Screening for hearing problems within the first weeks of life benefits children, especially when interventions quickly follow the detection of any impairments, suggests a new study of more than a half million Dutch children.

“Hearing is essential to the development of speech and language and it is believed that early treatment of hearing loss, as this study would seem to indicate, results in better speech and language outcomes,” Dr. Donald G. Keamy of the Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, who was not involved in the study, told Reuters Health in an email.

Between one and four of every 1,000 babies born in the U.S. will have a hearing impairment, making it the country’s most common birth defect.

Since the U.S. Preventive Services Task Force’s recommendation that all newborns be screened for hearing loss became widely adopted over the last decade or so, more of these cases are getting detected far earlier than the previous average age of 3 years.

Approximately 97 percent of newborns in the U.S. are now screened, according to the Centers for Disease Control and Prevention. And the National Center for Hearing Assessment and Management estimates that costs for the test have dropped to between $10 and $50 per baby.

The Netherlands, too, has embraced universal hearing screening among their newborns. And, like the U.S., its adoption was gradual.

Dr. Anna M. H. Korver, of Leiden University Medical Center, and her colleagues took advantage of the natural diversity of screening methods within their country during this transitional time to assess the new strategy’s costs and benefits.

They analyzed outcomes of nearly 600,000 Dutch babies born between 2003 and 2005, comparing children born in regions in which newborn hearing screening had already become the norm to those born where distraction hearing screening, a behavioral test conducted around the age of 9 months, continued to be the standard.

Among children undergoing newborn screening, fewer than one (0.78) of every 1,000 were diagnosed with hearing loss. Similarly, 0.73 of every 1,000 babies were diagnosed using the distraction hearing test, the researchers report in the Journal of the American Medical Association.

Compared to distraction screening (performed at around 9 months of age), the researchers found that newborn screening led to more spoken and fewer signed words, as well as better social and motor development at 3 to 5 years of age. These children also scored higher on measures of overall quality of life.

Two different types of hearing screening tests may be used to screen hearing in newborns. In one of the tests, called otoacoustic emissions, a miniature earphone and microphone are placed in the baby’s ear, sounds are played, and a response is measured. If a baby hears normally, an echo is reflected back into the ear canal and is picked up by the microphone. When the baby has a hearing problem, no echo is heard.

In the other test, called auditory brainstem response, sounds are played in the baby’s ears and band-aid-like electrodes are placed on the baby’s head to detect responses. This test measures how the hearing nerve responds to sounds and can identify babies with hearing loss.

Both tests are safe and comfortable.

When hearing loss is found, many treatments can be implemented such as hearing aids, inner ear implants and speech and language development programs.

“These treatments have benefits at all ages, but there is (far more to) gain in providing them early in life, as that is the time at which the infant brain is ‘primed’ for this kind of experience and learning,” Barbara Cone of the University of Arizona, in Tucson, who was not involved in the study, told Reuters Health in an email.

“In the 21st century, cognitive and communication abilities are at a premium. Our developed societies are dependent on high levels of literacy,” added Cone. “Understanding and producing spoken words is a key to literacy. Thus, providing programs, such as newborn hearing screening, that achieve higher developmental outcomes and quality of life, become important for the future well-being of society.”

Unfortunately, as the researchers note, not all detected hearing problems in the study were followed by early interventions.

Further, passing newborn hearing screening does not exclude babies from developing hearing loss later in childhood, added Keamy.

“This is not going to change what we’re doing in the U.S., because we’re already doing the screening,” Dr. Debara L. Tucci of Duke University Medical Center in Durham, North Carolina, who was also not involved in the study, told Reuters Health. “But it is a nice demonstration and confirmation that we’re doing the right thing.”

“Parents should take newborn hearing screening results seriously,” recommended Keamy. “If a child does not pass his newborn hearing screening, the child should be evaluated and tested by a specialist within the first few weeks of life.”

“Children who pass their newborn hearing screening should have their hearing screened again if there is notable delay in speech or diminished response to sound,” he added.

SOURCE:  Journal of the American Medical Association, October 20, 2010.