The Most Common Birth Defect
Beth Trama, of Smithtown, New York, was watching her son, Luca, sleep peacefully in the hospital nursery, when the newborn next to him let out a loud, high-pitched scream. Luca didn't wake up. Trama couldn't believe that the noise didn't startle him, but she assumed he'd just gotten used to being with all those crying babies -- until he failed his hearing screening the next day.
You're probably surprised to find out that hearing loss is the most common birth defect. Every day, about 33 babies are born in the U.S. with a hearing impairment. But the news hasn't gotten through to parents -- in fact, only 1 percent of new and expectant moms ranked hearing loss as their top concern about their child's health, according to a survey by the Alexander Graham Bell Association for the Deaf and Hard of Hearing, in Washington, D.C.
A Recessive Gene
Many parents figure their baby isn't at risk if they don't have a history of deafness in their family. However, about 90 percent of deaf children are born to hearing parents. Deafness can be caused by a dominant gene -- meaning one or both parents are deaf -- or by a recessive gene, so a child can inherit the trait even if no family members are hearing-impaired. That's what happened to Luca. After his diagnosis, doctors discovered that both of his parents had a recessive gene for a genetic disorder that damages the hair cells in the inner ear so they can't carry sound to the auditory nerve. As a result, Luca is severely deaf in both ears.
Hearing loss can also be caused by many nonhereditary factors, including infections, prematurity, severe jaundice, or a lack of oxygen during delivery, says Ellen M. Friedman, MD, chief of pediatric otolaryngology at Texas Children's Hospital, in Houston. Unfortunately, most of these causes aren't preventable.
Testing 1, 2, 3
You can't count on your baby's doctor to identify a problem -- most pediatricians don't have the proper equipment to do infant hearing tests in their offices.
Before you give birth, check with your hospital to make sure that hearing testing is part of their newborn screening process. If it's not, or if you give birth somewhere other than a hospital, ask your pediatrician to recommend a pediatric audiologist or otologist to screen your baby within her first three weeks. Hearing tests for newborns are mandatory in 42 states and in Washington, D.C. (although small hospitals may be exempt). "However, every baby's hearing should be tested at birth so that parents can get help quickly if there's a problem," says Simon C. Parisier, MD, cofounder of the Children's Hearing Institute, in New York City. Testing is especially crucial because research has shown that parents' impressions about their infant's hearing are often wrong. Even deaf babies can coo and make gurgling sounds. If you're not sure whether your baby has been tested, contact your hospital to check her records.
How It Works
A hearing test is easy and painless. Doctors use one of two measures: an otoacoustic emissions (OAE) test, which measures the response by the hair cells inside the ear when they're stimulated by sound, or an auditory brain-stem response (ABR) test, which measures brain-wave activity in response to sound. Both of these tests are given while the baby is asleep, and for babies, they're both pass-or-fail: They only tell doctors if a baby can hear 30 decibels (the sound of a whisper), which is the definition of normal hearing. If your baby fails the initial screening test, you need to make an appointment with an audiologist for more comprehensive testing in order to confirm the results, determine the severity of the loss, and get proper treatment.
"I wish I'd pushed the doctors to treat my baby's hearing loss sooner," says Heather Conar, of Nashville. Her son, Jacob, failed his hearing screening at birth, but he wasn't officially diagnosed with hearing loss and fitted for a hearing aid until he was more than a year old. "They thought the trouble was caused by fluid in his ears that would drain, but it turns out his hearing loss was permanent from the beginning," she says.
Doctors initially thought that Jacob had conductive hearing loss, which is caused by a blockage in the middle ear that makes sounds muffled. Babies who've had frequent ear infections can experience this type of mild, temporary loss due to fluid buildup in the ear. It can usually be corrected by putting tubes in the ears to drain the liquid. Sensorineural hearing loss, the kind that Jacob actually has, is more serious -- and usually permanent -- because it's caused by a problem with a child's auditory nerve. A child will need a hearing aid, which Jacob now has, or a cochlear implant (an electronic device that is surgically implanted behind the ear to stimulate the auditory nerve) in order to hear normally.
Even if your baby passes her infant screening test, it's important to continually pay attention to her behavior and reactions to sound, says Dr. Friedman. Hearing loss can be progressive or can occur as your child gets older. Risk factors for delayed-onset hearing loss include a family history of childhood hearing loss, recurring or persistent ear infections for at least three months, head trauma, and serious infections like bacterial meningitis. If you're ever concerned, take your child to get a hearing test.
Sadly, many kids aren't diagnosed with hearing loss until age 2 -- which is way beyond the critical window for developing speech and language skills. Your child learns to speak correctly by hearing sounds around him and listening to your voice. If he can't hear during his first six months, he's missing an important opportunity. Children with a hearing impairment often learn new words more slowly than other children, understand and produce shorter sentences, have trouble with quiet speech sounds like the "s," "sh," "f," "t," and "k," and don't do as well academically.
While it's never too late to get help, experts say that it's ideal to start early intervention -- including speech and listening training -- before 6 months of age. With an early diagnosis and hearing aids or other interventions, most kids who are deaf or hard-of-hearing will develop language skills comparable with their peers by first grade. Children as young as 3 months can be fitted with hearing aids, and those with profound hearing loss can get a cochlear implant at age 1. Cochlear implants have been controversial within the deaf community because they try to "fix" the trait that's central to deaf culture. "Having known many deaf people, I used to be more wary of implants, but now I've seen how fantastic they can be for kids," says Dr. Friedman. Children who have hearing aids or cochlear implants usually go to mainstream schools, can speak relatively clearly, and are less isolated than those who rely only on sign language.
To make the best decision for your child, it's important to speak to doctors, audiologists, and other parents. "We have a whole 'new family' of people who've helped keep us informed, find schools, interview surgeons, and do anything necessary to help our son," says Beth Trama. Luca got a cochlear implant just a few months before his first birthday. Now 3 1/2, he's communicating well, attending nursery school, and, most important, says Trama, "He's a happy, spunky little kid."
Can You Hear Me Now?
Even babies who pass the newborn hearing screening can develop hearing loss later on. If your baby doesn't reach these milestones, it's a good idea to have her hearing retested.
At 3 months
- Turns her eyes or head toward loud sounds
- Begins to imitate some sounds
- Smiles at the sound of your voice
At 7 months
- Looks at you when you call her name
- Responds to sound by making sounds
- Babbles chains of sounds like "ba-ba-ba-ba"
At 12 months
- Responds to "no" and simple requests
- Says words like "dada" and "mama"
- Understands common phrases like "bye-bye"
At 24 months
- Says at least 15 words
- Uses two- to four-word phrases
- Repeats words overheard in conversation
Source: Centers for Disease Control and Prevention; Alexander Graham Bell Association for the Deaf and Hard of Hearing