By:  Dr. Ruth Reisman

Why Do a Hearing Test on a Newborn?

It is well researched that there is a critical age for speech and language development in children from 0-5 years of age. If significant language milestones are missed during this time period the child is at risk for language impairment, abnormal social development,  and learning difficulties later on in life (Shearer et al, 2019). A child’s inability to hear, whether it’s permanent or transient, will result in inconsistent language stimuli sent to the brain that will inhibit their ability to reinforce the correct neural pathways for normal language development.

Therefore conducting newborn hearing assessments has become a part of a widely accepted screening protocol in newborn care. Laws were passed in 43 states requiring infant hearing screening to be conducted in the newborn nurseries. It is recommended that children are screened by 1 month of age for hearing loss, diagnosed by 3 months, and receive intervention by 6 months for optimal outcomes. Due to the regulations surrounding newborn hearing screening, research shows that 98.2 % of newborns  are now having their hearing screened.

How Do We Test Newborns?

Babies cannot respond to hearing tests like adults do with earphones, therefore objective measures of hearing have been developed to assess the hearing system in newborns. A systematic review of hospital newborn hearing screening protocols found that there is a lack of consistency between testing protocols from facility to facility (Kanji et al, 2018). However, the majority of programs use either transient otoacoustic emissions ( OAE )testing, auditory brainstem response testing, or some combination of the two. 

What do these tests mean and what do they tell us?

Otoacoustic emissions is a physiological assessment of the inner ear. During this test echoes from the sensory organ for hearing are being monitored to determine cochlear function. This test aids in the diagnosis of the degree and type of hearing loss and is especially useful in estimating hearing loss in difficult to test populations like newborns. TE OAE are found to be more sensitive in ruling out up to a mild hearing impairment as compared to DP OAE that can potentially miss up to a moderate hearing loss. Auditory brainstem response testing on the other hand, is a physiological assessment of the auditory nerve and hearing structures within the brainstem. The auditory brainstem response test can aid in the differential diagnosis of cysts or tumors on or within the neural auditory pathway. It is also used to estimate levels of hearing in difficult to test or unreliable patients. Potentials from the auditory pathway are being monitored through superficial electrodes placed on the skin and ears, and with that we can rule out up to a mild hearing loss in newborns.

What Happens if a Newborn Fails the Hearing Screening?

If your newborn doesn't pass the hearing screening on the first try they will typically:
  1. Re-screen prior to discharge. The hospital will either use the same screening method or an alternate screening method to see if it will yield a different result. 
  2. Counsel. If the baby continues to fail prior to discharge the staff will counsel the parents on what a failed hearing screening means. Oftentimes newborns will fail because they have residual birthing fluids in the ear canal. Parents are reassured that this is common but are strongly encouraged to follow up to rule out permanent hearing loss.
  3. Refer. Parents are referred to an audiologists or their pediatrician for a re-screening within one month of discharge.
  4. Follow up. Parents are expected to remain diligent in the follow-up care for their babies' hearing.
  5. Reporting. Hospitals and newborn screening facilities are required to report the results to the state in an effort to track those newborns that fail and require follow-up newborn hearing care.

What Happens if My Baby Still Fails the Hearing test?

Testing newborns is extremely rewarding particularly when we are able to provide reassuring news to the worried new parents that their baby passed the hearing screening and that with regular monitoring everything will likely be ok. But what happens if the baby doesn’t pass?? Counseling parents on a failed hearing screening is one of the most challenging aspects of my job as an Audiologist. Despite reassuring parents that things will likely be fine, you see the growing fear in their eyes with the news of another failed test. They now have to return within 2-4 weeks to do this all over again... and if failed, will require a full hearing evaluation.

What does a full evaluation look like?

Babies cannot provide subjective responses like older children and adults therefore objective measures need to be used. The two methods used to measure infant hearing are the auditory brainstem response threshold test or the Auditory Steady State Response (ASSR) test that assesses hearing thresholds at .5, 1,2 and 4 kHz simultaneously. These assessments are objective measurements of the hearing nerve that will be translated into hearing thresholds on an audiogram.

What are the causes of hearing loss in newborns?

There are many causes of hearing loss in Newborns that vary by  degree, configuration, and etiology.  The most common causes of hearing loss in newborns are ear canal fluid, which is often transient, or genetic hearing losses which is typically permanent. Other causes include hearing loss secondary to maternal illness or taking substances during pregnancy that were unknowingly ototoxic. The majority of mothers are unaware that self medicating could potentially pose risks to their unborn fetus (Jato et al, 2018).

What can be done? What parents should know.

Early intervention is critical when caring for newborns with hearing loss. Following the recommended guidelines of rescreening at 1 month, diagnosing by 3 months, and intervention by 6 months will give the child the best chance at normal speech, language,  and behavioral development. There are times when the hearing loss can be treated with medication or surgery and other times when children will need hearing devices as well as speech therapy to ensure their success. There are many resources for parents of children with hearing loss including support groups and paid services under Early Intervention (EI) Program. Parents should ask their pediatrician or Audiologist for a referral to the local EI service provider.

What professionals should know

Diagnosing a newborn with hearing loss can be challenging particularly dealing with the parents emotions:
  1. Shock
    • Anger, panic, loss
  2. Realization
    • Understanding that situation will not change
    • Leads to anxiety, lack of sleep, depression, lack of compliance with recommendations
  3. Retreat
    • Want to run away from the situation
    • Non-compliant with therapy goals
  4. Acknowledgement
    • Accept that the disability is there
    • Often viewed as a religious punishment (negative) or a challenge to rise above (positive)
  5. Guilt
    • Parent can feel responsible for the disability
    • Leads to over loving/ overprotecting
    • Withdrawal 

What’s the Goal??

The goal is to get the family to process the  emotions so their child receives services with minimal time delay due to the critical age for speech and language development from. Providing support, resources and information to parents will help them to process their emotions and get their child and the Newborn care they will need.
References
 
Mercy E. Jatto1 , Segun A. Ogunkeyede1, 2, Adebolajo A. Adeyemo,1, 3 Kazeem Adeagbo1 and Orinami Saiki1 Ghana. Mothers’ perspectives of newborn hearing screening programme. Med J 2018; 52(3): 158-162 doi: http://dx.doi.org/10.4314/gmj.v52i3.9
 
Amisha Kanji, Katijah Khoza-Shangase, Nomfundo Monroe,
Newborn hearing screening protocols and their outcomes: A systematic review,
International Journal of Pediatric Otorhinolaryngology, Volume 115, 2018, Pages 104-109, ISSN 0165-5876, https://doi.org/10.1016/j.ijporl.2018.09.026.

Shearer, A.E., Shen, J., Amr, S. et al. A proposal for comprehensive newborn hearing screening to improve identification of deaf and hard-of-hearing children. Genet Med 21, 2614–2630 (2019). https://doi.org/10.1038/s41436-019-0563-5
The information contained in this article is for educational and informational purposes only. You should not use the information as a substitute for, nor should it replace, professional medical advice. If you have any questions about your health, you should always consult with a physician or other health-care professional.