Babies born in the United States just have to accept that they’re in for some poking and prodding. There is a small litany of procedures they have to endure to make sure all systems are a go. One of them is a newborn hearing screening. Over 95 percent of U.S. babies will have a hearing test by the time they are one month old — usually at the hospital before discharge.

The purpose is to determine if the child is one of the approximately 0.3 percent of people born with hearing loss. As is the case at any age, the earlier hearing loss is detected the sooner countermeasures can be taken. This is especially critical with regards to babies developing language skills, since this begins prior to age six months and is most intense over the first three years of life.

Two primary tests are used. Babies oftentimes sleep through them.

An earphone is placed in each ear for the otoacoustic emissions (OAE) test. Sound is played into the ear and the corresponding echo — the reflection of the sound — is measured. There’s a distinct pattern if the baby’s ears are operating within normal parameters.

With the auditory brain stem response (ABR) test, along with earphones, there are electrodes placed on the head that measure the activity of the auditory nerve and brain stem to sound stimulus. This ensures that those vital parts of the human hearing system are working normally.

These tests are nonintrusive and, as noted, babies often sleep right through them.

They are highly accurate, though false positives are not uncommon. If there’s any sign of hearing issues, parents will be directed to consult with a hearing professional for further testing before age three months.