Sensorineural hearing loss, a big problem: help for some may be on the way

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Tradtl. Hearing AidAbout 20 percent of adults in America have some degree of hearing loss that s almost 50 million of us. By age 65, one-third of us have hearing loss sufficient to interfere with normal activities that s the third leading physical condition to do so, after heart disease and arthritis. Noise and aging are the most common causes. While hearing aids can help most people with mild to moderate hearing loss, severe hearing loss is largely resistant to such simple measures.

The most common type of hearing loss is sensorineural, caused by damage to the inner ear (the cochlea). High-frequencies are the first to go, often accompanied by tinnitus (ringing in the ear), which can itself be disabling. As hearing impairment progresses, employment performance is also affected, causing job loss and lower wages among the employed, along with reduced enjoyment of life.

The FDA recently approved the first implantable device for this type of hearing loss, called the Nucleus Hybrid L24 Cochlear Implant System. The device combines the attributes of a typical hearing aid with a cochlear implant. The electronic device consists of an external microphone and speech processor that picks up sounds from the environment and converts them into electrical impulses. The impulses are transmitted to the cochlea through a small bundle of implanted electrodes, creating a sense of sound that the user learns to associate with the mid- and high-frequency sounds they remember. The hearing aid portion of the device is inserted into the outer ear canal like a conventional hearing aid, and can amplify sounds in the low-frequency range.

The study the FDA reviewed before approving the device involved 50 patients with severe high-frequency hearing loss, who maintained some degree of low-frequency hearing. Of this group, a majority reported increased word and sentence recognition at six months after implantation. However, two-thirds also experienced adverse effects: these included reduction in low-frequency hearing, tinnitus, dizziness, and need for another operation (6 patients). The FDA decided these problems were outweighed by the overall benefits for patients whose problem did not sufficiently improve with traditional hearing aids.

ACSH s Dr. Gil Ross had this comment: While severe hearing loss is a huge problem, this device is not exactly a panacea, given the far-from-overwhelming fraction of patients benefiting and the rather high risk of adverse effects. Still, I agree that this represents a valid option for those who don t get satisfactory results from a traditional hearing aid. I also wonder how much this is going to cost, especially since most of the users will be in the senior age group?