Interview with William F. House M.D., President and Founder, AllHear, Inc.
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AO/Beck: Dr. House it is an honor to speak with you. You have been responsible for the vision and the development of cochlear implants, modern surgical approaches to acoustic neuromas and a plethora of surgical instruments. In fact, your list of accomplishments is literally too long to mention here. Your contributions 'so all may hear' have been staggering.
House: Thanks Doug, it's nice to spend some time with you again - it's been quite a while since we last spoke.
AO/Beck: In the mid-1980s, I had the pleasure of working for you in the office, the lab and the operating room at the House Ear Institute (HEI). At that time, there were many new and exciting things going on in otology and audiology. HEI had just secured FDA approval for the cochlear implant and was working on new CI processors and sound processing strategies. The brain-stem implant was already on the drawing board at HEI and a year or two later the first brain-stem implant was done. Additionally, audiologists, otologists and engineers at HEI were working on the Hoover Digital Hearing Aid Project and they were recording digitized speech samples to develop tests to measure hearing aid benefits --17 years ago!
So using that as a brief introduction, let's start with acoustic neuromas. Would you please give me a brief overview of acoustic neuroma surgery?
House: When I started clinical practice, I got interested in acoustic neuromas (ANs) because they were a devastating problem for the patients and the surgeons. The difficulty was that surgical treatment for acoustic neuroma at that time, resulted in 100 percent loss of the facial nerve, and a very high mortality rate. In fact, I recall that in California, the mortality rate was 40 percent. So, even though we could diagnose these tumors, they were rarely operated until very late stages and as you know, that made them even more difficult to remove. So the high mortality and the morbidity of the facial nerve became more acceptable when weighed against the operation saving the patient's life. But, there was increasing evidence that if we could remove the tumor when they were smaller, and if we could save the facial nerve, the results would be far more acceptable. This was a goal I believed in and decided to work on. I had started working with the operating microscope and this was an important development which had just come out when I started my practice in 1956. I thought that if we could apply the operating microscope to neurotologic surgery, we could get better results. The microscope allowed us to see the blood vessels which are vital to the brainstem, as well as the tumor and of course the anatomy with much greater detail. Basically, the operating microscope allowed us to avoid damaging vital structures. The operating microscope was critically important in allowing us to approach the tumors through the temporal bone. The reality was that these patients were all going to have a deaf ear anyway, so if we could develop a surgical technique which brought us through the ear, which was anatomy we knew very well, it could be useful to remove the tumors, while saving the facial nerve and reducing morbidity and mortality. In those days (through the 1950s and 1960s) the approach to acoustics was almost always via the suboccipital approach, which goes through the back of the head and required retracting the cerebellum, or actually removing a piece of the cerebellum to gain access. Of course, just retracting the cerebellum can cause morbidity. So, I began to work on the translabyrinthine approach (TLC) to acoustic neuromas with different neurosurgeons, some were cooperative and some were not. This was a highly controversial surgical approach at that time. I worked out a cooperative relationship with Dr. Bill Hitselberger and the two of us began to work on the concepts of how to approach theses tumors with minimal retracting of the brain and at the same time with complete visibility using the operating microscope. We developed methods of identifying the facial nerve as it enters the temporal bone and in that way we could carefully dissect the nerve away from the tumor. This led us to some positive results and we started to have patients who didn't have facial paralysis post-op. Over time, the techniques and the tools improved tremendously and the original mortality of some ten percent had been reduced to about one half of one percent and the facial nerve is now being saved in more than 90 percent of the reported cases and in many cases the hearing can be saved too. The use of MRI to help diagnose these tumors when they are very small has also been a great benefit to further reduce the morbidity and mortality for these patients. The surgical results have been dramatically improved over these past 45 years.
AO/Beck: When I was at HEI, it was not unusual for there to be two, and on some occasion three acoustics scheduled for one day. My recollection from HEI was that from 'skin-to-skin' most ANs were removed in about 3 to 4 hours, is that correct? And, for historical purposes, can you tell me how many acoustics have you removed?
House: For most of us in the group, three to four hours was typical. Some went longer and some were quicker. I'd guess that I've removed about 2000 or so. Dr. Hitselberger has removed more than that and he's still doing them with the group in Los Angeles.
AO/Beck: What are your thoughts on Gamma Knife (radiation therapy) for ANs?
House: I think it has a place but there is still a lot of controversy with Gamma Knife. Studies of Gamma Knife treatment have not yet reported long term results. The tumors are not always completely managed and some of the tumors do recur. Of course one big advantage of Gamma Knife is the patients are usually in the hospital only one day. I don't think Gamma Knife will ever completely replace surgical removal of ANs. In many cases the results of surgical removal are quite good and well documented. So in essence, I think the jury is still out but I'd personally like to see more long-term studies on Gamma Knife outcomes.
AO/Beck: Dr. House, let's switch gears to intraoperative monitoring. For many years, otologists have monitored the facial nerve. In the early days, some surgeons had the scrub nurse place her hand on the patient's face to feel and report to the surgeon contractions and twitches during surgery. I recall a paper written by an otologist who had sutured 'jingle bells' onto the patient's face, then when he stimulated the facial nerve during surgery, the bells would jiggle and make noise. However, these gross observations and subjective reports were not as accurate or repeatable as one might desire. Dr. Weldon Selters and others has worked with you in the operating room in the 1970s to develop electrophysiologically based facial nerve intraoperative monitoring (IOM) to monitor the EMG response from the facial nerve. In brief, the idea was that when the facial nerve was stimulated during surgery, there would be a motoric (EMG) response within the facial musculature and if the response from those muscles could be acoustically broadcast into the OR at the same instant the surgeon touched the nerve. In essence, the surgeon would instantly hear the response of the musculature. In that way, the EMG response served as an early warning system and as a verification of facial nerve integrity. How did IOM impact your surgical technique?
House: Well, IOM has become the standard of care for these cases. IOM allows us to more quickly and accurately remove the tumors because we can tell exactly where the facial nerve is and if it's at immediate risk for injury. Facial nerve IOM has undergone great advances and it's helped improve the results of acoustic neuroma surgery.
AO/Beck: With that said, tell me a little about your observations on eighth nerve IOM? Has that been as useful as seventh nerve monitoring?
House: Most of the time no. It is useful in some respects but it's often too slow. By the time IOM ABR had noted a change it was after the fact and there was little we could do to change the outcome. On the other hand some of the direct nerve and ECochG IOM monitoring are still being developed and may prove to be highly valuable in the future.
AO/Beck: We could spend the whole day talking about acoustics and IOM, but I think I'd better move on to the area you're probably best known for, at least to the majority of audiologists around the world. Of course I'm referring to the development of the cochlear implant. When I got to HEI, the FDA had just approved the implant for adults, and you were finishing clinical trials with children. The rumor at that time was that you had waived the surgical fees for the kids who needed implants but were unable to pay for them - was that true?
House: Yes, well most of them we didn't charge for the surgery back then. We were interested in getting children implanted and the surgical fees had little to do with that. So if we could get the hospital and the anesthesia costs taken care of, many times we didn't charge for the surgery. That gave us the opportunity to study more cases. Jack Urban never charged for the original engineering work either. We basically did the work on a shoestring because the emphasis was on the results. We believed we could help children hear and it we kept that as the primary goal.
AO/Beck: What year was the first cochlear implant?
House: I did my first implant in 1956. That was a very basic device and we did two cases. Unfortunately, the devices weren't very good with respect to biocompatibility and the patients got inflammatory reactions around the implant. Frankly, that scared me and I took the devices out. But during the week or two they were functioning, I was very impressed that totally deaf patients had a sensation of hearing. It was clear to me this was the way to go. We didn't really get good biocompatible materials until the late 60s and early 70s and that's when the whole thing started to take off.
AO/Beck: What was is that you implanted in 1956?
House: The earliest implants I used had 5 or 6 electrodes. We had a little button through which we could measure the current. It was simple and somewhat crude by today's standards, but it worked.
AO/Beck: OK, well let's fast forward to the mid-1980s, when the FDA approved the first cochlear implant in adults. That device was a single electrode, single channel device.
House: Yes, and then about two or three years later the FDA approved the device in children. We felt that we needed to study the results in adults and then we hoped we could extrapolate a bit of that data for applications in children.
AO/Beck: Currently, there are two or three multichannel, multielectrode devices on the market. I understand that you're now working to obtain FDA approval on a new single channel product called the 'AllHear'. What can you tell me about that?
House: Yes, the AllHear is based on the old 3M device. We haven't changed the implanted device very much from that original design. The 3M device had a capacitor inside to eliminate/reduce the chance of DC current. By using a capacitor and two platinum electrodes in the AllHear, we avoid the DC current problem. The active electrode goes into the cochlea 6 mm and the return is in the temporalis muscle.
AO/Beck: Is the AllHear an ear level or a body worn device?
House: It's available as an ear level device. It's a little bigger than a post-auricular BTE. It's a very simple device with a class D circuit and compression. We've extended the high frequency range beyond the old 'telephone frequencies' of the Sigma and the Alpha devices. When Jack Urban and I started designing the early units we decided to limit the spectral response of the implant to the narrowest band possible as we were concerned that too much electrical stimulation might further damage the inner ear or the auditory nerve. We limited the response at that time from about 250 to about 2700 Hz.
As you know, frequencies above 2700 Hz have significant impact on word recognition.
AO/Beck: What is the spectral response of the AllHear?
House: It runs from about 200 to about 8000 Hz.
AO/Beck: Can you tell me about how many people have been implanted with the new AllHear?
House: The worldwide total (including some retrofits of the old 3M) is about 200 people.
AO/Beck: So the AllHear is not FDA approved?
House: Not yet. At this time it's an investigational device for adults. Overseas, some of the implant centers are implanting it in the full range of adult and children patients.
AO/Beck: In my reading of the literature, it seemed like one of the target populations for the AllHear instrument were patients who had ossified cochleas due to meningitis (i.e., 'drill-outs'), is that correct?
House: Yes, since the electrode is only intended to go into the cochlea some 6 mm, it's much easier to get a full insertion on ossified cochleas.
AO/Beck: What can you tell me about the results of the multi-channel, multi-electrode digital devices, compared to the outcomes of the AllHear?
House: Back in the early days, Jack Urban and I found that we got better results by using return electrodes outside of the cochlea. Additionally, we found that by using the electrode outside the cochlea, it required less total electrical energy to get an auditory response. Anyway, this was heavily criticized at the time because the multi-channel devices tried to limit the spread of current across the dendrites. But later it was found that the dendrites were actually absent, according to the Linthicum study, and so then the only place of stimulation was the spiral ganglion cells. When multi-channel digital circuitry arrived, the power requirement was so great that the battery life was only 7 or 8 hours. Then it was re-discovered that by placing the return electrode outside the cochlea, in the temporalis muscle, power consumption was decreased and battery life was increased. In Germany, there was a study which compared speech discrimination with bipolar systems (meaning from active to ground electrodes inside the cochlea), as compared to the monopolar system (meaning from an intracochlear active electrode to a return electrode outside of the cochlea) and it became apparent that trying to obtain tonotopic stimulation or by trying to follow the traveling wave to stimulate at a specific location along the cochlea to obtain a specific frequency response was unnecessary. The results showed that the patients got about the same results with the bipolar and the monopolar stimulation systems. At this time, most of the devices use a return electrode outside the cochlea. So basically, we need to develop new theories to explain how cochlear implants work. The theory I buy into currently includes the assumption that the spiral ganglion cells and eighth nerve fibers are tuned to specific frequencies and intensities, and will only respond to certain intensities and frequencies. The nerve fibers themselves pick out what frequencies and intensities they are going to transmit. That is, it may have less to do with the information we provide the cochlea, and more to do with what the cochlea has to transmit.
AO/Beck: What can you tell me specifically about the outcomes of patients with respect to speech understanding with the AllHear compared to the digital multi-channel, multi-electrode devices?
House: They all did well with open-set speech discrimination and we have a number of patients with the AllHear who can use the phone proficiently.
AO/Beck: It really causes one to pause when you report patients with the AllHear device can actually be compared favorably to patients with extremely high tech devices. How do you explain that?
House: Technology is wonderful. We all benefit from higher technology in our homes, our offices and in our lives. But higher technology doesn't always mean better results. That is, we know that digital technology has enabled us to do far more than we would have thought possible just ten years ago. But it's not better just because it's digital. The theory sounds great, but with cochlear implants you have to remember that in the early days most people thought implants would never work at all. The NIH setup a study in 1970 or so of my first eleven patients and they decided that although implants worked, they recommended multi-channel devices. Their recommendation was entirely based on theory. Our approach was based on clinical results. It's important to remember that we started with multi-electrode devices and went to single channel devices because the clinical results led us that way. Now, all that theory has resulted in thousands of patients being implanted with very sophisticated, multi-electrode devices and there are lots of commercial interests involved too. These things are hard to overcome and they impact the state of the art. That's really where the controversy started. The debate between single and multiple electrodes has never been purely based on clinical outcomes. Additionally, I feel very strongly that cochlear implants can and should be made much more practical and much more economical. I believe we need to accomplish this to make implants available to all of those people who need them. The cost of the AllHear is about one-third the cost of the multi-channel, multi-electrode units. Additionally, we can set the audiologic controls with a few trimpots, similar to some programmable hearing aids. The AllHear unit is practical and can be adjusted in the audiologists' office. I can envision a time when patients with an 80 dB or worse hearing loss, who are not doing well with hearing aids, would be referred by the audiologist to a surgical center for implantation. Following the implant, the patient would be sent back to the audiologist for the tune-up and maintenance issues related to the implant, just as they are now followed by the audiologist for their hearing aids.
AO/Beck: That sounds like a marvelous model for the surgeon, the audiologist and the patient. However, one big issue for audiologists when we take on the responsibility of the patient is that audiologists have an extremely hard time getting reimbursed for professional fees relating to hearing aid services, cochlear implant services and particularly rehabilitation, central auditory processing and counseling are very hard to get paid for. How do we get past that?
House: I can envision a model where the referring audiologist is actually paid by the surgeon or the surgical center for preimplant and rehabilitative services. That is, the fee to the insurance company, or whomever is paying for the implant would be a bundled fee including all products and services. Then the surgeon or the surgical center would contract with the audiologist for the specific pre-implant and follow-up services. My concept is that we can present a whole package to an HMO whereby the total cost for the evaluation, the implant, the surgical fees, post-operative care and audiologic services can be around sixteen thousand dollars. That's about one-third of the average
price for implantation today. I think this model is practical and can help make implants more available for those who need them.
AO/Beck: Dr. House, for audiologists and patients who want to learn more about the AllHear, how do they contact you?
House: Although we're happy to help inform people about what we're doing, and what our thoughts are, please remember that we're in FDA clinical trials. After we get FDA approval and pre-market approval (PMA) then we expect it'll move forward quickly.
However, they can certainly find information on our webpage www.allhear.com in the meantime, or they can send us email to William_House@AllHear.com.
AO/Beck: Dr. House, as always it's a pleasure to spend time with you and get your thoughts on these issues. I appreciate your time and insight and I'll look forward to following up with you in the near future.
House: Thanks Doug, I wish you and Audiology Online all the best.
House: Thanks Doug, it's nice to spend some time with you again - it's been quite a while since we last spoke.
AO/Beck: In the mid-1980s, I had the pleasure of working for you in the office, the lab and the operating room at the House Ear Institute (HEI). At that time, there were many new and exciting things going on in otology and audiology. HEI had just secured FDA approval for the cochlear implant and was working on new CI processors and sound processing strategies. The brain-stem implant was already on the drawing board at HEI and a year or two later the first brain-stem implant was done. Additionally, audiologists, otologists and engineers at HEI were working on the Hoover Digital Hearing Aid Project and they were recording digitized speech samples to develop tests to measure hearing aid benefits --17 years ago!
So using that as a brief introduction, let's start with acoustic neuromas. Would you please give me a brief overview of acoustic neuroma surgery?
House: When I started clinical practice, I got interested in acoustic neuromas (ANs) because they were a devastating problem for the patients and the surgeons. The difficulty was that surgical treatment for acoustic neuroma at that time, resulted in 100 percent loss of the facial nerve, and a very high mortality rate. In fact, I recall that in California, the mortality rate was 40 percent. So, even though we could diagnose these tumors, they were rarely operated until very late stages and as you know, that made them even more difficult to remove. So the high mortality and the morbidity of the facial nerve became more acceptable when weighed against the operation saving the patient's life. But, there was increasing evidence that if we could remove the tumor when they were smaller, and if we could save the facial nerve, the results would be far more acceptable. This was a goal I believed in and decided to work on. I had started working with the operating microscope and this was an important development which had just come out when I started my practice in 1956. I thought that if we could apply the operating microscope to neurotologic surgery, we could get better results. The microscope allowed us to see the blood vessels which are vital to the brainstem, as well as the tumor and of course the anatomy with much greater detail. Basically, the operating microscope allowed us to avoid damaging vital structures. The operating microscope was critically important in allowing us to approach the tumors through the temporal bone. The reality was that these patients were all going to have a deaf ear anyway, so if we could develop a surgical technique which brought us through the ear, which was anatomy we knew very well, it could be useful to remove the tumors, while saving the facial nerve and reducing morbidity and mortality. In those days (through the 1950s and 1960s) the approach to acoustics was almost always via the suboccipital approach, which goes through the back of the head and required retracting the cerebellum, or actually removing a piece of the cerebellum to gain access. Of course, just retracting the cerebellum can cause morbidity. So, I began to work on the translabyrinthine approach (TLC) to acoustic neuromas with different neurosurgeons, some were cooperative and some were not. This was a highly controversial surgical approach at that time. I worked out a cooperative relationship with Dr. Bill Hitselberger and the two of us began to work on the concepts of how to approach theses tumors with minimal retracting of the brain and at the same time with complete visibility using the operating microscope. We developed methods of identifying the facial nerve as it enters the temporal bone and in that way we could carefully dissect the nerve away from the tumor. This led us to some positive results and we started to have patients who didn't have facial paralysis post-op. Over time, the techniques and the tools improved tremendously and the original mortality of some ten percent had been reduced to about one half of one percent and the facial nerve is now being saved in more than 90 percent of the reported cases and in many cases the hearing can be saved too. The use of MRI to help diagnose these tumors when they are very small has also been a great benefit to further reduce the morbidity and mortality for these patients. The surgical results have been dramatically improved over these past 45 years.
AO/Beck: When I was at HEI, it was not unusual for there to be two, and on some occasion three acoustics scheduled for one day. My recollection from HEI was that from 'skin-to-skin' most ANs were removed in about 3 to 4 hours, is that correct? And, for historical purposes, can you tell me how many acoustics have you removed?
House: For most of us in the group, three to four hours was typical. Some went longer and some were quicker. I'd guess that I've removed about 2000 or so. Dr. Hitselberger has removed more than that and he's still doing them with the group in Los Angeles.
AO/Beck: What are your thoughts on Gamma Knife (radiation therapy) for ANs?
House: I think it has a place but there is still a lot of controversy with Gamma Knife. Studies of Gamma Knife treatment have not yet reported long term results. The tumors are not always completely managed and some of the tumors do recur. Of course one big advantage of Gamma Knife is the patients are usually in the hospital only one day. I don't think Gamma Knife will ever completely replace surgical removal of ANs. In many cases the results of surgical removal are quite good and well documented. So in essence, I think the jury is still out but I'd personally like to see more long-term studies on Gamma Knife outcomes.
AO/Beck: Dr. House, let's switch gears to intraoperative monitoring. For many years, otologists have monitored the facial nerve. In the early days, some surgeons had the scrub nurse place her hand on the patient's face to feel and report to the surgeon contractions and twitches during surgery. I recall a paper written by an otologist who had sutured 'jingle bells' onto the patient's face, then when he stimulated the facial nerve during surgery, the bells would jiggle and make noise. However, these gross observations and subjective reports were not as accurate or repeatable as one might desire. Dr. Weldon Selters and others has worked with you in the operating room in the 1970s to develop electrophysiologically based facial nerve intraoperative monitoring (IOM) to monitor the EMG response from the facial nerve. In brief, the idea was that when the facial nerve was stimulated during surgery, there would be a motoric (EMG) response within the facial musculature and if the response from those muscles could be acoustically broadcast into the OR at the same instant the surgeon touched the nerve. In essence, the surgeon would instantly hear the response of the musculature. In that way, the EMG response served as an early warning system and as a verification of facial nerve integrity. How did IOM impact your surgical technique?
House: Well, IOM has become the standard of care for these cases. IOM allows us to more quickly and accurately remove the tumors because we can tell exactly where the facial nerve is and if it's at immediate risk for injury. Facial nerve IOM has undergone great advances and it's helped improve the results of acoustic neuroma surgery.
AO/Beck: With that said, tell me a little about your observations on eighth nerve IOM? Has that been as useful as seventh nerve monitoring?
House: Most of the time no. It is useful in some respects but it's often too slow. By the time IOM ABR had noted a change it was after the fact and there was little we could do to change the outcome. On the other hand some of the direct nerve and ECochG IOM monitoring are still being developed and may prove to be highly valuable in the future.
AO/Beck: We could spend the whole day talking about acoustics and IOM, but I think I'd better move on to the area you're probably best known for, at least to the majority of audiologists around the world. Of course I'm referring to the development of the cochlear implant. When I got to HEI, the FDA had just approved the implant for adults, and you were finishing clinical trials with children. The rumor at that time was that you had waived the surgical fees for the kids who needed implants but were unable to pay for them - was that true?
House: Yes, well most of them we didn't charge for the surgery back then. We were interested in getting children implanted and the surgical fees had little to do with that. So if we could get the hospital and the anesthesia costs taken care of, many times we didn't charge for the surgery. That gave us the opportunity to study more cases. Jack Urban never charged for the original engineering work either. We basically did the work on a shoestring because the emphasis was on the results. We believed we could help children hear and it we kept that as the primary goal.
AO/Beck: What year was the first cochlear implant?
House: I did my first implant in 1956. That was a very basic device and we did two cases. Unfortunately, the devices weren't very good with respect to biocompatibility and the patients got inflammatory reactions around the implant. Frankly, that scared me and I took the devices out. But during the week or two they were functioning, I was very impressed that totally deaf patients had a sensation of hearing. It was clear to me this was the way to go. We didn't really get good biocompatible materials until the late 60s and early 70s and that's when the whole thing started to take off.
AO/Beck: What was is that you implanted in 1956?
House: The earliest implants I used had 5 or 6 electrodes. We had a little button through which we could measure the current. It was simple and somewhat crude by today's standards, but it worked.
AO/Beck: OK, well let's fast forward to the mid-1980s, when the FDA approved the first cochlear implant in adults. That device was a single electrode, single channel device.
House: Yes, and then about two or three years later the FDA approved the device in children. We felt that we needed to study the results in adults and then we hoped we could extrapolate a bit of that data for applications in children.
AO/Beck: Currently, there are two or three multichannel, multielectrode devices on the market. I understand that you're now working to obtain FDA approval on a new single channel product called the 'AllHear'. What can you tell me about that?
House: Yes, the AllHear is based on the old 3M device. We haven't changed the implanted device very much from that original design. The 3M device had a capacitor inside to eliminate/reduce the chance of DC current. By using a capacitor and two platinum electrodes in the AllHear, we avoid the DC current problem. The active electrode goes into the cochlea 6 mm and the return is in the temporalis muscle.
AO/Beck: Is the AllHear an ear level or a body worn device?
House: It's available as an ear level device. It's a little bigger than a post-auricular BTE. It's a very simple device with a class D circuit and compression. We've extended the high frequency range beyond the old 'telephone frequencies' of the Sigma and the Alpha devices. When Jack Urban and I started designing the early units we decided to limit the spectral response of the implant to the narrowest band possible as we were concerned that too much electrical stimulation might further damage the inner ear or the auditory nerve. We limited the response at that time from about 250 to about 2700 Hz.
As you know, frequencies above 2700 Hz have significant impact on word recognition.
AO/Beck: What is the spectral response of the AllHear?
House: It runs from about 200 to about 8000 Hz.
AO/Beck: Can you tell me about how many people have been implanted with the new AllHear?
House: The worldwide total (including some retrofits of the old 3M) is about 200 people.
AO/Beck: So the AllHear is not FDA approved?
House: Not yet. At this time it's an investigational device for adults. Overseas, some of the implant centers are implanting it in the full range of adult and children patients.
AO/Beck: In my reading of the literature, it seemed like one of the target populations for the AllHear instrument were patients who had ossified cochleas due to meningitis (i.e., 'drill-outs'), is that correct?
House: Yes, since the electrode is only intended to go into the cochlea some 6 mm, it's much easier to get a full insertion on ossified cochleas.
AO/Beck: What can you tell me about the results of the multi-channel, multi-electrode digital devices, compared to the outcomes of the AllHear?
House: Back in the early days, Jack Urban and I found that we got better results by using return electrodes outside of the cochlea. Additionally, we found that by using the electrode outside the cochlea, it required less total electrical energy to get an auditory response. Anyway, this was heavily criticized at the time because the multi-channel devices tried to limit the spread of current across the dendrites. But later it was found that the dendrites were actually absent, according to the Linthicum study, and so then the only place of stimulation was the spiral ganglion cells. When multi-channel digital circuitry arrived, the power requirement was so great that the battery life was only 7 or 8 hours. Then it was re-discovered that by placing the return electrode outside the cochlea, in the temporalis muscle, power consumption was decreased and battery life was increased. In Germany, there was a study which compared speech discrimination with bipolar systems (meaning from active to ground electrodes inside the cochlea), as compared to the monopolar system (meaning from an intracochlear active electrode to a return electrode outside of the cochlea) and it became apparent that trying to obtain tonotopic stimulation or by trying to follow the traveling wave to stimulate at a specific location along the cochlea to obtain a specific frequency response was unnecessary. The results showed that the patients got about the same results with the bipolar and the monopolar stimulation systems. At this time, most of the devices use a return electrode outside the cochlea. So basically, we need to develop new theories to explain how cochlear implants work. The theory I buy into currently includes the assumption that the spiral ganglion cells and eighth nerve fibers are tuned to specific frequencies and intensities, and will only respond to certain intensities and frequencies. The nerve fibers themselves pick out what frequencies and intensities they are going to transmit. That is, it may have less to do with the information we provide the cochlea, and more to do with what the cochlea has to transmit.
AO/Beck: What can you tell me specifically about the outcomes of patients with respect to speech understanding with the AllHear compared to the digital multi-channel, multi-electrode devices?
House: They all did well with open-set speech discrimination and we have a number of patients with the AllHear who can use the phone proficiently.
AO/Beck: It really causes one to pause when you report patients with the AllHear device can actually be compared favorably to patients with extremely high tech devices. How do you explain that?
House: Technology is wonderful. We all benefit from higher technology in our homes, our offices and in our lives. But higher technology doesn't always mean better results. That is, we know that digital technology has enabled us to do far more than we would have thought possible just ten years ago. But it's not better just because it's digital. The theory sounds great, but with cochlear implants you have to remember that in the early days most people thought implants would never work at all. The NIH setup a study in 1970 or so of my first eleven patients and they decided that although implants worked, they recommended multi-channel devices. Their recommendation was entirely based on theory. Our approach was based on clinical results. It's important to remember that we started with multi-electrode devices and went to single channel devices because the clinical results led us that way. Now, all that theory has resulted in thousands of patients being implanted with very sophisticated, multi-electrode devices and there are lots of commercial interests involved too. These things are hard to overcome and they impact the state of the art. That's really where the controversy started. The debate between single and multiple electrodes has never been purely based on clinical outcomes. Additionally, I feel very strongly that cochlear implants can and should be made much more practical and much more economical. I believe we need to accomplish this to make implants available to all of those people who need them. The cost of the AllHear is about one-third the cost of the multi-channel, multi-electrode units. Additionally, we can set the audiologic controls with a few trimpots, similar to some programmable hearing aids. The AllHear unit is practical and can be adjusted in the audiologists' office. I can envision a time when patients with an 80 dB or worse hearing loss, who are not doing well with hearing aids, would be referred by the audiologist to a surgical center for implantation. Following the implant, the patient would be sent back to the audiologist for the tune-up and maintenance issues related to the implant, just as they are now followed by the audiologist for their hearing aids.
AO/Beck: That sounds like a marvelous model for the surgeon, the audiologist and the patient. However, one big issue for audiologists when we take on the responsibility of the patient is that audiologists have an extremely hard time getting reimbursed for professional fees relating to hearing aid services, cochlear implant services and particularly rehabilitation, central auditory processing and counseling are very hard to get paid for. How do we get past that?
House: I can envision a model where the referring audiologist is actually paid by the surgeon or the surgical center for preimplant and rehabilitative services. That is, the fee to the insurance company, or whomever is paying for the implant would be a bundled fee including all products and services. Then the surgeon or the surgical center would contract with the audiologist for the specific pre-implant and follow-up services. My concept is that we can present a whole package to an HMO whereby the total cost for the evaluation, the implant, the surgical fees, post-operative care and audiologic services can be around sixteen thousand dollars. That's about one-third of the average
price for implantation today. I think this model is practical and can help make implants more available for those who need them.
AO/Beck: Dr. House, for audiologists and patients who want to learn more about the AllHear, how do they contact you?
House: Although we're happy to help inform people about what we're doing, and what our thoughts are, please remember that we're in FDA clinical trials. After we get FDA approval and pre-market approval (PMA) then we expect it'll move forward quickly.
However, they can certainly find information on our webpage www.allhear.com in the meantime, or they can send us email to William_House@AllHear.com.
AO/Beck: Dr. House, as always it's a pleasure to spend time with you and get your thoughts on these issues. I appreciate your time and insight and I'll look forward to following up with you in the near future.
House: Thanks Doug, I wish you and Audiology Online all the best.
