Hearing screening is a tool used to identify hearing impairment, or hearing loss, in newborn babies and young children. A test that shows hearing impairment or unclear results is usually followed up with a detailed diagnostic assessment carried out by an audiologist.
Every baby is offered screening for hearing loss in the US. The sooner hearing loss is diagnosed, the better the outcomes. Hearing screening plays an important role in identifying and addressing hearing impairment because it can be difficult to tell if a baby has hearing loss during their first two months of life.
Hearing screening is non-invasive and is typically carried out by a nurse who has undergone specific training. Hearing screening can either be a single test, or a two-stage process. In two-stage screening, babies that show signs of hearing impairment in the initial test receive a second screening test. Only those showing a similar result in the second test are referred to an audiologist.
Hearing loss is classified by measuring the hearing threshold in decibels at various frequencies. Normal hearing has a threshold of 20 decibels (dB).
Hearing loss can be:
Babies and young children identified as having moderate to profound hearing loss can receive support and early intervention to minimize the impact of their hearing impairment.
A program of services designed to help babies and young children who have, or are at risk of having, developmental delays or disabilities.
A hearing specialist that can measure, diagnose and assess hearing problems.
There are typically two tests that may be used to screen for hearing loss in newborns; an automated auditory brainstem response test, and otoacoustic emissions test. Screening typically takes place before the baby is discharged from hospital. The baby needs to be asleep or in a quiet and settled state during the screening test.
This test measures the integrity of the inner ear and the auditory pathway. It can detect auditory neuropathy in children who are deaf, but who have normal otoacoustic emissions (as their cochlea is normal).
The stimulus is presented with either earphones or through an ear canal probe. Three specially-placed electrodes are used to detect the response from the brain stem. This is an automated device, so it can be performed by non-specialists. The test takes around 20 minutes to complete.
If the screening is not passed in one or both ears, the baby will undergo a second test, and may be referred to an audiologist for further assessment.
In a healthy cochlea, the hair cells vibrate in response to sound; this vibration generates acoustic energy, known as otoacoustic emissions.
This test measures the presence or absence of sound waves being generated by the hair cells on the cochlea in response to sound stimuli. A miniature microphone is placed in the outer ear canal and the microphone produces sounds stimuli and then detects sound waves generated by the cochlea.
If the screening test is not passed in one or both ears, the baby will undergo a second screening and may be referred to an audiologist for further assessment.
The area at the base of the brain that controls many of the body's most fundamental motor, sensory and reflex functions, as well as the facial muscles.
The spiral-shaped cavity of the inner ear, responsible for converting sound waves into nerve impulses that the brain recognizes as sound.
Any disease or condition that affects nerves or the nervous system.
A hearing specialist that can measure, diagnose and assess hearing problems.
Hearing is a critical part of a baby's cognitive, social and emotional development - a mild or partial hearing loss can affect their ability to speak and understand language. Young children with untreated hearing loss can experience delays in their language development, behavioral difficulties and underachieve at school.
It is estimated that around one in every 1000 babies is born with permanent hearing loss in both ears. The vast majority of deaf babies are born into families with normal hearing. [1]
For around half of all babies and young children with hearing loss, there is no associated cause.
Some possible causes of hearing loss in newborn babies may include:
Some other factors that can cause 'acquired hearing loss' any time after birth include:
Most babies who are diagnosed with some degree of hearing loss do not have any known risk factors, nor any underlying medical condition that is associated with hearing loss.
Babies with an increased risk of hearing loss include those with:
Babies at risk are typically offered repeat screening when they reach 9-12 months of age.
Newborn hearing loss can be:
Most newborn hearing loss is caused by sensorineural hearing loss. With up to half of cases due to genetic causes, the rest are acquired. It involves the cochlea or the auditory nerve.
Auditory neuropathy, one type of sensorineural hearing loss, is caused by absent or severely distorted auditory signals.
Conductive hearing loss is usually caused by abnormalities of the outer or middle ear, which limit the amount of external sound that can pass through to the inner ear. The function of the cochlea remains normal, because the inner, middle and outer ear develop separately.
Although hearing screening tests can identify the majority of babies with mild or more severe hearing loss, it is still important to monitor a young child's speech and language developmental milestones to detect late onset or progressive types of hearing loss.
During the first year, babies learn how to hear and recognize the sounds of their parents' language. They may experiment with sounds by babbling, which progresses to them making real words.
Some of the more typical milestones a baby reaches in their first year of life include:
Babies and young children experience huge development in their speech sounds. By the age of two, around half of their speech can be understood, and by the age of three, most of their speech can be understood.
As the baby grows, some signs that may be associated with hearing impairment may include:
Early intervention services for newborn babies identified with a hearing impairment will enable improved speech, language and academic performance.
Hearing loss can:
Adults with hearing loss can experience higher rates of unemployment.
Early intervention enables babies and young children to develop better language, speech and learning skills as their brain is exposed to language earlier. It is crucial for maximizing the potential speech and language development of babies with hearing loss.
Ways to help prevent hearing loss in babies and young children include:
Before the birth of a baby.
Chemical substances that kill or suppress the growth of bacteria.
An emergency lifesaving procedure that involves manually pumping air into the lungs, and compressing the chest to circulate the blood. This first aid technique is used when someone's breathing or heartbeat has stopped.
A highly contagious disease caused by infection with the varicella zoster virus. Its main symptom is a blistering skin rash.
The spiral-shaped cavity of the inner ear, responsible for converting sound waves into nerve impulses that the brain recognizes as sound.
Present from birth.
A common herpes-type virus that usually only causes a mild flu-like illness in healthy people, but that can cause a range of illnesses in people with compromised immune systems or babies of women who are infected while pregnant.
A program of services designed to help babies and young children who have, or are at risk of having, developmental delays or disabilities.
Inflammation of the brain, usually caused by a viral infection.
The extensive network of cells and structures that is responsible for activating and coordinating the body's functions, sensory input and cognition.
The period of time during which an embryo or fetus develops in the uterus. Usually, this occurs for 38 weeks after conception, which is about 40 weeks from the start of the last normal menstrual period in women with a four-week menstrual cycle.
The practice of administering a vaccine, a solution containing a microorganism (that causes a specific disease) in a dead or weakened state, or parts of it, for the purpose of inducing immunity in a person to that microorganism.
Any disease or condition that affects nerves or the nervous system.
Hearing loss that is caused by damage to the inner ear or the nerve connecting the inner ear to the brain (the auditory nerve).
Relating to cognition, which are the mental processes and abilities associated with acts of judgement, reasoning and understanding.
Newborn hearing screening. Australian Prescriber – an independent review. Accessed 6 November 6 2014, from