Judith Berger | Dec 28, 2011, 11:44 a.m.
Imagine never hearing “I love you,” the sound of your own name or the stillness of a snowfall. Everyday, life is made up of millions of sounds we take for granted. Much of the human experience is based on communication -- to understand and to be understood. For more than 30 million adults in the United States, substantial hearing loss is a reality; and nearly three out of every 1,000 babies are born deaf or hard-of-hearing.
The reality of this, and what could be, drives Dr. Christina Runge, PhD., CCC-A, an associate professor, chief of communication sciences and director of the Koss Cochlear Implant Program in the Department of Otolaryngology and Communication Sciences at the Medical College of Wisconsin. Her research focuses on cochlear implants and auditory neuropathy spectrum disorder.
Doctors at the Medical College of Wisconsin perform approximately 100 cochlear implant surgeries a year. More than 41,000 adults and 25,000 children have received implants in the United States.
Auditory neuropathy spectrum disorder is a hearing condition in children. “With ANSD, a child may hear beeps, but not speech,” she said. “Many times parents think it’s an attention problem, but it isn’t. It’s like dyslexia of the ear. The sound goes in, but gets mixed up. It’s a problem with the cells and nerves of the ear.”
The inner ear is made up of a snail-shaped chamber called the cochlea, which is filled with fluid and lined with rows of tiny hair cells. When the vibrations move through this fluid, the outer hair cells contract back and forth and amplify the sound. When the vibrations are loud enough, the inner hair cells translate them into electrical nerve impulses in the auditory nerve, which connects the inner ear to the brain. When the nerve impulses reach the brain, they are interpreted as sound.
Dr. Runge describes the effects of ANSD as hearing bursts of static. It can be diagnosed, however, practitioners can’t determine the severity of the disorder. Dr. Runge is working on the problem of defining the level of impairment and developing tests to diagnose ANSD at an earlier stage. “Defining the severity of impairment early gives the patient a better outcome.”
Diagnosing and defining impairment in infants is key to prevent delay or impairment of speech development. Wisconsin has a newborn screening program in place, Dr. Runge said, however, hearing loss can happen after birth.
Practitioners, clinicians and researchers listen to parents who suspect their child may have a hearing issue. “Parents usually see their child’s pediatrician first because they know something is not right with their baby’s hearing. Maybe the baby won’t startle or respond to sounds,” she said. Parents are then referred to a pediatric otolaryngologist.
Cochlear Implants:Controversy or Cure
According to the National Institute on Deafness and Other Communication Disorders, a cochlear implant is a small, complex electronic device that can help to provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing. The implant consists of an external portion that sits behind the ear and a second portion that is surgically placed under the skin. An implant does not restore normal hearing. Instead, it can give a deaf person a useful representation of sounds in the environment and help him or her to understand speech.
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