Two to three out of every 1,000 children are born with permanent childhood hearing loss. And finding out who they are can be tricky, since the patients haven't yet developed the ability to tell you what's wrong.
But given what's at stake, early detection is crucial. Most health systems test newborns within their first day or two, said Jill McClelland, manager of audiology at Penn State Health. McClelland holds a Doctor of Audiology and other degrees. In Pennsylvania, newborns' hearing is screened through the Pennsylvania Hearing Screening and Intervention program, and the program aims to test babies within their first 30 days.
The goal of the program is to diagnose the hearing loss within three months and enroll the child to receive treatment and intervention services by month six.
The importance of the world your child listens to stretches beyond enjoying music and soundscapes. Much of a human being's development – from how they speak to how they interact with the world – owe to the cute little satellite dishes attached to the sides of a baby's noggin. The first steps you take to understand your child's ability to hear can be just as important as any other decision you'll make in their lives.
Below, McClelland talks about hearing loss in children – what causes it, what to look for and how to make sure your newborn is covered.
What causes children to lose their hearing?
Sometimes, the hearing loss is genetic, and it can be hard to predict just by observing your family. Hearing loss is a recessive trait carried on the connexin 26 gene, McClelland said, so your family may not even realize it's there until along comes your first child with a difference.
Non-genetic illnesses in the mother can also cause hearing loss. A human ear canal generally forms in a fetus between week 20 and 25, so infections in that time span can be worrisome, McClelland said. In years past, rubella was a frequent culprit, but vaccines mostly tamped it down. These days, cytomegalovirus, or CMV, is often a problem. "We've seen an uptick," McClelland said. It often has no symptoms in an adult, but in a baby, CMV can destroy a child's ability to hear.
Other causes are more benign. Doctors sometimes discover amniotic fluid in a baby's ear canal, like they've had a dip in the pool and some of the water became stuck. Once it's removed, the hearing returns to normal.
But not every post-birth discovery is so kind. For example, a rare, genetic disorder called Usher Syndrome can cause hearing and vision loss over a period of years.
Some children lose their hearing the same way many adults lose theirs - through external, environmental factors. Loud noises, for example. A young hunter failing to adequately protect his or her ears might suffer hearing loss.
I personally have seen children where the cause has been video games and headphones."
Jill McClelland, manager of audiology at Penn State Health
How do you test a newborn's hearing?
The National Institutes of Health recommends two tests.
- Otoacoustic emissions tests involve inserting an earphone into the newborn's ear canal that plays sounds and tests for echo responses.
- Auditory brain stem response tests include affixing electrodes to your child's head and inserting earphones into the ears. A machine measures the brainstem's response.
Do you test every baby?
That's the idea. "The state does a very good job with it," McClelland said, and working through the Pennsylvania Hearing Screening and Intervention program, health care professionals manage to test about 95% of the births in the keystone state.
That includes the plain community in parts of rural Lancaster County, home to some of McClelland's patients. Midwives are often equipped with kits to perform the tests at the homes of families with new babies.
However, testing doesn't guarantee the other key ingredient of the screening program's success – follow up visits. If the screening suggests test shows hearing loss, the parents must make follow-up visits with an audiologist to determine why.
In the plain community, additional factors, such as transportation or cultural and religious beliefs, may make it hard to convince parents to follow up, McClelland said. That's particularly worrisome in a community where some studies have shown a possible genetic predilection for hearing loss.
What if testing doesn't catch it?
"Follow your gut," McClelland said. "A hearing screening is just a screening."
Watch for possibilities that your child might be struggling to hear. If you can sneak up on and startle a child easily, it might be because something is wrong.
Later, you might notice the hearing loss through your child's development. They may have trouble pronouncing certain words. Difficulty with grammar might owe itself to hearing problems. For example, if a child using a singular version of a verb or a plural version of a noun fails to recognize the S sound, it might be a hearing issue.
If you suspect a problem, take your child to see your pediatrician and ask for a screening.
What's the cure?
Usually, hearing lost is gone forever - but that doesn't mean there's no hope.
Medical science has made strides in its ability to supplement hearing. Children as young as nine months old can receive a cochlear implant, for example, which, using surgically implanted microphones, speech processors and transmitters can improve the understanding of language and help with a child's development.
As of December 2019, about 118,000 cochlear devices had been implanted in the U.S.
Sixty-five-thousand of the recipients were children.