Cochlear implants can improve speech and quality of life in adults with
severe hearing loss, according to a new analysis of past studies - and two
implants seem to work better than one.
The implants, which are surgically placed into and behind the ear, transmit
sound directly to the auditory nerve.
"Cochlear implantation is just a hugely beneficial procedure for the people
who need it. It's almost like magic," said Dr Pamela Roehm, an otolaryngologist
from the NYU Langone Medical Center who wasn't involved in the new study.
"Their hearing isn't completely normal, but for speech (and) understanding,
it's so good," she said.
According to the National Institutes of Health, about 17% of American adults
have some degree of hearing loss, and the chance of becoming hard of hearing
increases with age. Only those with severe hearing loss or deafness, for whom
hearing aids haven't worked, are considered for cochlear implants.
The new analysis included 42 studies that compared hearing, speech and
quality of life in eligible adults before and after they received a cochlear
implant, or compared having one versus two functioning implants.
Those studies used a range of tests over different time periods to measure
the effects of implantation, so it was difficult to compare them directly,
researchers led by James Gaylor from Tufts Medical Center in Boston. However,
almost all trials looking at the effect of a single cochlear implant showed that
people's speech and quality of life improved after implantation.
Among studies comparing one versus two implants, the majority also found
participants were better at communicating and localising sound when they had a
cochlear implant in each ear. It wasn't clear how much of an effect a second
implant had on their quality of life, however.
Cochlear implants cost about $50 000 each, which is covered by most insurance
providers. Through 2010, approximately 43 000 adults and 28 000 children had
received an implant in the US. Possible complications of implantation include
infection or damage to the device. But Roehm said all things considered, it's a
pretty minor procedure.
"It's surgery - you have to have general anaesthesia - but as surgeries go,
it's not very risky (and) you don't lose a lot of blood," she said. She and her
colleagues have implanted people over 90 years old, Roehm said, with good
results. The implants aren't perfect - they may help people communicate better
in person and on the phone, but they don't always allow them to listen to music,
for example, she noted.
The new findings don't mean that deafness has a detrimental effect on quality
of life, said Gaylor. He added that for some in the deaf community, cochlear
implants are still controversial.
"Our hope is that this paper will allow providers, payers, and most
importantly patients to ... make more informed decisions about cochlear
implantation," Gaylor wrote.