Newborn Infant Hearing Screening (cont.)
How common is hearing loss in infants?
Most permanent hearing loss is due to damage/malfunction of the nerve that transmits sound from the inner ear to the brain (auditory nerve). For those infants in whom a cause is determined, approximately
half have a genetic condition and the remaining half have an acquired condition to explain their hearing loss.
What are some of the causes of hearing loss in the newborn?
Hearing loss in a newborn can be caused by a number of conditions. Some of
the known risk factors include high bilirubin levels (jaundice), drugs that are
toxic to the ears (for example, medicines that are given to the newborn to
battle a serious infection may damage hearing as a side effect), prolonged
mechanical ventilation, low Apgar scores, meningitis, prematurity, and/or low
birth weight. Malformed structures in the middle or outer ear can also lead to
hearing loss. Viral illness during the pregnancy, such as rubella (German
measles) or cytomegalovirus (CMV), can be passed to the newborn and result in
hearing loss. Hearing loss can sometimes be inherited in abnormal genes passed
from the parents to the newborn or be the result of a gene mutation that
occurred during fetal development. Genetic counseling is often recommended for
parents to determine if heredity is the cause of the hearing loss. In
approximately half of all cases of hearing loss, the cause is never determined.
How is hearing in infants tested?
Hearing in infants can be tested using two different methods: the auditory
brainstem response (ABR) evaluations or the otoacoustic emission (OAE)
measures. Both tests are accurate, noninvasive, automated, and do not require any
observable response from the infant. Which test is used depends on the screening
program's choice of instrumentation and training. For a screening tool, both
methods are extremely effective. There are, however, some distinct differences
in how the hearing is measured using an ABR versus an OAE.
Next: What is an ABR test? »
- Detecting Hearing Loss in Children - Read about tests used for identifying hearing loss in children, treatment information, causes, risk factors and signs of hearing impairment, and learn about degrees of hearing loss.
- Pregnancy Planning - The goals of pregnancy planning are to create a healthy environment for the fetus and to prevent birth defects and other pregnancy related problems.
- Deafness, Hearing Loss - Hearing loss (deafness) may be present at birth or it may manifest later in life. Deafness may be genetic or due to damage from noise. Treatment of deafness depends upon its cause.
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