HybridWords
--Hybrid Implants on the Horizon: Shorter Electrodes are Helping More Hear--
In a research lab in Iowa, otolaryngologist Bob Gantz is destroying the cochlea. His cochlea-crushing moves aren’t hindering hearing, however, but helping it. That’s because “the ear,” as Gantz explained “is a forgiving organ,” a fact which scientists too worried about ruining its inner microstructure have not previously understood. They fear that snaking electrodes of cochlear implants into the cochlea destroys whatever hair cells still live there, causing complete hearing loss. Gantz, on the other hand, has dared to poke short electrodes into the cochlear space, and he’s shown that he can obliterate its outermost parts without disturbing the function of the hair cells deeper within the ear. This insight has allowed the University of Iowa scientist to develop a promising new cochlear implant, called the hybrid implant, which combines short electrodes with a familiar device—the hearing aid. Gantz’s invention blends the best of bionics with acoustic hearing to benefit a unique population who could not be helped by implant or hearing aid alone: people with high frequency hearing loss.
Hearing loss depends directly upon the health of hair cells in the cochlea. These microscopic cells, housed along the snail-shaped inner ear, pick up vibrations and convert them into electrical impulses that the brain recognizes as sound. Hairs in the deepest part of the cochlea pick up low-frequency sounds, such as music. Hairs at the cochlea’s entrance pick up high-frequency sounds, including speech. People who are profoundly deaf, like those who wear cochlear implants, can hear neither high nor low-frequency sounds on their own because the majority of their hair cells are damaged.
But complete hearing loss, affecting all the hair cells, isn’t the only type. With age-related hearing problems, for example, or with hearing loss suffered by Iraqi soldiers exposed to relentless gun fire and bomb blasts, not all hearing wanes. Rather, these people tend to lose high-frequency hearing first, meaning their inner hair cells are still intact. While most vowels are in the low frequency range, most consonants are high frequency sound bites, and as such, get distorted or lost for such patients. As specific consonants disappear, individuals can no longer discriminate a “g” from a “t,” for example. And since consonants are the milestones of speech, breaking up words which would otherwise be streams of squishy vowels, people with high-frequency hearing loss have great difficulty with speech understanding. They lose more and more words, until they’re unable to make sense of entire sentences.
For this group, whose only problem is detecting high-frequency sounds, a regular implant is a problem. Its far-reaching electrodes destroy hair cells deep within the ear, eliminating any ability to hear low-frequency information naturally. And even though the implant does step in and provide low-frequency hearing, it is a shackle compared to the cochlea, which, lined with thousands of hair cells, does a far better job of allowing people to hear low-frequency tidbits like music or the pitches in voice that distinguish one speaker from another. Thus, preservation of normal hearing is often preferable to the rougher sound estimates of a surgical implant for patients with residual heairng. But so far, there’s been no way to address patients in this middle ground—to allow them to enjoy the richness of sound through the low cochlear zones that are still working, while compensating for the high-frequency dead zones. These people have had to trudge through life not with implants but with hearing aids, which don’t clarify sound, but simply amplify it. And hearing aids turn up the volume for all sounds, not just speech. “But you could use the hearing aid to make the sound as loud as you like,” Gantz explained “and if you filter those consonants out, the sound still doesn’t make sense as words.” This has made for a disgruntled population of hearing-impaired patients—those who get nervous and depressed at social funtions because they cannot make out words, especially amidst heavy background noise.
Now, Gantz has the solution: make the electrode shorter, so it substitutes only for the hearing that’s already lost. Pair the short implant with a regular hearing aid to amplify the remaining low-frequency hearing, and people with high-frequency hearing loss just might hear again more like they did years earlier.
This resolution seems simple. But the idea to use shorter electrodes to selectively help hearing would certainly not have evolved so soon had Gantz not been willing to take a chance. “Electrodes were seen as risky. Once you start pushing them into the first turn in the inner ear,” Gantz explained, “there is a tendency for these wires to ride right into the sensitive scala media (a fluid-filled sack within the cochlea), meaning you disrupt the hairs cells attached to it and lose all residual hearing.” But Gantz believed that with calculated intrusion, hair cells in the depths of the ear would forgive a little interference. His courgae to explore this notion—to pry and poke in the cochlea—was fueled by observations of the work of a man who had dared to do it with cats, continents away in Australia.
At the Bionic Ear Institute in Melbourne, Robert Shepherd had been testing the fortitude of hair cells since the early 90’s. “I came across Shepherd’s work in a literature search,” Gantz said. “Before I knew about it, I had the concept myself that you could damage some hair cells and the rest would be okay, but I knew I was going to have to do animal studies before I could take this to patients.” Gantz found that Shepherd had already done such studies—the first of their kind—in cats. The Australian’s work involved winding electrodes into the ears of hearing kittens, whose hair cells were fully in tact. “I contacted Shepherd,” Gantz said, “and he told me about the kitten study. Basically, where he put the electrodes, the hair cells were a little bit damaged, but when he went deeper into the cochlea, the hair cells were still okay.”
Shepherd’s promising results in animals were a springboard for Gantz’s eventual work in humans. The Iowa physcian used the Australian scientist’s data “to convince the FDA that there was a possibility we could actually do human studies.” Gantz’s efforts were especially important in light of changing candidacy for cochlear implantation. “Hearing specialists were and are continuing to implant not merely the profoundly deaf, but also deaf people with more and more residual hearing,” he said. “But as you implant these patients, you hurt their remaining low frequency hearing—their music perception, or their ability to distinguish voices.”
By targetting only high-frequency hearing then, Gantz was hoping to avoid this. Ideally, his efforts would help not just a select group of patients, like older folks or Iraqi soldiers with specific high-frequency hearing loss, but also cochlear implant candidates who retained some low-frequency hearing and could benefit by keeping it. “Residual ability to hear is often better than what the implant provides,” Gantz emphasized. In everyday life, problems associated with relying on implant-generated low-frequency hearing are manifest at parties, business meetings, large events, anywhere where more than one voice—differentiated by a slight change in a low-frequency pitch—is presented to a patient. “Patients with cochlear implants always complain that they can’t hear speech in noise,” Gantz said. That’s because the implant doesn’t provide them enough pitch options to distinguish one voice from the next. In a crowd of talkers, many voices may resonate at the same pitch, leaving implant users clueless and frustrated. Hopkins neuroscientist David Ryugo also frequently hears this complaint. “People with hearing problems in noisy places get pretty depressed,” he said. “They might just go sit alone at a table somewhere to get away from the noise or to have a one-on-one conversation.” The physician in Gantz wanted to use his shortened electrode to stop this, to help patients who were going to get implants anyway to keep the best of what they had—their residual ability to detect sound. The scientist in Gantz was ready to explore every possible means of cochlear manipulation to make this a reality. “It’s really a balancing act,” he said, “of where the implant is better versus trying to save the residual hearing.”
In the late 90’s, Gantz began experimenting with act of balancing. He tested with a short electrode which extended only 6millimeters into the cochlea, compared to the standard 24. Gantz’s first test group was a population of subjects with little residual hearing. “I think the 1st group of 6mm subjects had only 10-15% word understanding,” he recalled. By doing trials in these patients, whose hearing abilities were nearly as bad as the profoundly deaf who regularly received full-spectrum implants, Gantz reduced risk. If he were to destroy their residual hearing, they hadn’t started with much anyway. Furthermore, in case his patients did lose this low-frequency ability, which would require them to receive full-spectrum implants, Gantz’s team had prepared a special secondary back-up electrode that could be inserted at the standard distance of 24mm into the ear, right beside the shortened version. His bases were covered.
But Gantz didn’t have to use the back-up. His study was a success. “The most important thing that we learned using the 6mm device,” Gantz said excitedly, “was that we could keep the hair cells of the inner ear alive when we used a short electrode! We knew because we preserved our patients’ voice discrimination just the way it had been for them before their operation.” This was the first time that hair cell plasticity had been demonstrated in humans. “Unfortunately,” Gantz explained, “we did not publish our results since we were trying to get enough data to submit to a high impact journal like Science or Nature. Both publications thought this study was too focused and needed to go to a journal with a speciality.” So Gantz’s work did not see print until 2003. He did present the concept, however, at the 10th anniversary of the National Institute of Deafness in October of 1998.
So far, about 60 patients have received the hybrid implant, manufactured by Cochlear Corporation. About 10 have had it for more than a year. “The device is still in clinical trials but initial results have wowed us,” Gantz said. He’s referring to patients’ ability to understand words. “We have a special test for word understanding,” Gantz explained. “And it’s the most difficult test we can do. We test with words that are monosyllabic.” Gantz explained that when you hear a word in the context of a sentence, “you get a lot of info from the context and you could guess at the words you don’t hear.” But when you hear a monosyllabic word alone, not only is there no emphasis on one syallable or the other, but there’s no context. A patient who can understand such words demonstrates that the hybrid is truly clarifying consonants. And it appears that it is: a year after the surgery, hybrid implant recipients are understanding an average of 70 percent of the words in standard hearing tests—up from 25 percent before the operation when they may have relied soley on hearing aids.
And the combination of bionic and acoustic not only beats a hearing aid, but a regular implant, too, which permits patients to understand just 50% of the words thrown at them in a hearing test. Gantz said that it will be important for some full-spectrum implant wearers to make the transition to hybrids. “Right now,” Gantz said, “a lot of people with 10-15% residual hearing are getting regular implants. They’re going to lose significant low-frequency hearing that way.”
While hybrid implants have proven successful in trials, they’ve not yet been approved by the FDA. Meanwhile, Gantz continues to receive funding from Cochlear Corporation. The Australia-based implant manufacturer waits in the wings for Gantz’s device to be market-ready. “The hybrid implant is a potential cash cow,” Ryugo said of Cochlear’s willingness to get involved. And in Gantz’s lab, “we’re all wondering when the hybrid’s going to be released for general use,” he said. When it is, the Iowa physician’s next concern is that other surgeons will understand how to implant the device. “There are certain surgical strategies you need to make the hybrid work,” he emphasized. “You have to know the anatomy, to get the electrode in there without hurting the critical hair cells. This role may be limited to technical surgerons,” he said, “not general ENT [ear, nose, and throat] doctors. And we’ll need to have people practice this a lot in labs.” In a phone interview, Gantz joked that he wished he could use larger surfaces, like pig ears, or even those of elephants, to practice this difficult surgery.
Gantz emphasized other ways in which inserting a hybrid would be unlike surgery for a normal cochlear implant. Mostly, it comes down to the cochleostomy—or opening of the cochlea—which is considered the most important intracochlear surgery moment. “We do things a little differently at that stage than Niparko does, for example” Gantz said, referring to the surgical style of reknown cochlear implant specialist and Hopkins physician, John Niparko. Though Niparko’s surgery involves a longer electrode, it is still the same width as the electrode of the hybrid, “and so he makes a hole in the cochlea, just like we do, that is 5 millimeters in diameter,” Gantz explained. “But during the cochleostomy, I take extra precaution. I’m very careful not to penetrate into the cochlea.” Gantz uses a sharp, diamond burr and small hooks to open up the snail-shaped organ. “Then I slide the electrtode in gently, in a minute or two,” he said. Gantz explained that so far, trials reveal that surgeons who pay attention to these details are doing quite well.
Beyond surgery, Gantz is also concerned that audiologists will understand how to instruct people in adjusting to hearing with the hybrid, once it is firmly implanted. “At Iowa, we’ve been implanting these on a trial basis for seven years, so our audiologists know how to help patients. But we’ve got to think about how to train other people to explain how to use this device effectively because it’s not easy to use.” After receiving the implant, most patients are pretty excited. “They haven’t heard this well in a long time since they have been struggling so long with hearing aids,” Gantz explained, “and all of a sudden they just say, wow! This is great.” But there are a lot of variables that factor into continued success. “Audiologists have to have a lot of experience with the programming.” Gantz mandates that specialists train and remind his patients that their brains will have to adjust to decoding electronically generated sound. Many people require extensive training to reap full benefits, and some describe an echo effect for a few weeks, as if they were hearing from two different places, until they become accustomed to the hybrid. “It’s not like turning on a lightbulb,” Gantz reiterated. “It may take six months to a year for patients’s brains to register what’s going on.”
But the wait and the training are worthwhile. Several trial patients have had the implant for 4 years now, and Gantz reported that even after that period, they are not at a stagnant place in their adjustment, but are continuing to distinguish more and more words. “It’s really retraining the brain, adapting to this thing,” Gantz said. “It’s like a learning new foreign language.” And he continues to have ideas about how to make his hybrids better. Cutting out all the high-frequencies in the hearing aid, so that the implant alone can cover them, is one strategy. “But most audiologists,” he said, “why would they wanna do that?” It appears that for as much success as his hybrids are likely to have, they will likely face opposition, too.
In the end, hybrid implants work precisely because they don’t go the extra mile, or millimeter. Rather they are a “short” version of their full-spectrum ancestors, the original electrode, combined with the familiar hearing aid. They act on a distinct part of the cochlea and they leave the rest alone, and in doing so, they provide a service that neither an implant or hearing aid could render. Most importanlty for Gantz though, he says the patients who have received his hybrids are happy, and they are no longer avoiding social situations for fear they can’t converse.
.MGW.
In a research lab in Iowa, otolaryngologist Bob Gantz is destroying the cochlea. His cochlea-crushing moves aren’t hindering hearing, however, but helping it. That’s because “the ear,” as Gantz explained “is a forgiving organ,” a fact which scientists too worried about ruining its inner microstructure have not previously understood. They fear that snaking electrodes of cochlear implants into the cochlea destroys whatever hair cells still live there, causing complete hearing loss. Gantz, on the other hand, has dared to poke short electrodes into the cochlear space, and he’s shown that he can obliterate its outermost parts without disturbing the function of the hair cells deeper within the ear. This insight has allowed the University of Iowa scientist to develop a promising new cochlear implant, called the hybrid implant, which combines short electrodes with a familiar device—the hearing aid. Gantz’s invention blends the best of bionics with acoustic hearing to benefit a unique population who could not be helped by implant or hearing aid alone: people with high frequency hearing loss.
Hearing loss depends directly upon the health of hair cells in the cochlea. These microscopic cells, housed along the snail-shaped inner ear, pick up vibrations and convert them into electrical impulses that the brain recognizes as sound. Hairs in the deepest part of the cochlea pick up low-frequency sounds, such as music. Hairs at the cochlea’s entrance pick up high-frequency sounds, including speech. People who are profoundly deaf, like those who wear cochlear implants, can hear neither high nor low-frequency sounds on their own because the majority of their hair cells are damaged.
But complete hearing loss, affecting all the hair cells, isn’t the only type. With age-related hearing problems, for example, or with hearing loss suffered by Iraqi soldiers exposed to relentless gun fire and bomb blasts, not all hearing wanes. Rather, these people tend to lose high-frequency hearing first, meaning their inner hair cells are still intact. While most vowels are in the low frequency range, most consonants are high frequency sound bites, and as such, get distorted or lost for such patients. As specific consonants disappear, individuals can no longer discriminate a “g” from a “t,” for example. And since consonants are the milestones of speech, breaking up words which would otherwise be streams of squishy vowels, people with high-frequency hearing loss have great difficulty with speech understanding. They lose more and more words, until they’re unable to make sense of entire sentences.
For this group, whose only problem is detecting high-frequency sounds, a regular implant is a problem. Its far-reaching electrodes destroy hair cells deep within the ear, eliminating any ability to hear low-frequency information naturally. And even though the implant does step in and provide low-frequency hearing, it is a shackle compared to the cochlea, which, lined with thousands of hair cells, does a far better job of allowing people to hear low-frequency tidbits like music or the pitches in voice that distinguish one speaker from another. Thus, preservation of normal hearing is often preferable to the rougher sound estimates of a surgical implant for patients with residual heairng. But so far, there’s been no way to address patients in this middle ground—to allow them to enjoy the richness of sound through the low cochlear zones that are still working, while compensating for the high-frequency dead zones. These people have had to trudge through life not with implants but with hearing aids, which don’t clarify sound, but simply amplify it. And hearing aids turn up the volume for all sounds, not just speech. “But you could use the hearing aid to make the sound as loud as you like,” Gantz explained “and if you filter those consonants out, the sound still doesn’t make sense as words.” This has made for a disgruntled population of hearing-impaired patients—those who get nervous and depressed at social funtions because they cannot make out words, especially amidst heavy background noise.
Now, Gantz has the solution: make the electrode shorter, so it substitutes only for the hearing that’s already lost. Pair the short implant with a regular hearing aid to amplify the remaining low-frequency hearing, and people with high-frequency hearing loss just might hear again more like they did years earlier.
This resolution seems simple. But the idea to use shorter electrodes to selectively help hearing would certainly not have evolved so soon had Gantz not been willing to take a chance. “Electrodes were seen as risky. Once you start pushing them into the first turn in the inner ear,” Gantz explained, “there is a tendency for these wires to ride right into the sensitive scala media (a fluid-filled sack within the cochlea), meaning you disrupt the hairs cells attached to it and lose all residual hearing.” But Gantz believed that with calculated intrusion, hair cells in the depths of the ear would forgive a little interference. His courgae to explore this notion—to pry and poke in the cochlea—was fueled by observations of the work of a man who had dared to do it with cats, continents away in Australia.
At the Bionic Ear Institute in Melbourne, Robert Shepherd had been testing the fortitude of hair cells since the early 90’s. “I came across Shepherd’s work in a literature search,” Gantz said. “Before I knew about it, I had the concept myself that you could damage some hair cells and the rest would be okay, but I knew I was going to have to do animal studies before I could take this to patients.” Gantz found that Shepherd had already done such studies—the first of their kind—in cats. The Australian’s work involved winding electrodes into the ears of hearing kittens, whose hair cells were fully in tact. “I contacted Shepherd,” Gantz said, “and he told me about the kitten study. Basically, where he put the electrodes, the hair cells were a little bit damaged, but when he went deeper into the cochlea, the hair cells were still okay.”
Shepherd’s promising results in animals were a springboard for Gantz’s eventual work in humans. The Iowa physcian used the Australian scientist’s data “to convince the FDA that there was a possibility we could actually do human studies.” Gantz’s efforts were especially important in light of changing candidacy for cochlear implantation. “Hearing specialists were and are continuing to implant not merely the profoundly deaf, but also deaf people with more and more residual hearing,” he said. “But as you implant these patients, you hurt their remaining low frequency hearing—their music perception, or their ability to distinguish voices.”
By targetting only high-frequency hearing then, Gantz was hoping to avoid this. Ideally, his efforts would help not just a select group of patients, like older folks or Iraqi soldiers with specific high-frequency hearing loss, but also cochlear implant candidates who retained some low-frequency hearing and could benefit by keeping it. “Residual ability to hear is often better than what the implant provides,” Gantz emphasized. In everyday life, problems associated with relying on implant-generated low-frequency hearing are manifest at parties, business meetings, large events, anywhere where more than one voice—differentiated by a slight change in a low-frequency pitch—is presented to a patient. “Patients with cochlear implants always complain that they can’t hear speech in noise,” Gantz said. That’s because the implant doesn’t provide them enough pitch options to distinguish one voice from the next. In a crowd of talkers, many voices may resonate at the same pitch, leaving implant users clueless and frustrated. Hopkins neuroscientist David Ryugo also frequently hears this complaint. “People with hearing problems in noisy places get pretty depressed,” he said. “They might just go sit alone at a table somewhere to get away from the noise or to have a one-on-one conversation.” The physician in Gantz wanted to use his shortened electrode to stop this, to help patients who were going to get implants anyway to keep the best of what they had—their residual ability to detect sound. The scientist in Gantz was ready to explore every possible means of cochlear manipulation to make this a reality. “It’s really a balancing act,” he said, “of where the implant is better versus trying to save the residual hearing.”
In the late 90’s, Gantz began experimenting with act of balancing. He tested with a short electrode which extended only 6millimeters into the cochlea, compared to the standard 24. Gantz’s first test group was a population of subjects with little residual hearing. “I think the 1st group of 6mm subjects had only 10-15% word understanding,” he recalled. By doing trials in these patients, whose hearing abilities were nearly as bad as the profoundly deaf who regularly received full-spectrum implants, Gantz reduced risk. If he were to destroy their residual hearing, they hadn’t started with much anyway. Furthermore, in case his patients did lose this low-frequency ability, which would require them to receive full-spectrum implants, Gantz’s team had prepared a special secondary back-up electrode that could be inserted at the standard distance of 24mm into the ear, right beside the shortened version. His bases were covered.
But Gantz didn’t have to use the back-up. His study was a success. “The most important thing that we learned using the 6mm device,” Gantz said excitedly, “was that we could keep the hair cells of the inner ear alive when we used a short electrode! We knew because we preserved our patients’ voice discrimination just the way it had been for them before their operation.” This was the first time that hair cell plasticity had been demonstrated in humans. “Unfortunately,” Gantz explained, “we did not publish our results since we were trying to get enough data to submit to a high impact journal like Science or Nature. Both publications thought this study was too focused and needed to go to a journal with a speciality.” So Gantz’s work did not see print until 2003. He did present the concept, however, at the 10th anniversary of the National Institute of Deafness in October of 1998.
So far, about 60 patients have received the hybrid implant, manufactured by Cochlear Corporation. About 10 have had it for more than a year. “The device is still in clinical trials but initial results have wowed us,” Gantz said. He’s referring to patients’ ability to understand words. “We have a special test for word understanding,” Gantz explained. “And it’s the most difficult test we can do. We test with words that are monosyllabic.” Gantz explained that when you hear a word in the context of a sentence, “you get a lot of info from the context and you could guess at the words you don’t hear.” But when you hear a monosyllabic word alone, not only is there no emphasis on one syallable or the other, but there’s no context. A patient who can understand such words demonstrates that the hybrid is truly clarifying consonants. And it appears that it is: a year after the surgery, hybrid implant recipients are understanding an average of 70 percent of the words in standard hearing tests—up from 25 percent before the operation when they may have relied soley on hearing aids.
And the combination of bionic and acoustic not only beats a hearing aid, but a regular implant, too, which permits patients to understand just 50% of the words thrown at them in a hearing test. Gantz said that it will be important for some full-spectrum implant wearers to make the transition to hybrids. “Right now,” Gantz said, “a lot of people with 10-15% residual hearing are getting regular implants. They’re going to lose significant low-frequency hearing that way.”
While hybrid implants have proven successful in trials, they’ve not yet been approved by the FDA. Meanwhile, Gantz continues to receive funding from Cochlear Corporation. The Australia-based implant manufacturer waits in the wings for Gantz’s device to be market-ready. “The hybrid implant is a potential cash cow,” Ryugo said of Cochlear’s willingness to get involved. And in Gantz’s lab, “we’re all wondering when the hybrid’s going to be released for general use,” he said. When it is, the Iowa physician’s next concern is that other surgeons will understand how to implant the device. “There are certain surgical strategies you need to make the hybrid work,” he emphasized. “You have to know the anatomy, to get the electrode in there without hurting the critical hair cells. This role may be limited to technical surgerons,” he said, “not general ENT [ear, nose, and throat] doctors. And we’ll need to have people practice this a lot in labs.” In a phone interview, Gantz joked that he wished he could use larger surfaces, like pig ears, or even those of elephants, to practice this difficult surgery.
Gantz emphasized other ways in which inserting a hybrid would be unlike surgery for a normal cochlear implant. Mostly, it comes down to the cochleostomy—or opening of the cochlea—which is considered the most important intracochlear surgery moment. “We do things a little differently at that stage than Niparko does, for example” Gantz said, referring to the surgical style of reknown cochlear implant specialist and Hopkins physician, John Niparko. Though Niparko’s surgery involves a longer electrode, it is still the same width as the electrode of the hybrid, “and so he makes a hole in the cochlea, just like we do, that is 5 millimeters in diameter,” Gantz explained. “But during the cochleostomy, I take extra precaution. I’m very careful not to penetrate into the cochlea.” Gantz uses a sharp, diamond burr and small hooks to open up the snail-shaped organ. “Then I slide the electrtode in gently, in a minute or two,” he said. Gantz explained that so far, trials reveal that surgeons who pay attention to these details are doing quite well.
Beyond surgery, Gantz is also concerned that audiologists will understand how to instruct people in adjusting to hearing with the hybrid, once it is firmly implanted. “At Iowa, we’ve been implanting these on a trial basis for seven years, so our audiologists know how to help patients. But we’ve got to think about how to train other people to explain how to use this device effectively because it’s not easy to use.” After receiving the implant, most patients are pretty excited. “They haven’t heard this well in a long time since they have been struggling so long with hearing aids,” Gantz explained, “and all of a sudden they just say, wow! This is great.” But there are a lot of variables that factor into continued success. “Audiologists have to have a lot of experience with the programming.” Gantz mandates that specialists train and remind his patients that their brains will have to adjust to decoding electronically generated sound. Many people require extensive training to reap full benefits, and some describe an echo effect for a few weeks, as if they were hearing from two different places, until they become accustomed to the hybrid. “It’s not like turning on a lightbulb,” Gantz reiterated. “It may take six months to a year for patients’s brains to register what’s going on.”
But the wait and the training are worthwhile. Several trial patients have had the implant for 4 years now, and Gantz reported that even after that period, they are not at a stagnant place in their adjustment, but are continuing to distinguish more and more words. “It’s really retraining the brain, adapting to this thing,” Gantz said. “It’s like a learning new foreign language.” And he continues to have ideas about how to make his hybrids better. Cutting out all the high-frequencies in the hearing aid, so that the implant alone can cover them, is one strategy. “But most audiologists,” he said, “why would they wanna do that?” It appears that for as much success as his hybrids are likely to have, they will likely face opposition, too.
In the end, hybrid implants work precisely because they don’t go the extra mile, or millimeter. Rather they are a “short” version of their full-spectrum ancestors, the original electrode, combined with the familiar hearing aid. They act on a distinct part of the cochlea and they leave the rest alone, and in doing so, they provide a service that neither an implant or hearing aid could render. Most importanlty for Gantz though, he says the patients who have received his hybrids are happy, and they are no longer avoiding social situations for fear they can’t converse.
.MGW.
posted by Meagan G at
9:19 AM
<< Home