Some researchers are looking into fixing the mutation itself through gene therapy. In experiments, the altered gene is delivered to the relevant cells using a modified virus. That sounds simple enough, but the reality is much more complicated — there are hundreds of genetic mutations that can cause deafness, so researchers have to make sure they're targeting the right ones and that they're doing it in the right cells.
The researchers are still figuring out exactly when this kind of therapy would be the most effective (it would likely be at a very young age, as the cochlea degenerates over time in people with hereditary hearing loss). Several researchers, including Moser's group, have already been able to dramatically restore hearing in deaf mice over a period of several months. But Moser said that because there are so many genes that can cause hearing loss, any specific gene therapy may only be applicable to a small percentage of cases. In order to use gene therapy to make a big dent in the number of hereditary cases, scientists need to have the ability to edit hundreds of genes. That's not possible with much specificity yet, Moser said.
All these advances can drastically improve the quality of people's lives, but quick fixes for hearing loss are not coming soon, in Heller's estimation. "I don't think there's something on the horizon, whether it's a technological device or a drug, that will provide an immediate cure," he said. Indeed, nearly all the researchers stressed that most of these technologies will not be available to the general public anytime soon. They said press coverage typically leads to dozens of letters from patients volunteering for research into these techniques, and they usually have to tell people in search of hearing help that the techniques are not yet ready.
Heller expects that progress will be step-by-step. First, diagnostics will greatly improve over the next few decades, followed by breakthroughs in hearing aids and cochlear implants, drugs and maybe gene therapy. It's not clear which will come first, and it could take as long as 100 years, but chances are, the deaf and hard of hearing will have many more options than they do now.
"It's an exciting time to be working on hearing restoration," Moser said.
— By Alexandra Ossola, special to CNBC.com