A baby’s hearing can be tested as early as the first day of life.
The Joint Committee on Infant Hearing (JCIH), which comprises of a team of health professionals, recommends a 1-3-6 protocol. This means that hearing screening should be completed by 1 month of age, hearing loss diagnosed by 3 months of age and intervention be no later than 6 months.
Yes, ideally every newborn should have his / her hearing tested.
Although estimates vary slightly, prevalence figures for hearing loss in children (from the Centers for Disease Control and Prevention-CDC and National Institute on Deafness and Other Communication Disorders – NIDCD) indicate that 1 to 3 infants out of every 1000 will have some degree of permanent hearing loss. It is expected that 10/1000 infants from the NICU will be identified with hearing loss, whereas 1/1000 are expected from the well baby nursery.
Newborn hearing testing is necessary to determine if a baby has hearing loss. This cannot be diagnosed just by looking at the baby’s outer ear and eardrums. Specific tests are available to test hearing. The earlier the diagnosis is made, the earlier can something be done to help the baby hear.
A child can develop language and speech only if he/she can hear well. Research shows that access to sound in the first 6 months of life is crucial for the development of the hearing center in the brain. Exposure to sounds in the early months of a child’s life facilitates language development and promotes growth of neural connections between the brain and the ears. If the child is deprived of this listening experience to build up language and thereby speech, the hearing centers in the brain gradually shut down and the child fails to acquire language and speech. This is why individuals with hearing loss, who are not aided efficiently, cannot speak.
Newborn hearing screening, followed by appropriate detailed hearing testing, and early intervention, in case a hearing loss is detected, can help your baby be a part of mainstream society at par with his / her hearing peers.
It is expected that 10/1000 infants from the NICU will be identified with hearing loss. Social factors such as consanguineous marriages may also increase the risk of hearing loss in a newborn. At times, although the baby may have passed the initial screening tests, they may still develop delayed onset hearing loss in the presence of high-risk factors. Some of the high-risk factors associated with hearing loss are (Source: Year 2007 Position Statement: Principles and Guidelines for Early Hearing Detection and Intervention Programs):
- Family history of permanent childhood hearing loss.
- Neonatal intensive care of more than 5 days or any of the following regardless of length of stay: ECMO assisted ventilation, exposure to ototoxic medications (gentamycin and tobramycin) or loop diuretics (furosemide/Lasix), and hyperbilirubinemia that requires exchange transfusion.
- Infections during pregnancy, such as CMV, herpes, rubella, syphilis, and toxoplasmosis.
- Craniofacial anomalies, including those that involve the pinna, ear canal, ear tags, ear pits, and temporal bone anomalies.
- Physical findings, such as white forelock, that are associated with a syndrome known to include a sensorineural or permanent conductive hearing loss.
- Syndromes associated with hearing loss or progressive or late-onset hearing loss, such as neurofibromatosis, osteopetrosis, and Usher, Waardenburg, Alport, Pendred, and Jervell and Lange-Nielson syndromes.
- Neurodegenerative disorders, such as Hunter syndrome, or sensory motor neuropathies, such as Friedreich ataxia and Charcot-Marie-Tooth syndrome.
- Culture-positive postnatal infections associated with sensorineural hearing loss, including confirmed bacterial and viral (especially herpes viruses and varicella) meningitis.
- Head trauma, especially basal skull/temporal bone fracture that requires hospitalization.
My baby is a healthy normal newborn. My pregnancy and delivery was normal too, with no risk factors. Should I still test my baby’s hearing?
Yes, ideally every newborn should undergo hearing screening. Although estimates vary slightly, prevalence figures for hearing loss in children (from the CDC and NIDCD) indicate that 1 to 3 infants out of every 1000 will have some degree of permanent hearing loss. It is expected that 10/1000 infants from the NICU will be identified with hearing loss, whereas 1/1000 are expected from the well baby nursery (normal newborns).
Otoacoustic emission (OAE) testing and automated ABR (Auditory brainstem responses) are the commonly employed tests for newborn hearing screening. These are simple, quick, non-invasive tests taking about 30 seconds to 30 minutes, depending upon whether a baby is sleeping soundly or moving about. If a baby has any high risk factors present, an automated ABR should be done alongwith OAE. If a baby is from a well-baby nursery then only an OAE would suffice for initial screening.
The results following a newborn hearing screening are “PASS” or “REFER”. “PASS” means your baby has normal hearing at the time of testing. “REFER” means further detailed testing is required, as the baby may possibly have a hearing loss.
If your baby has a “REFER” on an initial hearing screening, re-screening should be done no later than 1 month. Both the ears should be tested separately at the rescreening, even if only one ear has shown a “REFER” at the initial screening. Your baby needs to undergo detailed audiological evaluation. This would include tests such as a BERA (ABR), behavioral audiometry, repeat OAE, etc. to confirm if the baby has hearing loss.
A detailed audiological evaluation by a well-trained audiologist will help confirm if the baby has hearing loss. This should be done as soon as hearing loss is suspected, so that the hearing loss is diagnosed early and the child can have access to hearing aids or a cochlear implant as early as possible. Ideally, hearing loss, if suspected, should be diagnosed by atleast 3 months of age.
If the answers to any of the following is “yes”, your child needs to undergo a detailed audiological evaluation:
- Your baby has a “REFER” result on hearing screening.
- Your baby is not reacting to sounds around the house or is not speaking when he / she should be.
- There is a family history of hearing loss
- The child has an overall developmental delay or there is a presence of high risk factors
- Your baby is not babbling by 6 months or you have observed a decrease in babbling
- Your baby is inconsistently responding to sounds or you suspect that the baby has hearing loss
It is best to get your child’s hearing tested by an audiologist.
Informal tests do not give an accurate measure about the exact degree of hearing loss. Milder degrees of hearing loss may be missed out on such testing. Also, these tests do not check the hearing in each ear individually. At times, the child may be responding to visual movement in his / her field of vision (which you may not realize), or to the vibration that accompanies the sound and this may be mistaken for the child’s response to sound. It is therefore best that you go to a person well-trained in testing a child’s hearing at the slightest suspicion of hearing loss.
A battery of different tests is usually employed to test a child’s hearing. The diagnosis of hearing loss is based upon the results obtained from multiple tests, which are complementary to each other, and not from a single test. Multiple visits to the audiologist may be necessary to complete the entire audiological evaluation. The child’s and family’s history is recorded, evaluation of risk factors for congenital hearing loss is done, and an assessment of parental report of the infant’s responses to sound is performed before proceeding with the test battery. Some of the tests that may be used in different age groups are as follows:
Birth to 6 Months of Age
- ABR (BERA): Frequency – specific assessment using air-conducted tone bursts and bone conducted tone bursts, when indicated. A frequency-specific ABR testing is needed to determine the degree and configuration of hearing loss in each ear for fitting hearing aids when a permanent hearing loss is detected.Click-evoked ABR testing is used, if there are risk indicators for neural hearing loss (auditory neuropathy/auditory dyssynchrony) such as hyperbilirubinemia or hypoxia. Any infant who demonstrates “no response” on ABR elicited by tone-burst stimuli must be evaluated by a click-evoked ABR.
- Distortion product or transient evoked Otoacoustic Emissions (OAEs).
- Behavioral Observation audiometry (BOA)
- Behavioral observation alone is not adequate for determining whether hearing loss is present in this age group, and it is not adequate for hearing aid fitting.
6 to 36 Months of Age
- Behavioral audiometry (Visual reinforcement or conditioned-play audiometry, depending on the child’s developmental level), including pure-tone audiometry across the frequency range for each ear and speech-detection and -recognition measures.
- OAE testing.
- Acoustic immittance measures (tympanometry and acoustic reflex thresholds).
- ABR (BERA): If responses to behavioral audiometry are not reliable or if ABR testing has not been performed in the past.
Testing is easier in older children. A pure tone audiometry is usually done in children above the age of 3 years. The ENT surgeon / audiologist may recommend additional tests on a case- to -case basis.
A 4 –year old should ideally have a well –developed vocabulary and should be able to converse easily with complete sentences. If he /she is unable to do so, you need to first get a complete audiological evaluation done to find out if hearing loss is the cause for delayed speech.
A pure tone audiogram will determine the degree and the type of hearing loss that a person has. In addition to a pure tone audiogram, speech audiometry may be performed in some patients. If a person is already using hearing aids, an aided audiogram (pure tone audiogram with the hearing aid) and a speech discrimination testing is also performed to determine how much benefit the person receives with the hearing aid.
My child has been diagnosed with severe to profound sensorineural hearing loss in both ears. What options does my child have ?
You child should be evaluated by an ENT doctor. The child will need a hearing aid trial in both the ears for a period of about 3 months along with therapy. If the child does not receive adequate benefit even with optimally fitted hearing aids, he / she may be a candidate for a cochlear implant. A high resolution CT scan of the temporal bone and an MRI of the brain with 7th – 8th nerve complexes is also required to check the structure of the ear and hearing nerves. The cochlear implant team can guide you with further details regarding this.
I am 65 years old and have been using hearing aids for the last 10 years. However, now I find it difficult to hear and distinguish between words. What should I do?
You need to undergo a thorough audiological examination. An unaided (without hearing aids) and aided pure tone audiogram should be done. In addition to this, you should also get a speech discrimination testing done. Depending on the results of the tests, the cochlear implant team could decide whether you would be a likely candidate for a cochlear implant.
Upto what age can a cochlear implant surgery be done in an adult who had good hearing earlier in life (post-lingual)?
There is no upper age limit for a cochlear implant surgery in post-lingual patients, provided there are no other medical or surgical contraindications.
Once candidacy for a cochlear implant is confirmed, certain blood and radiological investigations are necessary for anesthesia fitness. Also, children need to be vaccinated against pneumococcus, meningococcus, and H.influenzae at least 4 weeks prior to surgery. The cochlear implant team will provide detailed guidance regarding this.
A day’s stay in the hospital is required for a cochlear implant surgery. It can be done as a day-care procedure.
No. Following surgery, the implant is “switched-on” after about 2-3 weeks (once the wound behind the ear heals). “Switch-on” involves fitting the external processor on the ear and the first programming session (mapping) of the device.
Children born with a hearing loss, who have never been exposed to sound, will not be able to assign any meaning to the sound they hear at first. So, at “switch-on”, the child’s hearing is similar to that of a one-day old baby. A child who has undergone a cochlear implant surgery will need to undergo a structured ‘habilitation’ program i.e sessions with a therapist / habilitationist who will teach the child to understand the meaning of the sounds that the child can now hear. In addition to this the device will also have to be “mapped” (programmed) intermittently by the child’s audiologist.
In adults, or in children who have already acquired language and speech, but who have lost hearing due to age-related degeneration, meningitis or have had progressive hearing loss, the habilitation period is shorter. But they will still require some amount of training to re-learn the sound stimulation that the implant provides.
Mapping and habilitation sessions are required following surgery. Money may also have to be spent for batteries and wires or other parts of the device, in case of damage. Although the internal device does not need to be changed unless the device fails, the companies may launch upgrades to the external devices. You may have to spend money on the upgrades if you have to opt for one.
Stem cell research for hearing loss is still in nascent stages. The trials that are on are still being performed only in animals. The safety and efficacy of using stem cells in humans has still not been proven. Please talk to your ENT doctor before going in for any other alternative modalities of treatment.