RALEIGH, N.C. — If there are problems with speech and social development for newborns, hearing loss could be at the root of it.

Medical experts say that testing for hearing problems early in a baby's life is very important.

So, many hospitals work to catch the problem as early as possible.

New mom Cortina Harris is more than happy to have nurses at Rex Hospital test her baby girl, Sydney, for problems.

"You know, you worry from the time that you're pregnant until you actually see her --and they tell you that she's O.K.," said Harris.

A test measured Sydney's response to sound. She passed with flying colors.

But not every child does.

"Two babies per 1,000 will have a hearing loss," said Laurie Cain, a registered nurse at Rex Hospital. "And it actually is the most common congenital birth problem."

Tyler Hartman was one of those 2 out of a 1,000.

Then Brad and Jennifer Hartman learned Tyler's hearing loss was only mild to moderate.

Hearing aids on both ears help him hear everything.

More importantly, he hears his mom and dad's voice and he's developing normally.

But without the screening, diagnosis and help he might have had problems.

"He probably would have gone through his first three or four years of life losing a lot of the things he needed to be successful in life," said Brad Hartman.

Even children who pass the infant screening could still develop hearing problems later on.

So Harris and her doctors will look for any signs of problems with Sydney.

It's a challenge for nurses to perform all the recommended infant tests before mother and child go home.

Trained volunteers at Rex Hospital do half of all infant hearing tests.