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| Oticon Medical bone-anchored implant |
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| Advanced Bionics cochlear implant |
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| Otodynamics hearing screener |
Every year, roughly two to three babies out of every thousand healthy newborns are diagnosed with hearing loss, and another two to three per thousand children are diagnosed with hearing loss before kindergarten. The incidence of hearing loss for infants in the neonatal intensive care unit (NICU) is almost 10 times as high. This is in part because premature babies are born before the organs are fully developed, including those involved with hearing, and they are more prone to complications overall. In addition, some NICU babies are given gentamicin or other ototoxic medications, which can result in a higher incidence of hearing loss.
Early identification of hearing loss is vitally important. Congenital hearing loss not only interferes with communication development and language acquisition, it can also result in across-the-board developmental problems. A baby's emotional and social progress can be affected.
"Early hearing detection has dramatically improved the landscape for infants and children who are deaf and hard of hearing," says Kathleen Treni, president of the Alexander Graham Bell Association for the Deaf and Hard of Hearing. "Immediate follow-up is absolutely essential. With the right technology and qualified professionals in partnership with families, the sky is the limit for these babies."
The Joint Committee on Infant Hearing, an organization comprised of audiologists, otolaryngologists, pediatricians, and nurses, first recommended universal newborn
screening in 1994. Now, thanks to strong advocacy in the late 1990s by Deafness Research Foundation and other groups, as well as advances in technology used to identify and diagnose hearing loss in infants, 97 percent of infants born in the United States receive hearing screenings at birth.
A technician or nurse can easily screen a newborn's hearing using automated equipment with fixed settings. Two types of technology power these screeners: automated auditory brainstem response and otoacoustic emissions. The first uses electrodes to record brain activity that occurs in response to sound. It provides valuable information about the sensory and neural auditory system, making it recommended for use in the neonatal intensive care unit. It can even be performed on a newborn when the child is sleeping or sedated.
The second type of technology relies on the fact that sound causes hair cells located in the cochlea, or inner ear, to vibrate. This stimulates the auditory nerve and produces very faint noise called otoacoustic emissions. (The cochlea, then, doesn't just receive sound, it also produces it.) By measuring otoacoustic emissions with extremely sensitive microphones, it is possible to determine how well the hair cells are working. Unlike automated auditory brainstem response screeners, however, otoacoustic emissions screeners test only a portion of the hearing systemfrom the outer ear to the cochlea.
By 6 months of age, the infant is developmentally able to participate in a behavioral hearing test and can undergo additional testing. Behavioral testing includes a technique called visual reinforcement audiometry. For this test, the baby is trained to respond to sound, such as by turning the head, with positive visual reinforcement, such as flashing lights or an animated toy.
Guidelines for Screening
Together with the American Academy of Pediatrics and other agencies, the Joint Committee on Infant Hearing developed Early Hearing Detection and Intervention (EHDI) guidelines. These call for completing the hearing screening (and re-screening, if a hearing loss is detected or the child does not pass the test) process by 1 month of age, performing a diagnostic evaluation by 3 months of age, provided a hearing loss is confirmed, and enrolling in appropriate early intervention services by 6 months of age. The Centers for Disease Control and Prevention terms this the "1-3-6 Plan."
The gold standard test used for diagnosis of hearing loss in infants and young children is testing the auditory brainstem response. Hearing thresholds can be estimated by recording the brain activity in response to tone bursts or clicks.
If hearing loss is confirmed, the test results are reported to the state EHDI office, primary care physician, and the state agency responsible for coordinating early intervention services. The child will be referred for a medical and otologic evaluation by a hearing healthcare professional trained in infant hearing loss. The family may also be referred to the state chapter of Hands & Voices, a nonprofit organization dedicated to supporting families with children who are deaf or hard of hearing.
It is imperative that parents inquire into whether or not their child was given a screening test before they leave the hospital following the baby's birth. Most likely, the test was given, but legislation varies state by state. Parents should receive documentation stating that the child passed the test or, if the child did not pass, information on next steps.
Technology Options
The three most important challenges identified by parents are communication, technology, and education. There is no one right answer regarding these issues, as every family and every child is unique. Monitoring progress and periodically reevaluating the needs of a child and the child's family are ongoing intervention strategies.
Technology helps the child hear sound and to learn listening skills in order to develop spoken language. Being able to hear is also a safety issue, such as being able to hear the beep of a car horn signaling its approach. Knowing the type, degree, and characteristics of the hearing loss will help the hearing healthcare team counsel the family about the best types of technology for their child. Technology options include hearing aids, cochlear implants, or boneanchored implants.
Pediatric hearing aids and implants include safety features such as tamper-proof battery doors; durability features like water resistance; and warranty, repair, and loss protection options. Some have LED power indicators, an on/off button to mute sound when the baby is sleeping, and come with kits that provide parents with tools (such as a battery tester) to care for the devices.
Kid-friendly accessories include safeguards to help keep hearing aids in place. Ear Gear markets itself as "hearing instrument armor" designed to protect against sweat, moisture, dirt, and losseven for babieswhile Tube Riders engages children with bright, bold designs to let them personalize their devices.
It's also important for hearing aids and implants to have direct audio input capabilities to ensure compatibility with FM systems, which wirelessly transmit sounds directly to the ear, and other external devices. These will become more important as the child enters school.
Hearing Aids
Hearing aids can be fit as early as 2 to 3 weeks of age. They work by amplifying sound and are suitable for all levels of hearing loss. Children fit with hearing aids before 6 months of age and who use them consistently often demonstrate language development skills comparable to their normal-hearing peers. Because hearing aid needs differ for children and adults, and also differ among children's age groups, they should be fitted by a hearing healthcare professional experienced with pediatric populations.
Practical and durable with relatively low repair rates, behindthe-ear (BTE) hearing aids are one of the most commonly fitted types for children. Most infants can use them and they are available for any degree of hearing loss, from mild to profound.
They are fit to the ear with a custom earmold, made by taking an impression of the ear. During the child's first year of life, rapid growth means the earmolds may need to be changed every month, but by the time the child reaches school age, earmolds are usually only changed every six months.
BTE hearing aids consist of a microphone, amplifier, speaker, and power supply. The unit attaches to the earmold with a tube. The majority of today's BTE hearing aids are digital and can be programmed for the individual listening needs of the child.
Among the hearing aids specifically designed for children, some of the most popular are the Oticon Pediatrics Safari, Phonak's Nios Micro and Naida, the Siemens Explorer, Starkey Pediatrics' children's models, the Unitron 360, and BABY440 from Widex. Hearing aids range in price from about $1,000 to $3,000 each.
Cochlear Implants
In some cases, children with a severe or profound sensorineural hearing lossthat is, "nerve" hearing loss involving the cochlea or the auditory nerve, or bothfail to make the expected progress with hearing aids. A cochlear implant can help.
Cochlear implants improve hearing by sending electrical signals directly to the auditory nerve, and they are approved by the U.S. Food and Drug Administration for infants as young as 12 months of age. They have external components (microphone, processor, transmitter, power supply) and internal components (receiver, electrode array). Surgery for cochlear implants is commonplace for most experienced otologists and otolaryngologists. Children are often discharged on the same day of surgery, and the surgery has a very high safety profile. The cost of a cochlear implant including surgery and post-surgery mapping appointments (to program the implant processor) ranges between $30,000 and $50,000, depending on how much rehabilitation is needed. Most insurance carriers cover the majority of the cost.
Currently, pediatric cochlear implants are available from Advanced Bionics (Auria, Harmony, and Platinum Series processors), Cochlear Americas (Nucleus 5 system), and MED-EL (Maestro). These instruments are FMcompatible and have direct audio input capabilities.
Bone-Anchored Implants
When a child has a malformation of the outer or middle ear that causes hearing loss and can't use a traditional hearing aid, a bone-anchored implant may be the best option. These devices conduct sound through bones in the skull, bypassing the outer and middle ear problem. The surgery for bone-anchored implant placement is commonplace and extremely safe. BAIs have external components (microphone, processor, power supply, and softband or ball cap or abutment when implanted) and an internal component that consists of the titanium implant. Boneanchored processors are fit to an elastic headband or ball cap for the first few years in life. By age 5, the skull bones have thickened and are strong enough for the surgical implant. The FDA has approved the implant in children age 5 and up due to the thickness of the skull.
Currently, bone-anchored sound processors are available from Cochlear Americas (Baha 3) and Oticon Medical (Ponto). The devices themselves cost about $4,000 each and with surgical fees up to $30,000; some insurance carriers cover these costs. Like cochlear implants, bone-anchored implants are FM compatible and have direct audio input capabilities.
As with any treatment, discussion with health care providers is the best way to determine the most appropriate plan for the baby. The array of hearing aid and implant digital technology processing options that have been developed over the past decade has drastically expanded the options for infants with hearing loss.
FOR MORE INFORMATION
Joint Committee on Infant Hearing
www.jcih.org
Early Hearing Detection and Intervention
www.cdc.gov/ncbddd/hearingloss/index.html
American Academy of Pediatrics
www.aap.org/healthtopics/visionhearing.cfm
Deafness Research Foundation
www.drf.org/Newborn+Hearing+Screening+NIDCD/
Centers for Disease Control and Prevention's Decision Guide to Communication Choices
www.cdc.gov/ncbddd/ehdi/ documents/Edmaterials/Decision-Guide.pdf (downloadable PDF)
Cochlear Implants:
www.cdc.gov/ncbddd/ehdi/cdrom/hearing_loss/cochlear_implants.html
Bone-Anchored Implants:
www.cdc.gov/ncbddd/hearingloss/treatment.html
Nannette Nicholson, Ph.D., is an associate professor and director of audiology in the Department of Speech Pathology and Audiology at the University of Arkansas for Medical Sciences in Little Rock. She has a joint faculty appointment at the University of Arksansas at Little Rock and a clinical staff appointment at Arkansas Children's Hospital.
Joshua Spann is a doctor of audiology student in the department.
