The newborn hearing screening (NHS) is a standardized, non-invasive procedure administered to nearly all babies in the United States and many other countries before they leave the hospital. This routine testing is a simple yet powerful measure designed for the early detection of hearing loss. Identifying hearing issues shortly after birth is paramount because it allows for intervention to begin as early as possible. Timely action is associated with significantly better outcomes for a child’s speech and language development.
The Standard Screening Process and Duration
The initial newborn hearing screening is designed to be a quick, efficient process, typically taking only 5 to 10 minutes. The screening uses specialized equipment to objectively measure how the baby’s auditory system responds to sound. This rapid test is usually performed while the baby is sleeping or resting quietly.
Two main methods are used for this initial check: Otoacoustic Emissions (OAE) and Automated Auditory Brainstem Response (AABR). The OAE test checks the function of the inner ear by measuring a tiny echo produced by the cochlea when sound is presented into the ear canal. The AABR test assesses the pathway of the auditory nerve and the brainstem’s response to sound, using small sensors placed on the baby’s head and neck to measure brainwave activity. Both procedures require the baby to be calm and still to ensure an accurate reading.
Understanding Screening Results
The result of the initial screening is reported as either a “Pass” or a “Refer.” A “Pass” result indicates that the baby’s hearing mechanism responded appropriately to the sounds presented during the test. This suggests that the baby’s hearing is likely within the typical range at the time of the screening.
A “Refer” result means the baby needs a re-screen, but it does not confirm a permanent hearing loss. Screening programs are intentionally sensitive to avoid missing potential cases, which means they sometimes generate a “false positive” result. Common, temporary reasons for a referral include the presence of amniotic fluid or vernix (a waxy coating) in the ear canal, or interference from excessive baby movement or environmental noise.
If the baby does not pass the first time, a re-screen is scheduled, often before the baby leaves the hospital or within the first few weeks of life. If the baby receives a “Refer” result on the re-screen, the next step is a comprehensive diagnostic evaluation with a pediatric audiologist. It is estimated that about 90% of newborns who initially receive a “Refer” result will go on to pass a subsequent screening.
Follow-Up Diagnostic Testing
Babies who do not pass the re-screening are scheduled for a definitive diagnostic test. This follow-up is typically a comprehensive Auditory Brainstem Response (ABR) test performed by a trained audiologist, often requiring 1 to 2 hours to complete the full assessment.
The audiologist uses advanced ABR equipment to measure the softest levels of sound the baby’s ear and auditory nerve can detect across different pitches. This involves careful preparation, including cleaning the skin and placing electrodes on the head and behind the ears. The baby must be in a deep, natural sleep for the entire testing period to prevent muscle movement from interfering with the precise measurements.
The goal of this diagnostic ABR is to determine the specific degree and type of hearing loss, if one is present, which is information needed to plan intervention. This entire process is guided by the “1-3-6” rule, a set of benchmarks recommending that screening be completed by 1 month of age, a diagnosis made by 3 months of age, and enrollment in early intervention services begin by 6 months of age. Meeting these targets helps ensure that a child with hearing loss receives the necessary support.