Stem Cell Breakthrough

There is promising news in stem cell research for people with hearing loss.  Heller Laboratory at Stanford University is reporting that after 10 years of work in their lab, they have

“found a way to develop mouse cells that look and act just like the animal's inner-ear hair cells—the linchpin to our sense of hearing and balance—in a petri dish.”

This is a huge step towards being able to restore hearing naturally in people with damaged inner-ear cells.  As I have written about before, birds are able to regenerate their damaged inner-ear hair cells so they are never rendered permanently deaf, but mammals do not have this ability.  Researchers studying chicken cochlea realized that if they could use stem cells to regrow the hair cells in the cochlea of mammals, then they could work towards restore hearing in people with hearing loss.  Today, we’re one step closer!

This is what Brandt had been hoping for (and counting on) for many years, before we found out last year that his hearing would be gone long before stem cell therapy would be available.  Although we are excited that Cochlear Implants are a viable option to replace his hearing soon, we’re still hopeful that he can someday experience real, natural hearing through stem cell therapy.  (It would also require gene therapy—tracking down which genes are damaging his hair cells and ‘fixing’ them—but we won’t worry about that right now…)

I can’t help but wonder what the reaction will be in the Deaf community.  One of the arguments I have heard from the Deaf against Cochlear Implants is that it does not restore natural hearing, it ‘merely’ replaces hearing through digital codes that stimulate the auditory nerve.  The CI user, so the argument goes, is still deaf—once the CI processor is removed, they still can’t hear anything (the surgery wipes out all residual hearing).  And since the processor provides a computer’s digital rendering of sound, it is not the same as ‘real’ hearing.  It often takes many, many months for the CI user to learn how to hear with the implant.  There are also risks with the CI implantation surgery itself to consider. 

Stem cell therapy, however, would actually provide real hearing—and undoubtedly without near as much risk.  So while this is wonderfully promising news for the millions of people with hearing loss who want their natural hearing back, it may well push Deaf culture closer to the brink of extinction.  It’s a dilemma I’ll leave to explore another day; and we’re still several decades (at least) before stem cell therapy would be available for the general public.  But it is an issue that will become a reality soon enough, and something that will affect our children and grandchildren if it does not fully affect us.

  

What the Future Holds (or, Inside the Gray Area)

There is no such thing as a deaf chicken.

I know that sounds like the punchline to a joke, but it’s true! Birds have the ability to regenerate damaged inner hair cells in their cochlea, making them unable to become permanently deaf. Brandt and I learned all about chicken cochlea last June at HLAA’s annual convention in Nashville, in the Research Symposium “An Update On the Latest Hair Cell Regeneration Research” presented by the Deafness Research Foundation.

The Research Symposium was the main reason we wanted to attend the convention, because Brandt had been told for many years by “Dr. Smith” that stem cell therapy was his only hope. Just two months before the convention, last April, Dr. Smith told us that Brandt would never have to worry about getting a Cochlear Implant because he wouldn’t go deaf for another 20 years, and by then he could just get stem cell therapy to re-grow his damaged inner ear hair cells. WRONG on so many levels, Dr. Smith!

First of all, as we found out last May from Dr. Awesome, Brandt will probably be deaf in only five or six more years, making Cochlear Implants his only possibility for immediate replacement of his hearing (but we still held on to Dr. Smith’s promise of natural, restored hearing in 20 years). Second, as we found out later, stem cell therapy is a lot more than 20 years away. And third, Brandt is probably not even a candidate for it!

Imagine our shock and disappointment when the researchers explained that stem cell therapy was probably another 40 to 60 years away from public availability, and that people with genetic hearing loss like Brandt are NOT good candidates for it. Because his inner ear hairs are being damaged by internal, genetic causes, the gene(s) causing it would first have to be identified and eradicated from his body. Otherwise, if he received stem cell therapy and had his hearing restored, the ear hair cells would just be killed off by the faulty genes again. Good candidates are people whose hearing loss was caused by an environmental factor, such as exposure to loud noise or ototoxic medication, like my Aunt Louise.

Fortunately, the Hearing Loss Gods were smiling on us that humid weekend in Nashville, and Brandt discovered just how amazing Cochlear Implants are.

Cochlear Implants are very different from hearing aids. Hearing aids just amplify a person’s residual hearing. CIs replace a person’s natural hearing, bypassing the damaged inner ear and sending sound—in the form of electronic signals—directly to the brain. Cochlear Implants consist of 2 main components, one internal and the other external. The internal component is surgically implanted onto the skull, and its electrode array is placed inside the cochlea (don’t worry, nothing comes into contact with the brain itself). The electrodes stimulate the auditory nerve and send the information to the brain, which interprets the information as sound. The external component is the sound processor, which is worn either on the body, or like a large Behind-the-Ear hearing aid. Microphones on the processor pick up speech and other sounds. The headpiece has a magnet that connects the external processor to the internal implant. Advanced Bionics has a short (and captioned!) video that explains how the CI works.

The main drawback to a Cochlear Implant is that in most cases, it wipes out the recipient’s residual hearing, making them completely deaf when the processor is off. This is why we have to wait until Brandt loses more of his residual hearing before he can get a CI. He is still considered “in the Gray Area” of being a CI candidate because his Word Recognition Scores dropped from 100% to 24% in only 6 years. Even without a detailed explanation of Word Recognition testing, you can guess how significant a 76% drop in speech discrimination is.

We don’t know how long we will be stuck in the Gray Area, impatiently waiting for more hair cells in his cochlea to die off, further impacting his ability to hear and process speech. The cruelty of this situation is that I am in effect wishing that my husband goes deaf, suffers more social embarrassment, misunderstandings, and frustrations, in the hopes of someday achieving CI Candidacy status. I have seen how happy Cochlear Implant recipients are; not only my Aunt Louise, but every CI user we have met tells us, “Don’t wait, I wish I’d had this years ago, it has changed my life!” When they ask us the inevitable question, “What are you waiting for?!” the answer is simply, “To get out of the Gray Area.”