US research finds that two cochlear implants are better than one
4 August 2008
A recent study of cochlear implant patients seen by Indiana University School of Medicine physicians is the first to show evidence that having cochlear implants in both ears significantly improves quality of life in patients with profound hearing loss, and that the cost of the second implant is offset by its benefits.
The study, conducted by Dr Bradford Bichey and colleagues, found that improvements in factors contributing to quality of life – including such critical abilities as hearing in noisy environments, focusing on conversations and speaking at an appropriate volume – resulted when cochlear devices were implanted in both ears.
Twenty-three severe to profoundly deaf adults completed a range of assessments at three points in time: before their first cochlear implant, after their first implant, and after their second cochlear implant was in place. Scores were obtained to measure quality of life in areas including cognition, emotion, pain, speech and hearing, and a ‘cost-utility’ score was obtained by comparing the quality of life score to the actual cost of double-implantation. The cost-utility score was used to assess the merit of two implants compared to one.
"There is definite improvement after one implant and there is a significant added bump in sound and speech perception after the second implant. Emotional well being improves. And we found a favourable cost-utility analysis,” said senior study author Dr Richard Miyamoto. "We didn't know that cognitive skills and emotional issues would so significantly improve with the implantation of a second cochlear device. In addition to the physiological improvements we saw in patients who had bilateral implants, we found that patients were able to function better in noisy environments and definitely felt better about themselves."
However, because the study only included patients who were using both implants at the time of the research, it will have missed any people who preferred to use a single implant, switching off the second one. Including these patients may have reduced the level of benefit found. In addition, the differences between the US and UK health care systems mean that an accurate UK cost-utility analysis would need to include the continued cost of maintaining the implants long-term.
Deafness Research UK is currently supporting a study of using one versus two cochlear implants in profoundly deaf young children, at The Ear Foundation in Nottingham.
