Hearing is fundamental for a baby’s overall development, shaping their ability to learn speech, language, and interact socially. Early detection of any hearing differences allows for timely support, which can significantly influence a child’s communication skills and learning.
Newborn Hearing Screening
Universal newborn hearing screening is a standard procedure designed to identify potential hearing loss soon after birth. These screenings typically occur before a baby leaves the hospital, often while the infant is sleeping. Two primary tests are used: the Otoacoustic Emissions (OAE) test and the Automated Auditory Brainstem Response (AABR) test. Both methods are safe and comfortable for newborns.
The OAE test involves placing a small probe, containing a miniature earphone and microphone, into the baby’s ear canal. Sounds are played, and if the ear functions normally, an “echo” or emission is reflected back and measured by the microphone. This test primarily assesses the function of the outer hair cells in the cochlea. A “pass” result indicates the ear responded as expected, while a “refer” suggests further evaluation.
The AABR test involves placing small, band-aid like electrodes on the baby’s head, typically on the forehead and behind each ear, and small earphones in the baby’s ears. Sounds are played, and the electrodes detect the brain’s electrical activity in response to these sounds, measuring the hearing nerve’s response. This test provides information about how the auditory nerve and brainstem are functioning. A “refer” result from either screening indicates that a more comprehensive diagnostic evaluation by an audiologist is recommended.
Key Developmental Hearing Milestones
Observing a baby’s responses to sound as they grow can also provide insights into their hearing development.
From birth to three months, a baby with typical hearing will often startle or cry in response to loud sounds and quiet down when soothed by soft sounds or a parent’s voice. They may also turn their head towards a speaker and smile in response to voices.
Between four and six months, babies typically begin to turn their head or look toward new sounds and respond to changes in the tone of voice. They might also start to imitate their own vocalizations, such as “ooh” and “aah” sounds, and show enjoyment from toys that make noise. They begin to pick out speech components, laying groundwork for language understanding.
From seven to twelve months, a baby usually responds to their own name and turns or looks up when called. They may start to babble with different sounds, imitate simple words, and respond to requests like “come here.” Babies in this age range also begin to recognize words for common items and enjoy interactive games like peek-a-boo.
Steps to Take If You Have Concerns
If concerns arise from a newborn hearing screening or if a baby does not meet expected hearing milestones, it is important to consult a pediatrician promptly. The pediatrician can then refer the family to a pediatric audiologist for comprehensive diagnostic testing. Early diagnosis of hearing loss, ideally before three months of age, allows for timely intervention, which can significantly improve speech and language outcomes.
An audiologist may perform several diagnostic tests to determine the presence, type, and degree of hearing loss. These can include a diagnostic Auditory Brainstem Response (ABR) evaluation, which is more detailed than the screening version and can estimate hearing thresholds. Another test is the Auditory Steady State Response (ASSR), which can also estimate hearing levels. Tympanometry is often used to assess the middle ear’s function and detect issues like fluid behind the eardrum, though it does not directly test hearing itself. If hearing loss is confirmed, early intervention services can then be initiated, providing support and strategies to help the child develop communication skills.