Cochlear Implants Found To Help Deaf-Blind Patients

But a new University of Michigan Health System study suggests that, contrary to expectations, the deaf-blind can indeed regain significant ability to recognize speech. The authors report significant improvement in eight deaf-blind patients who received a cochlear implant -- a device that translates sound into electrical impulses that are delivered directly to the inner ear.

While tens of thousands of deaf people have received cochlear implants, the devices haven't traditionally been seen as appropriate for deaf-blind patients. This is because significant numbers of deaf recipients still benefit from visual clues while using their implants to help them understand speech. But in fact, the group of deaf-blind UMHS patients did even better at speech perception after implantation than a comparison group of deaf patients, according to their case histories in a paper in the January Journal of Otology and Neurotology (formerly the American Journal of Otology.)

"These patients need every stimulus they can get, and cochlear implants seem to produce a significant impact on their ability to comprehend the world despite multiple sensory deficits," says lead author Hussam El-Kashlan, M.D., a UMHS cochlear implant surgeon and assistant professor of otolaryngology. "It also appears that the positive effect is greatest in those who receive their implants earliest."

The research finding comes from analysis of UMHS patients who had already lost most or all of their hearing, either before or after they learned spoken or sign language, and then began to lose their vision. All eight received a cochlear implant and substantial rehabilitation therapy at UMHS, and took tests before and afterward to measure their speech perception.

To date, the study is one of only two of its size to examine the effect of cochlear implants in people with multiple sensory deficits, as the condition is often called. The other looked at blind people who went deaf later in life.

In a comment published alongside the UMHS paper, British expert Richard Ramsden notes that the UMHS study "lends support to the increasing feeling that patients who suffer from…deafness and blindness may be very good candidates for cochlear implantation."

As many as 40,000 Americans are deaf-blind. Many still communicate via the same methods - finger spelling and Braille hand writing - as the most famous deaf-blind person in history, Helen Keller. And like Keller, many lose their senses either together or separately due to diseases in their genes, the womb or during childhood.

Two of the U-M patients in the study had Usher's syndrome, a common cause of deafness accompanied by a progressive vision loss due to retinitis pigmentosa. Two others had sensory loss thought to result from TORCH syndrome, which affects the babies of women who contract German measles, or rubella, while pregnant. Two others had genetic syndrome