Cochlear implants: one man’s experience
Recently, I was lucky enough to meet Tom Rice. Tom received a cochlear implant in October of 2013 and is open to sharing his nearly life-long experience with hearing loss. I am indebted to Tom for his willingness to talk about his experience and I stand in complete admiration for his generosity. I also want to thank Marlon Aguilar for producing the video shown below.
I will make a few comments and then let Tom speak for himself. In the first segment, Tom talks about realizing that he was losing his hearing. The changes that he experienced in his late teens and twenties were slow and symmetrical. Hearing loss did not interfere with his life until his late twenties when he first got hearing aids. Tom’s story reminds me of how hard it can be to realize hearing loss even when it is more sudden. David Wright was a South African poet who contracted scarlet fever when he was 7 years old. He wrote a book, Deafness (Harper Perennial, 1994), which I highly recommend. In the first portion of this book, which is an autobiography, he writes, “One would think that deafness must have been self-evident from the first. On the contrary it took me some time to find out what happened….One day I was talking with my cousin and he, in a moment of inspiration, covered his mouth with his hand as he spoke. Silence! Once and for all I understood that when I could not see I could not hear.” In Tom’s case, if someone was talking right to him, he could make out what was said by using all available cues – auditory, lip movements, facial expression and context.
As Tom got into his forties, his hearing continued to decline. And Tom’s hearing loss became a problem whenever he was not in one-on-one situations or in very small groups. In other words, if Tom could not use lip reading, understanding was going to be a challenge. Tom’s hearing loss has been a progressive loss starting from the highest frequencies. Losing the ability to hear high frequencies is common. In fact we all hear higher frequencies at birth than we do by the time we reach our mid-twenties.
The age-related hearing loss of the very highest frequencies has been used both to teenagers’ advantage and disadvantage. To their advantage, teenagers can set their cell phones to use high frequency rings. Teachers, even those in their twenties, cannot hear these frequencies and so the teenagers can get calls without teachers’ knowing it. On the other side, shop owners who want to discourage teenagers from hanging around their stores, can play high frequency sounds that will drive younger people away. The owners as well as the older preferred customers cannot hear the high frequency sounds and therefore are not bothered.
What led to Tom’s hearing loss? Probably a loss of outer hair cells. Remarkably these hair cells are not the sensory cells that connect to the auditory nerve. Instead outer hair cells move the cochlea, increasing the stimulus that inner hair cells are exposed to. Without the mechanical amplification provided by the outer hair cells, inner hair cells do not respond to sounds at reasonable intensities (meaning they could respond to a jet engine 10 feet away but not to sounds of less than about 120 decibels).
Tom received a hybrid cochlear implant, an exciting device pioneered by his physician Dr Bruce Gantz. This device allowed Tom to keep intact the apex of his cochlea, where low frequency sounds are processed. Dr Gantz could thread a wire into the base of the cochlea and then push it only part of the way into the cochlea.
The cochlea has a tonotopic arrangement, meaning that tones are represented in topographic progression from the highest frequencies at the base to the lowest frequencies at the apex.
One of the truly remarkable features of Tom’s story is how quickly he regained his hearing after his implant was turned on (a month after surgery to allow for inflammation to resolve). Tom regained hearing quickly because he had so much previous experience with hearing – 17 years or so before there was any problem. I am sure that this metaphor is hyperbole but I get the sense that Tom’s ability to use his cochlear implant was akin to a person using a knee replacement. Plug it in and go. In contrast, Michael Chorost, an author who lost his hearing as an infant and never heard normally, had a much harder time learning to use his cochlear implant. In his memoir (Rebuilt: My Journey Back to the Hearing World, Houghton Mifflin, 2005), Chorost describes having to be a perceptual Olympian to be able to understand the electrical signals from his implant.
One of the reasons I find Tom’s story is so fascinating is that he speaks a hearing person’s language. He can tell us that the cochlear implant sounded like wind chimes at first. Someone who was profoundly deaf from birth or even from an early age would not be able to translate the electrical signals into perceptions that hearing people are familiar with. Because of Tom’s long experience with normal hearing, he quickly gained great benefit from his cochlear implant. And he can tell us that the hearing provided by his implant is still not normal. For example, Tom realizes that that sound at the end of “boat” is a t, a sound he had not heard for a long time before his implant. At first the sound at the end of boat did not sound like a t, but after some time, Tom’s brain has re-assigned that sound to be a t.
Tom’s hearing is not normal. He still has problems in environments with background noise. The telephone (the gold standard for hearing because it depends only on auditory cues) is challenging. Heavy accents are hard work. Music is enjoyable but it’s not as he remembers it.
Overall, receiving a cochlear implant has been a “game-changer” for Tom. He tells the story of hearing but not understanding whispering when he was young, one of the early signs that his hearing loss was becoming a problem. Now after receiving a cochlear implant, he no longer has to be facing someone to hear them. He can now overhear. That is a big deal. Barbara Stenross writes in Missed Connections: Hard of Hearing in a Hearing World (Temple University Press, 1999) that one of the most impactful problems of hearing loss is the inability to overhear. A great deal of important social information is garnered from overhearing.
[Note added: As I was responding to Dan below, I just came across this perfectly put quote from Michael Chorost’s book: “Social norms are not taught, they are overheard, but the one thing even the most skilled deaf people cannot do is overhear.”]
Hearing Tom say that the walk to get the paper is now “filled with sound” is just priceless. How wonderful.
Enjoy Tom’s story in his own voice:
Are you aware of any research or other data related to choclear implants in children profoundly deaf at birth and later behavior?
Babies who are born deaf can develop near normal hearing if they receive cochlear implants early. In congenitally (= at birth) deaf babies, time is of the essence. Those that receive implants before the age of 2 do better than those who receive implants between the ages of 2 and 4 years. Beyond 4 years old or so, the possible benefits fall off steeply. Let me explain why. We have developmental periods of time when we are ripe for learning certain functions. For example, a baby learns her native tongue without sitting in class or hitting the books. While some people may be facile at learning languages as adults, no one can rival a baby in language acquisition. [I remember the vacation when I first met my French-speaking nephews who were roughly 2 and 4 years old at the time. We all arrived on a Thursday. My nephews had never heard or spoken English and I was making do with high school French. By Sunday, their English was better than my French.]
Periods when we are ripe to learn are termed critical periods. There are critical periods for language acquisition, vision and hearing. Other critical periods are postulated but less certain. In any case, the window for learning to see or hear opens and then shuts like a door on an spring-loaded closer. The key to implanting cochlear electrodes into babies is to do it when they are young and can learn to hear with the signals provided by the implants. A congenitally deaf child that receives cochlear implants as a teenager will never hear (=meaning understand sound/language) just as a baby born with congenital cataracts will never see if those cataracts are removed during adulthood. If we miss hooking up our brains during hearing and seeing critical periods, we cannot make up for it later.
Congenitally deaf babies are typically given two cochlear implants, one in each ear. This is the only way that they can learn to hook up their auditory system normally, so that they can both understand speech and figure out who is speaking. Having bilateral hearing even helps in the development of normal vision, of for example moving objects. This makes sense as moving objects make sound; receiving the same message of motion from two sensory modalities is reinforcing, and therefore helps with proper hook-up.
What happens in babies that remain deaf until older ages? Well it turns out that their auditory pathways change in profound ways. For example, the auditory cortex is reduced in size. Neurons that remain in the auditory cortex become hyper-excitable, firing at the slightest input. You can read more about the changes that happen in this open access review:
Using the above information, we can better understand the very different experiences of Tom Rice and Michael Chorost. Tom had normal hearing until at least age 17 and even after that, he had normal hearing. In contrast, Michael Chorost was deaf until at least age 2½. Tom’s brain was all hooked up and ready to go after his 15-year break ended thanks to a cochlear implant. Michael Chorost’s brain was never as well hooked up as Tom’s. He played catch-up when he received his cochlear implant decades later. Essentially, Michael Chorost was trying to do in his 30s what most of us did effortlessly and unconsciously as 1-2 year old babies. Ergo, his feeling that he needed to be a perceptual Olympian.
Finally, there are certain criteria that must be met in order for a cochlear implant to be warranted. First, the problem must me in the cochlea (sensorineural hearing loss) and not in the external or middle ear (conductive hearing loss). Second, the auditory nerve fibers must be working and intact. In the case of a baby, there must be a supportive environment to nurture the baby’s learning to hear.
Providing cochlear implants to congenitally deaf babies is a highly emotional topic in the deaf community. I hope that we can all support parents as they make their decisions, knowing that in this case one answer does not fit all. My belief is that the only job of those of us who are not in the shoes of the parents is to support the parents’ decisions and love the baby.
Thank you for the quick response. I expect I shall find the Butler/Lombar article especially useful once I have digested it.
Thanks for doing this article. Because of your article I read Rebuilt. It was a helpful read. I am currently waiting on eligibility evaluation for Hybrid Cochlear Implants and furiously researching information so that I can ask informed questions and follow the process. I hope you will continue to research and write on this topic
Please keep in touch. I’d love to know how your implants work. Are you going to U Iowa?