Cochlear implants have been available since the 1980s to restore hearing to people with profound hearing loss. Since then, most recipients have implants in only one ear. However, around 10 years ago, research began to confirm the benefits of bilateral cochlear implantation.
Studies have shown that there is a vast improvement in sound localization ability in patients with bilateral cochlear implants, says David Parry, MD, a fellowship-trained pediatric otolaryngologist (ears, nose and throat specialist) who performed the simultaneous bilateral cochlear implant procedure at University Medical Center in March. In particular, patients who were initially implanted bilaterally at a very early age improved the most.
Hearing is a two-side phenomenon, explains Dr. Parry. When a cochlear implant is placed in only one ear (unilateral implant), a patient does not receive complete auditory stimulation which can be critical to developing oral communication skills.
"For example, hearing becomes difficult in a noisy situation for a deaf person who has a cochlear implant only on one side," he says. "Bilateral cochlear implants can provide an almost normal ability to perceive and discriminate sounds.
"Nature has given us a pair of ears for good reason: having two ears improves our ability to locate sounds and understand one another in diverse situations," Dr. Parry says.
Bilateral implantation is especially important and useful in children who are deaf before they have learned to speak. They learn linguistic and communication skills faster and can grow into normal productive adults, he said. There are approximately 4,000 bilateral cochlear implant recipients in the world today. More than half are children.
The procedure involves surgically implanting an electronic device that directly stimulates the cochlear nerve of deaf individuals. An electrode carries signals from a small transmitter imbedded in the temporal bone right behind the ear into the coil of the cochlea, the shell-shaped structure in the inner ear that normally translates sound vibrations into electrical signals the brain can "hear."
A cochlear implant can restore useful hearing and provide improved communication abilities for adults and children who have bilateral (both ears) severe to profound sensorineural hearing loss. People who receive little to no benefit from hearing aids are considered for cochlear implant.
In Antony's case, there was not much time for his dad to decide to do the procedure. In response to the inflammation caused by meningitis, bone begins to grow in the inner ear and can make cochlear implantation impossible, so the procedure needs to be performed as soon as the child is well enough.
Hearing loss is the most common long-term after effect of meningitis, affecting up to one quarter of survivors, and meningitis is the biggest cause of acquired deafness in children.
EDITORS PLEASE NOTE: Interviews with the patient, Antony, his father, and Dr. Parry can be arranged by calling Jo Marie Gellerman, 520-626-7219. Also, b-roll of the procedure is available.
