality of life. Early identification and intervention make the utilization of critical period for development of speech and language skills.
The hearing of newborn can affects by various causes
Prenatal causes (before birth): late pregnancy, ototoxic medication, alcohol, medication, alcohol, cigarette, viral/bacterial infection, Rh incompatibility, TORCH.
Natal causes (at the time ofbirth): low birth weight, delayed birth cry, absent birth cry, lack of oxygen supply, hypoxia, Asphyxia, premature, post mature delivery, neonatal jaundice, Hyperbilirubinemia, aspiration of amniotic fluid.
Post Natal causes (after birth): craniofacial structural abnormalities (CLP), congenital condition, convulsions, fits, trauma of head and neck. Young children can lose their hearing after they get some illnesses, including meningitis, encephalitis, TORCH, measles, chickenpox and flu. Head injuries and exposure to very loud noise and some medications can also cause hearing loss.
Aims and objective of Newborn Screening program (NBS)
1. Prevention of hearing loss in newborns
2. Early identification
Programs of NBS
· Awareness program
· Orientation program
· Hearing screening and school screening camps
· Outreach and Extension services
Types of hearing loss
1. Conductive hearing loss
2. Mixed hearing loss
3. Sensorineural hearing loss
Conductive hearing loss occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones (ossicles) of the middle ear. It occurs in newborns o r children with abnormality or deformity in the structure of outer ear canal. Otitis media is also one of the most frequently diagnosed diseases in infants and young children. The condition can be temporary or permanent and can occur in one or both ears. More commonly, it begins during childhood as the result of middle ear infections. This type of hearing loss present in children with Downs syndrome also.
Sensorineural hearing loss involves problems with the transmission of sound information from hair cells deep within the ear to the nerve that sends sound information to the brain. It is a permanent condition that usually affects both ears. This can be present at birth or it can occur if there is a family history of deafness or the cause is likely to be inherited (genetic). If the mother had rubella (German measles), cytomegalovirus (CMV), or another infectious illness that affects hearing during pregnancy, the fetus could have been infected and may lose hearing as a result.
Mixed hearing loss is both presence of both conductive and sensorineural.
General identification measures: it can be identify by parent, caregivers who are familiar with baby in their daily living activities. It is often difficult to detect, especially in young children. Following are typical developmental milestones in children with normal hearing. Babies and young children with hearing loss will not achieve these milestons:
Infant’s Age Arousal from sleep for 90 dB SPL
3-4 months Rudimentary head turn for normal conversation
4-7 months Localization to side for soft sounds (40-50 dB SPL)
7-9 months Localizes to side and in-directly below for a loud whisper (30-40 dB SPL)
9-13 months Localizes to side and below a loud
whisper (30-40 dB SPL)
16-16 months Localizes to side, below and indirectly above
to soft sounds
16-21 months Localizes directly to the side, below and
above to a whisper
21-24 months Locates directly a sound at any angle to soft sounds.
Medical indications are Ear discharge, Ear pain, Irritation or itching in the ear.
Behavioural indications include
· Inconsistent responses to sound
· Does not speak or imitate sound
· Language and speech development is delayed
· Speech is unclear
· Does not follow directions
· Child does not respond when called
· Use of more actions and signs
· Pulling or scratching at the ears
· Play the TV or radio too loudly
· Poor academic performance
· May relies more on speech reading (lip reading)
HRR (high risk register)
This group included infants whose mothers suffered from illness during pregnancy, those who had a family history of hearing loss, or those who were exposed to drugs known to affect hearing. In addition, infants with the following conditions were included for hearing screening:
· Low birth weight, prematurity, oxygen deprivation or breathing difficulties at birth
· Syndromes associated with hearing loss (Down’s syndrome, Turner syndrome)
· Abnormal head or face structures
· Infections such as TORCH (Toxoplasmosis, other Rubella, cytomegalovirus, syphilis herpes)
· Low Apgar scores (which assess several health factors at one and again at five minutes after birth).
HEARING SCREENING PROTOCAL
· BOA (Behavioral Observation Audiometry) checks the infants response to sound stimuli.
· OAE (Otoacoustic emission) This is a relatively quick and non-invasive test. A miniature microphone is placed in the ear. It picks up signals that normally are emitted from the hair cells in the inner ear. This is an excellent screening test for all newborns. If a hearing problem is found, it should be confirmed with the Auditory Brainstem Response test. (ABR/BERA). OAE is of two type : Screening and diagnostic tests
Screening tests – Pass/Refer
Diagnostic tests – Detailed evaluation
· Impedance Audiometry : Test to rule out middle ear problems. It measures the air pressure in the middle ear and the ability of the eardrum to move.
· ABR (Auditory Brainstem Response or BERA (Brainstem Evoked Response Audiometry). In this test, response are obtained from electrical signals passing through nerves involved in hearing. This test is used to screen newborns or to test children unable to cooperate with other methods. Young children often need to be sedated during this test so that their movements don’t interfere with the recording.
Babies who are at risk for hearing loss will undergo follow up OAE and ABR with interval of 3 months. At the age of 6 months, hearing impaired baby can receive intervention for better prognosis and to develop the child like normal peers in relevant to development of speech and language.
Primitive reflexes are reflex actions exhibited from the central nervous system that are shown by normal infants in response to certain stimuli but not by neurologically affected infants. Some of the reflex namely Moro, Rooting, Sucking, Tonic neck, Palmar, Plantar and Babinski reflex. These reflex are checked in association with hearing screening to rule out involvement of neurological disorder in infants.
Conductive hearing loss often can be corrected. For example, middle-ear infections and the associated fluid build up can be treated and the child’s hearing can be monitored. Surgery may be considered for some problems. Another treatment option for severe or profound sensorineural hearing loss is a cochlear implant. This device is surgically implanted in the skull. It helps to translate sound waves into signals that can reach the brain. Cochlear implants are approved in the United States for use in children older than 12 months of age. Children with significant hearing loss also can learn sign language and lip reading to communicate with others.
Thus, the failure to identify and treat hearing loss by 6 months of age can have serious implications for a child’s speech. Even slight hearing loss in one ear can impact a child’s speech and language development. Treating a child before 6 months of age can make a huge difference in language and speech development by taking the advantage of critical period. Early identification and intervention can prevent severe psychosocial, educational and linguistic repercussions. Infants who not identified before 6 months of age have delays in speech and language development. Intervention at or before 6 months of age allows a child with impaired hearing to develop normal speech and language, alongside his or her hearing peers. (Concluded)