Girl may get to hear for the first time
At age 3, Angelica Lopez is helping to break a sound barrier for deaf children.
She was born without working auditory nerves. But now she can detect sounds for the first time, and start to mimic them. The progress came after Angelica underwent brain surgery. A device was implanted that bypasses missing wiring in her inner ears.
Angelica is one of a small number of U.S. children who are testing what's called an auditory brainstem implant, or ABI. The device goes beyond cochlear implants. Those have brought hearing to many deaf children but don't work for tots who lack their hearing nerve.
When the ABI is first turned on, "she isn't going to be hearing like a 3-year-old. She'll be hearing like a newborn," said audiologist Laurie Eisenberg. She works at the University of Southern California.
The children don't magically understand and use those sounds.
"It's going to take a lot of work," Eisenberg cautioned.
Angelica cried when her ABI first was switched on. She was scared by the sounds. But five months later, her mother says the youngster uses sign language to identify some sounds. And she's beginning to babble like hearing babies do. Therapists are working to teach her oral speech.
"It's just so awesome to hear her little voice," said Julie Lopez of Big Spring, Texas, who enrolled her daughter in the study at USC, where researchers say she's progressing well.
Many children born deaf benefit from cochlear implants. They are electrodes that send impulses to the auditory nerve, where they're relayed to the brain and recognized as sound. But the small fraction born without a working hearing nerve can't make that brain connection.
The ABI attempts to fill that gap. It delivers electrical stimulation directly to the neurons on the brainstem, which the nerve normally would have targeted.
The person wears a microphone on the ear to detect sound. A processer changes it to electrical signals. Those are beamed to a stimulator under the skin, which sends the signals snaking through a wire to electrodes surgically placed on the brainstem.
The Food and Drug Administration approved the device in 2000. It was specifically for adults and teenagers whose hearing nerves had been destroyed by surgery for a rare type of tumor. It doesn't restore normal hearing, but can help to varying degrees.
Then about a decade ago, an Italian surgeon started trying the ABI in deaf children. Their young brains are more flexible. They might better adapt to this artificial way of delivering sound.
The first U.S. studies in young children are underway at a handful of hospitals. Hearing specialists are watching the work closely.
There are children "who are not being helped in any other way," said Dr. Gordon Hughes of the National Institutes of Health. It is funding Eisenberg's study. Cochlear implants proved there's a critical time window when the brain is very receptive to auditory stimulation, Hughes said. He said that time is with the youngest children.
The studies are small. Each enrolls 10 to 20 children. The Los Angeles study will implant starting at age 2, while some others try earlier. Children then receive intensive therapy, to learn to hear.
The studies must prove safety, since the ABI requires delicate brain surgery in healthy children.
"We're talking about real surgery to go into a deep area of the brain," said Dr. Marc Schwartz. He is a neurosurgeon with the House Clinic and Huntington Medical Research Institutes in Los Angeles. Schwartz is part of the USC study.
"This is a precise operation that requires exacting technique."
Critical thinking challenge: Why hasn't this technology been deployed with all deaf children?