Congenital hearing loss, or hearing loss that is present at birth, is one of the most prevalent chronic health conditions in children. Some risk factors for hearing loss in newborns include genetics, prematurity, NICU stays, infections (i.e. rubella, CMV, etc.), drug and alcohol abuse while pregnant, jaundice, preeclampsia, birth injuries, and maternal diabetes. In most developed countries, babies have their hearing checked before leaving the hospital or birthing center. Newborn hearing screening programs allow for early identification and early intervention for infants who refer to hearing screenings in the hospital. Early identification and intervention is very important for a child’s overall health and development.
What are signs of hearing loss?
Since newborn babies are not yet able to communicate in the same way older children or adults do, there are signs of hearing loss in babies that parents can watch for. Some of the signs include not startling from loud sounds, not localizing or turning toward a sound (after 6 months), unclear or delayed speech, and hearing some sounds but not others.
It is important to remember that children respond differently at different stages of development; however, not every child is the same and reaches milestones at different ages. Below are some age-related milestones that may help parents identify if their child has a potential hearing problem.
Birth to 3 months:
- Reacts to loud sounds with startle reflex
- Is soothed and quiet by soft sounds
- Turns head to those speaking
- Wakes up when there are loud voices/sounds
- Smiles in response to certain voices when spoken to
- Seems to know parents’ voice and quiets down if crying
4 months to 6 months:
- Looks or turns toward a new sound
- Responds to “no” and changes in tone of voice
- Imitates his/her own voice
- Enjoys rattles and other sound-making toys
- Begins to repeat simple sounds (ex. “Ooh, aah, ba-ba”)
- Gets scared by loud voices/noises
7 months to 12 months:
- Responds to their own name, phone ringing, or someone’s voice, even when not loud
- Knows words for common things and sayings (“cup”, “shoe”, “bye-bye”)
- Makes babbling sounds – even when alone
- Starts to respond to requests (“come here”
- Looks at things or pictures when someone talks about them
- Enjoys games such as peek-a-boo and pat-a-cake
- Imitates simple words and sounds – may use a few single words meaningfully
1 year to 2 years
- Follows 1-step commands when shown by a gesture
- Uses words he/she has learned often
- Uses 2-to-3-word sentences to talk about and ask for things
- Says more words as each month passes
- Points to some body parts when asked
- Understands simple “yes-no” questions
- Understands simple phrases
- Enjoys being read to
- Understands “not now” and “no more”
- Chooses things by size (big, little)
- Follows 2-step commands (“get your shoes on and come here”)
- Understands many action words (run, jump, sing)
What are common types of hearing loss?
The auditory system is the system in our bodies that houses organs for hearing and balance. It develops very early on in-utero and is fully functioning at birth. There are three main parts of the ear – the outer, middle, and inner ear.
- Outer ear: The outer ear includes the external portion of the ear (the pinna), the ear canal, and the outside of the eardrum. The eardrum separates the outer ear from the middle ear.
- Middle ear: The middle ear is made up of the eardrum and three small bones, called the ossicles. The ossicles are some of the smallest bones in the entire body! When we hear sound, it moves through the ear canal and causes the eardrum to vibrate. When the eardrum vibrates, it moves the ossicles, which helps move sound to the inner ear.
- Inner ear: The inner ear contains the cochlea, our hearing organ, and canals that help with balance. The cochlea is snail-shaped and is fluid-filled. The inner ear also houses nerves that change sound vibrations from the middle ear into signals that travel up to the brain through the auditory nerve (or hearing nerve). The auditory nerve sends sound information from the ear to the brain.
Hearing loss happens when any part of the ear is not working appropriately. Common types of hearing loss are:
- Unilateral hearing loss: Hearing loss in only one ear
- Bilateral hearing loss: Hearing loss in both ears
- Congenital hearing loss: Hearing loss that is present at birth
- Acquired hearing loss: Hearing loss that appears after birth, at any time in one’s life
- Conductive hearing loss: Conductive hearing loss is present when there is a problem with the outer ear or middle ear and slows or prevents sound waves from passing through. Causes of conductive hearing loss include: impacted ear wax, ear infections, foreign objects in the ear canal, holes in the eardrum, missing outer ear or ear canal, etc. Conductive hearing loss is often temporary and can usually be treated with medicine or surgery.
- Sensorineural hearing loss: Sensorineural hearing loss happens when the inner ear or auditory nerve is damaged or not working properly. Causes of sensorineural hearing loss include aging, genetics, noise exposure, certain medications, etc. This type of hearing loss is typically permanent and can likely be treated with amplification.
- Mixed hearing loss: Mixed hearing loss means the newborn has both conductive hearing loss and sensorineural hearing loss.
- Auditory neuropathy spectrum disorder (ANSD): ANSD is a hearing problem where the ear detects sound normally, but has a problem sending it to the brain. Someone with ANSD may experience difficulty differentiating sounds or struggle to understand speech clearly.
How do you know if your baby has hearing loss?
The Center for Disease Control (CDC) and the American Academy of Pediatrics (AAP) recommend that all babies are screened for hearing loss before 1 month of age. In most developed countries, newborn hearing screening programs have ensured most infants get their hearing checked as part of a newborn screening before they even leave the hospital or birthing center. If a baby fails a screening, it does not necessarily mean they have hearing loss, but a diagnostic hearing evaluation by a pediatric audiologist is recommended before three months of age.
Knowing risk factors for congenital hearing loss and appropriate developmental milestones can also help parents identify potential hearing difficulties in their children. If an infant is diagnosed with hearing loss, early intervention is incredibly important. Every state in the U.S. has an Early Hearing Detection and Intervention (EHDI) program in place. EHDI programs assist children with hearing loss and their families with obtaining diagnostic hearing evaluations and other services.
What hearing tests are part of newborn screening?
Newborn babies typically receive one of these hearing tests as part of a newborn screening:
Otoacoustic emissions (OAEs): Babies can sleep during an OAE test and are not required to respond. OAEs evaluate how the inner ear responds to sound by placing an earphone in the baby’s ear and playing sounds that echo in the ear canal. If an echo is not present or not detected, the baby may have hearing loss.
Auditory Brainstem Response (ABR): Babies can sleep during an ABR and are not required to respond. ABR requires patches called electrodes to be placed on the baby’s head and soft earphones in the ear. The audiologist sends sounds through the earphones and measures the infant’s brain waves on a computer to see how the brain responds to sound. This test can show if the brain is getting sound information in a clear way or not.
What other kinds of hearing tests can babies have?
If a newborn does not pass the ABR or OAE test in the hospital, the family will be referred to a pediatric audiologist. Audiologists are health care providers who specialize in the diagnosis and treatment of hearing and balance disorders in newborns, children, and adults. The family may also be referred to an otolaryngologist (ENT) physician, who specialized in ear, nose, and throat care.
At the audiologist’s office, newborns will receive a diagnostic hearing evaluation to identify hearing loss. This evaluation appointment may include ABR, OAE, and other hearing tests. For newborns, the audiologist may use Behavioral Observation Audiometry (BOA) to check how all three parts of the baby’s ear are functioning. During BOA, the audiologist plays a sound and watches how your baby responds by looking for specific changes in behavior. For example, the baby’s eyes may move or they may turn their head, suck on a pacifier, quiet down, or seem to be listening for another sound. If the baby responds, the audiologist gives them a reward, like a toy with engaging flashing lights. This is called visual reinforcement audiometry (VRA). Babies do need to be awake during this type of evaluation.
How can hearing loss affect your baby?
The importance of early identification and intervention of any condition, disease, or illness, is well-known. This sentiment holds true for hearing loss, especially in newborns and children. Early screening, diagnosis, and treatment can help children with hearing loss develop speech, language, and social skills at the same rate as their normal-hearing peers. However, without early treatment, hearing loss can lead to delayed speech and language development and learning and social problems.
Listed below are some developmental effects of untreated hearing loss in children:
- Speech and language delay: If a child cannot hear speech, they have difficulty learning how to reproduce speech sounds correctly. Babies and children with hearing loss may experience trouble understanding things others say, learning new words, and saying words correctly. The earlier a child with hearing loss receives treatment, the better chance they have at developing speech and language normally.
- Reading: If a child does not learn language due to an untreated hearing loss, they experience difficulty learning how to read, including grammar, spelling, and syntax. Delays in reading abilities are associated with late-identified hearing loss.
- Social: Social isolation can be common in children with untreated hearing loss. Not having the ability to interact with their peers because they cannot hear makes it difficult for children with hearing loss to integrate and be social.
- Cognitive: Lack of auditory signals to the brain can result in decreased cognitive ability over time. Recent research shows a link between dementia and untreated hearing loss in older adults; however, this cognitive decline can also be seen in children with untreated hearing loss.
- Behavioral: Children who have difficulty hearing and communicating their wants and needs act out more because they do not know any other way of expression.
How can you prevent hearing loss in your baby?
It can be difficult to identify a specific cause behind most hearing losses; however, about half of congenital hearing losses are genetic and cannot be prevented. If family history of hearing loss is present, genetic testing and genetic counseling can be helpful before becoming pregnant. A genetic counselor is a person who is trained to help families understand how genes, birth defects, and other medical conditions can affect their health and their babies’ health.
Genetic congenital hearing loss cannot be prevented at this time; however, expecting mothers can help prevent hearing loss related to other causes (ex: infections, prematurity).
Before pregnancy:
- It is recommended to get a preconception checkup to look for health conditions that may affect pregnancy and the health of the baby. Preconception checkups are encouraged, even if a person has already had a baby, as their health may have changed since the last pregnancy.
- Staying up-to-date on vaccinations can help protect expecting mothers from certain harmful infections. Some infections (measles, rubella) are associated with congenital hearing loss.
- Early testing and treatment for any sexually transmitted infections (STIs) can help mothers have a healthy pregnancy and healthy baby.
During pregnancy:
- Expecting parents are encouraged to attend all prenatal care checkups, even if they are feeling fine.
- Stay protected from infections while pregnant. Here are some recommendations:
- Stay up-to-date on vaccinations.
- Frequent hand washing, especially after using the bathroom or blowing your nose.
- Practice safe sex.
- Do not eat overcooked meat.
After birth:
- Babies should attend all well-baby checkups to examine overall health, growth, and development. At the well-baby visits, infants may get vaccinations to help protect them from harmful infections.
- If you think your baby has an ear infection, call their healthcare provider right away. Ear infections cause temporary hearing loss and can affect speech and language development if not treated. Signs of ear infection in children include:
- Tugging on ears
- Having trouble hearing or sleeping
- Crying more than usual, especially when the baby is lying down
- Fever
- Headache
- Fluid coming out of the ear
The importance of identifying children with hearing loss as early as possible has been emphasized for many years as undetected hearing loss can compromise optimal speech and language development and personal achievement. Without appropriate opportunities to learn language, children with hearing loss can fall behind their normal-hearing peers in language, cognition, social-emotional development, and academic achievement. However, research continues to show that when hearing loss is identified early and followed immediately with appropriate intervention, outcomes in several areas such as language development, communication competency, and social-emotional development will be significantly better.
Over the years, much time and effort has been devoted to finding the most efficient and accurate procedures, protocols, and equipment for screening, diagnosing, and treating children with hearing loss. Now, virtually all newborns in the United States are being screened for hearing loss before leaving the hospital. Certainly, the likelihood of an infant receiving timely and appropriate services is better than ever before.
