Early hearing screening improves child development

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.