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LESSON 174

Risk indicators and monitoring

Year 2
Spring semester
Hearing Screening
Screening programs
Duration: 11:09

Does every baby who passes screening hear normally for life? In this lesson we cover the causes of late-onset and progressive loss, the JCIH 2019 risk indicators and assessment timelines, surveillance, and the family's observation checklist.

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Hello, and welcome to the AIHEAR Audiology Academy.
In this lesson we will learn the risk indicators for hearing loss and which babies need monitoring even after passing screening.
Using the 2019 recommendations of the Joint Committee on Infant Hearing, or JCIH, we will see who is assessed when, and how.
Newborn screening only shows the status on that day; hearing loss can begin months or years after birth.
This is called late-onset hearing loss.
In some children, a loss that was mild at birth gets worse over time; this is called progressive loss.
Screening tests may also miss very mild losses or losses in a narrow frequency region.
So a loss found later in a child who passed screening is not always a newly started loss.
Studies show that the prevalence of permanent childhood hearing loss rises clearly from the newborn period to school age.
To catch part of this rise, babies with risk indicators are monitored on a planned schedule.
One of the most important causes of late-onset and progressive loss is congenital cytomegalovirus, or CMV, infection.
Loss due to congenital CMV may be absent at birth, begin later, fluctuate and progress.
Some genetic losses are also progressive; enlarged vestibular aqueduct is one example.
In this condition the loss can worsen in steps, sometimes after a minor head injury.
Postnatal infections such as bacterial meningitis can also cause sudden and severe loss.
Some drugs, such as aminoglycoside antibiotics and cisplatin, can be ototoxic.
Head trauma affecting the temporal bone is also among the causes of hearing loss.
Middle ear fluid usually causes a temporary, not permanent, conductive loss; but if it lasts long, it can affect language development.
The JCIH 2019 position statement groups risk indicators by the timing of the first diagnostic evaluation.
A family history of permanent hearing loss beginning in childhood is the first indicator; age-related or noise-induced losses do not count.
A stay of more than five days in the neonatal intensive care unit is also a risk indicator.
Hyperbilirubinemia, or severe jaundice, requiring exchange transfusion is on this list regardless of length of stay.
Receiving aminoglycoside antibiotics for more than five days also calls for monitoring.
Severe lack of oxygen at birth, called asphyxia, or related brain injury is also among the indicators.
Prenatal infections such as herpes, rubella, syphilis and toxoplasmosis are also on the list.
Craniofacial anomalies and syndromes associated with hearing loss are also in this group.
For a baby with any of these indicators, a diagnostic audiological evaluation is recommended by 9 months at the latest, even after a pass.
For some indicators, the risk of progression is high, so evaluation is done earlier.
For babies diagnosed with congenital CMV, a diagnostic evaluation is recommended by 3 months at the latest.
Babies who received ECMO, a life support machine that temporarily takes over heart and lung function, are also in this group.
Children with culture-positive meningitis or encephalitis are evaluated within 3 months of the event at the latest.
Because the cochlea can ossify after meningitis, this evaluation sometimes becomes much more urgent.
After significant head trauma or chemotherapy, evaluation is also done within 3 months of the event at the latest.
Concern from the family or caregiver about hearing, speech or language development calls for immediate evaluation.
Among the risk indicators, congenital CMV is one where timing is most critical.
To show that the infection is congenital, the sample usually has to be taken within the first three weeks of life.
This test is usually done by looking for the virus in a saliva or urine sample.
After this period, a positive result cannot tell whether the infection was acquired before or after birth.
So some programs give targeted CMV testing to babies who do not pass screening, while others screen all newborns.
A baby found to have congenital CMV is placed on an audiological monitoring schedule, even after passing screening.
The testing decision and interpretation of results are the physician's responsibility; the audiologist builds this into the monitoring plan.
Most babies with a risk indicator hear normally; the indicator only says the probability is higher.
So a risk indicator is explained to the family as the reason for monitoring, not as a definite problem.
On the other hand, about half of babies with congenital loss have no known risk factor; monitoring does not replace universal screening.
After the first evaluation, the frequency of monitoring is planned according to the indicator and the likelihood of progression.
For example, in congenital CMV, monitoring continues at regular intervals up to school age.
Some indicators, such as meningitis or trauma, appear after birth, so the risk assessment is renewed at every visit.
Compared with the 2007 statement, JCIH 2019 tailored monitoring to each indicator and aimed to reduce unnecessary repeat testing.
The diagnostic evaluation of a nine-month-old usually combines behavioral and objective tests.
At this age, visual reinforcement audiometry, or VRA, can usually be done.
When the baby hears a sound, they turn their head toward the loudspeaker and are rewarded with a lighted toy.
VRA with insert earphones gives separate, frequency-specific thresholds for each ear.
Tympanometry and otoacoustic emissions give complementary information about the middle ear and cochlea.
In babies older than six months, a 226 hertz probe tone can now also be used for tympanometry.
If behavioral testing is not reliable or the findings disagree, frequency-specific auditory brainstem response testing is done.
Monitoring is not only audiology appointments; in primary care, every well-child visit is an opportunity for surveillance.
At these visits, the child's auditory behavior, language milestones and middle ear status are reviewed.
The goal of surveillance is to notice early a child whose development drifts from the expected path, with or without a risk indicator.
When the family or physician raises a concern, the child is referred for audiological evaluation without delay.
For children with risk indicators, audiological evaluations follow a schedule planned according to the indicator.
Middle ear fluid is a common and treatable problem, but it can hide a permanent loss or add to one.
Recording all results and sharing them with the family physician keeps monitoring from breaking down.
Tell families to watch whether the baby reacts to sudden, loud sounds.
As the baby grows, they are expected to turn toward the sound when their name is called.
A decrease in vocal play such as cooing and babbling is also a sign to watch for.
Most children say their first meaningful words around one year of age; a clear delay should be evaluated.
A clearly small vocabulary and not combining words around age two are also warning signs.
A decrease in words or responses the child already had is always evaluated without waiting.
The family is told clearly that they can come in without waiting for the next planned appointment when they are concerned.
A tip from the field: the risk indicator field in screening records is often left incomplete or filled in vaguely.
Ask one by one how many days were spent in intensive care, which drugs were used and for how long, and how jaundice was treated.
In the family history, try to tell whether the loss began in childhood and whether it is permanent.
If a congenital CMV test was done, record the result; if not, note that too.
Missing risk information can leave a child who needs monitoring outside the monitoring system.
In this lesson we saw that passing screening does not mean hearing will stay normal for life.
Under JCIH 2019, most risk indicators call for a diagnostic evaluation by 9 months, even after a pass.
Congenital CMV and ECMO call for evaluation by 3 months; meningitis, trauma and chemotherapy within 3 months of the event.
The family's concern is always taken seriously and calls for immediate evaluation.
Test yourself: a baby with congenital CMV passed screening. By when should the first diagnostic evaluation be done?
The correct answer is A: by three months of age at the latest.
Because loss from congenital CMV can begin later and progress, these babies are monitored earlier and regularly.
In the next lesson we will look at the diagnostic process for a baby who did not pass screening and how to reduce loss to follow-up.
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