Infant hearing testing is a standard procedure to identify potential hearing loss in newborns shortly after birth. Early detection allows for timely interventions, which can influence a child’s speech, language, and cognitive growth. This process supports a child’s overall development by addressing hearing concerns proactively.
Routine Newborn Screening Tests
The initial assessment of an infant’s hearing involves two non-invasive methods: Otoacoustic Emissions (OAE) and Automated Auditory Brainstem Response (AABR), also known as ABR. These tests are performed within the first few days of life, often before the baby leaves the hospital.
Otoacoustic Emissions (OAE) testing measures sounds produced by the inner ear’s outer hair cells in response to a soft clicking sound. A small probe with a loudspeaker and microphone is placed gently inside the baby’s ear canal. If the outer hair cells function properly, they vibrate and produce a faint echo, or otoacoustic emission, which the microphone detects. The presence of these emissions indicates the inner ear is working as expected.
The Automated Auditory Brainstem Response (AABR) test assesses how the auditory nerve and brainstem respond to sound. This method involves placing small electrodes on the baby’s head, typically behind the ear and on the forehead. Soft clicking sounds are presented through small earphones over the baby’s ears. The electrodes record the brain’s electrical activity in response to these sounds, providing information about the pathway from the ear to the brainstem. This test can identify hearing loss affecting the auditory nerve or brainstem, which OAE might not detect.
Understanding Screening Results
Following the initial newborn hearing screening, results are categorized as either “pass” or “refer.” A “pass” result indicates the baby’s hearing response falls within the expected range for newborns. This suggests the baby has typical hearing at the time of the test, and no further immediate action is required.
A “refer” result means the baby did not pass the initial screening. A “refer” does not diagnose hearing loss; it signifies the need for further evaluation. Factors leading to a “refer” result include fluid in the ear canal, a restless baby during the test, or environmental noise. A “refer” result prompts a re-screening, often within a few weeks.
If the baby refers again after the re-screening, a comprehensive diagnostic audiological evaluation is recommended. This assessment is performed by a pediatric audiologist. Diagnostic tests, such as a diagnostic ABR, provide detailed information about the type, degree, and configuration of any hearing loss. This evaluation helps determine an accurate diagnosis and guides next steps for intervention.
When to Seek Further Evaluation
Even after a successful newborn hearing screening, parents should remain attentive to their child’s auditory development. Hearing abilities can change, and some forms of hearing loss can develop later in infancy or childhood. Observing age-appropriate auditory milestones helps identify concerns that may arise after the initial screening.
By three months of age, infants should startle to loud noises and recognize a parent’s voice. By six months, babies turn their eyes or head toward sounds and begin to babble. Between nine months and one year, a child should respond to their name, understand simple words, and begin to say their first words. A consistent lack of response to sounds or a delay in speech and language development warrants further investigation.
If parents notice any of these signs or have concerns about their child’s hearing or communication development, they should consult their pediatrician. The pediatrician can provide guidance, conduct an initial assessment, and refer the family to a pediatric audiologist for a specialized evaluation.