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July 30, 2003

Ear Implants Linked to Child Meningitis Risk in Study (Update1)

From: Bloomberg - Jul 30, 2003

July 30 (Bloomberg) -- Implants that help deaf children hear also may put them at a 30-fold higher risk for bacterial meningitis, a deadly infection of the brain and spinal cord, according to a study in the New England Journal of Medicine.

Australia's Cochlear Ltd., and closely held Med-El Corp. of Austria and Advanced Bionics Corp. of Sylmar, California, make the devices that have revolutionized treatment for severe hearing loss in the past two decades. The implants, which cost as much as $60,000, translate sound into electronic signals that allow deaf children to hear and learn to speak.

Advanced Bionics recalled one implant, with an extra piece known as a positioner, in July 2002 after reports of meningitis. The new study found potential risks for all the devices, especially for patients with positioners or malformed inner ears.

''We saw an increased risk in children with any type of cochlear implant,'' lead researcher Jennita Reefhuis said in an interview. Parents ''should watch carefully for any signs of bacterial meningitis'' and seek immediate treatment, she said.

Twenty-six of 4,264 children who got the implants from 1997 through August 2002 while under age six subsequently developed meningitis, according to the research by the U.S. Centers for Disease Control and Prevention. Six additional children have since developed the condition. Less than one case would normally be expected among children under six, the CDC researchers said.

Higher Risk?

The study doesn't prove implants trigger meningitis, said Jeff Greiner, president of Advanced Bionics, in an interview. While those with positioners clearly put children at risk, others may not cause harm, he said. Meningitis is more common in deaf children, who often can't hear because of a previous bout with the illness or have misshapen ear anatomy, he said.

''The study confirms the wisdom and prudence of what we decided to do with a minimal amount of data a year ago,'' when the company took positioners off its device, he said. ''And it reemphasizes to parents of cochlear implant users and doctors the importance of vaccination, aggressive treatment of ear infections, and education about the symptoms of meningitis.''

Another study, comparing meningitis rates among deaf children with implants to deaf children without the devices is needed to see if there is indeed an association, he said.

Possible Causes

Doctors speculate that bacteria causing ear infections may spread to the spinal cord and brain around the devices in some cases, causing meningitis. Signs of the disease include high fever, stiff neck and nausea or vomiting, which can be fatal if not treated quickly.

Positioners may increase the child's risk of meningitis by damaging the delicate structures of the inner ear, Reefhuis said. In other cases, the tissue may not heal properly to completely seal the hole created between the middle ear and inner ear to accommodate the device, she said.

Experts in hearing loss emphasized that the devices are the only option for many people who want to hear. About 1 million Americans are candidates for cochlear implants, wrote George A. Gates from the University of Washington and Richard T. Miyamoto from Indiana University School of Medicine in an editorial.

''For most adults and children with severe-to-profound hearing loss, the use of an implant is the only viable choice for effective oral communication,'' Gates and Miyamoto wrote. About 60,000 people worldwide, and 10,000 children in the U.S., have the implants, they said.

Officials at Cochlear Ltd. and Med-El didn't return calls for comment on the study findings.

Shares of Cochlear Ltd., the largest maker of the inner-ear hearing devices, fell 18 cents to A$33.80 in Wednesday trading in Sydney. The company boosted sales of its products when Advanced Bionics redesigned its implant last summer, pulling it from the market for six weeks.

Patients who opt for a cochlear implant must get vaccinated first to ward off disease, health officials said.

''Most bacterial meningitis is vaccine-preventable, so children who have a cochlear implant, or who will receive one, should have all recommended childhood vaccines,'' CDC Director Julie Gerberding said in a statement.

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