This has certain implications for current research into hearing – and cochlear implant research and development.

http://www.sciencedaily.com/releases/2007/10/071011140215.htm

New Hearing Mechanism Discovered

MIT researchers have discovered a hearing mechanism that fundamentally changes the current understanding of inner ear function. This new mechanism could help explain the ear’s remarkable ability to sense and discriminate sounds. Its discovery could eventually lead to improved systems for restoring hearing.

MIT Professor Dennis Freeman, left, graduate student Roozbeh Ghaffari and research scientist Alexander J. Aranyosi have found that the tectorial membrane, a gelatinous structure inside the cochlea of the ear, is much more important to hearing than previously thought.

MIT Professor Dennis M. Freeman, working with graduate student Roozbeh Ghaffari and research scientist Alexander J. Aranyosi, found that the tectorial membrane, a gelatinous structure inside the cochlea of the ear, is much more important to hearing than previously thought. It can selectively pick up and transmit energy to different parts of the cochlea via a kind of wave that is different from that commonly associated with hearing.
Ghaffari, the lead author of the paper, is in the Harvard-MIT Division of Health Sciences and Technology, as is Freeman. All three researchers are in MIT’s Research Laboratory of Electronics. Freeman is also in MIT’s Department of Electrical Engineering and Computer Science and the Massachusetts Eye and Ear Infirmary.

It has been known for over half a century that inside the cochlea sound waves are translated into up-and-down waves that travel along a structure called the basilar membrane. But the team has now found that a different kind of wave, a traveling wave that moves from side to side, can also carry sound energy. This wave moves along the tectorial membrane, which is situated directly above the sensory hair cells that transmit sounds to the brain. This second wave mechanism is poised to play a crucial role in delivering sound signals to these hair cells.

In short, the ear can mechanically translate sounds into two different kinds of wave motion at once. These waves can interact to excite the hair cells and enhance their sensitivity, “which may help explain how we hear sounds as quiet as whispers,” says Aranyosi. The interactions between these two wave mechanisms may be a key part of how we are able to hear with such fidelity – for example, knowing when a single instrument in an orchestra is out of tune.

“We know the ear is enormously sensitive” in its ability to discriminate between different kinds of sound, Freeman says. “We don’t know the mechanism that lets it do that.” The new work has revealed “a whole new mechanism that nobody had thought of. It’s really a very different way of looking at things.”

The tectorial membrane is difficult to study because it is small (the entire length could fit inside a one-inch piece of human hair), fragile (it is 97 percent water, with a consistency similar to that of a jellyfish), and nearly transparent. In addition, sound vibrations cause nanometer-scale displacements of cochlear structures at audio frequencies. “We had to develop an entirely new class of measurement tools for the nano-scale regime,” Ghaffari says.

The team learned about the new wave mechanism by suspending an isolated piece of tectorial membrane between two supports, one fixed and one moveable. They launched waves at audio frequencies along the membrane and watched how it responded by using a stroboscopic imaging system developed in Freeman’s lab. That system can measure nanometer-scale displacements at frequencies up to a million cycles per second.
The team’s discovery has implications for how we model cochlear mechanisms. “In the long run, this could affect the design of hearing aids and cochlear implants,” says Ghaffari. The research also has implications for inherited forms of hearing loss that affect the tectorial membrane. Previous measurements of cochlear function in mouse models of these diseases “are consistent with disruptions of this second wave,” Aranyosi adds.

Because the tectorial membrane is so tiny and so fragile, people “tend to think of it as something that’s wimpy and not important,” Freeman says. “Well, it’s not wimpy at all.” The new discovery “that it can transport energy throughout the cochlea is very significant, and it’s not something that’s intuitive.”

The research is described in the advance online issue of the Proceedings of the National Academy of Sciences the week of October 8.

This research was funded by the National Institutes of Health.

New research at http://www.jneurosci.org/cgi/content/abstract/27/29/7838, paper accessible only by individual or institutional subscription.

Guiraud published a paper in the Journal of Neuroscience, with results indicating that the brain reorganises its auditory pathways, and may even activate out-of-service ones upon sound stimuli, even after years of deafness. Notably, she says, “Altogether, our results strongly suggest that, after at least 3 months of cochlear implant use, the recipient’s auditory cortex presents a tonotopic organization that resembles the frequency maps of normal-hearing subjects.”

In simple terms, after 3 months of cochlear implant use, implantees’ brains look similar to normal-hearing people’s brains, at least, from an auditory perspective.

The study was supported by Advanced Bionics.

From a presentation on ‘Psychophysics – is faster better?” from Cochlear at one of their quarterly talks. This is a summarised and layman’s version (my own interpretation, so there might be errors).

Cochlear was studying how the brain interprets sound. They said that electrode position was more important than the no. of virtual channels offered (an obvious dig at Advanced Bionics, who touts their high no. of virtual channels). The presentation also mentioned that there was a limit to the improvement in performance in increasing the electrical stimulation rate. Apparently, performance plateaus out at 300Hz.

One thing I noted was that some of the studies the presentation included were not statistically valid. For example, they included a study from the American Freedom clinical trial which had about 28 patients – this sample size is too small to draw valid conclusions. However, it must be noted that in perspective, a sample size this large is considered to be very good – it is difficult to find co-operative individuals of similar history and conditions who will participate in a study for a year or a more.

A participant asked a question on tonal languages ie Mandarin Chinese. The presenter said that the speech processors were designed primarily for speech perception, and that the problem with tonal languages was that it introduced another layer of perception on top of speech perception, which made hearing tonal languages much more difficult than English. This was a problem they were trying to address.

Been slow news weeks so far, nothing noteworthy. At last, something’s come up! Great that the inventor of a device that brought hearing to many people who needed it gained more recognition!

From: http://uninews.unimelb.edu.au/articleid_4223.html

Inventor of Cochlear implant wins Germany’s top neuroscience award

Media Release, Monday 21 May 2007

University of Melbourne scientist Professor Graeme Clark has received the 2007 Klaus Joachim Zulch prize for his research into neuroscience and the Cochlear implant, giving hearing to deaf people.

Professor Clark was awarded the prize for outstanding achievements in basic neurological research for developing the multi-channel Cochlear implant (Bionic Ear). He shares the prize with Dr John Donoghue who leads the brain science program at Brown University in the US.

The Zulch prize is Germany’s highest award in neuroscience, and is made by the Max Planck Institute which is ranked by the Times Education Supplement in 2006 as the top research institute in the world.

Over 80, 000 people in more than 70 countries around the world now use Cochlear implants to hear.

Professor Clark’s research in the Cochlear implant was first undertaken at the University of Sydney from 1967-1970, and then it flourished at the University of Melbourne when Clarke was appointed as Foundation Professor of ear, nose and throat surgery in 1970 till he retired from this position in 2004.

His research also received considerable support from the Bionic Ear Institute which Clark founded in the late 1980s and continued until his retirement in 2006.

The Cochlear implant would not have achieved such success if it were not for the excellent industrial development by the Australian firm Cochlear Limited and the crucial work at the Eye and Ear Hospital in Melbourne.

Professor Clark will be awarded the prize at a ceremony in Cologne in August 2007.

 Cochlear implants seem to be now paid for by insurance policies in the US.

In Singapore, it is still regarded as an ‘elective’ option, and parents or adults have to pay the full cost of the implantation which can potentially run up to $42,000 if they don’t manage to get the government subsidy, which is only given to 35-45 people a year.

From the San Diego Union-Tribune:

Biller at hospital was persistent with insurer

By Elizabeth Fitzsimons
UNION-TRIBUNE STAFF WRITER April 8, 2007
The day they turned on her cochlear implant,
Elizabeth’s eyes went wide, her eyebrows jumped and her 7-year-old face was alight.

“I hear that!” she said.
Elizabeth‘s mother, Laura, tells this story. And though nearly two years have passed, she still gets chills when she remembers that moment. How Elizabeth Shaw has changed since that day in August 2005. The second-grader now reads at her grade level, scores 90 and 100 percent on her spelling tests, and hears what her sisters and parents are saying.

Elizabeth, 9, has blossomed. That the implant, not covered by insurance, cost her parents $40,000 wasn’t easy to swallow. But Jon and Laura Shaw had been through so much. Since the premature birth of Elizabeth and her sisters, triplets who each have their own special needs, the Carlsbad couple have battled insurance companies, health care providers and school administrators.

This time, they saw no chance of winning. So the couple – he’s 53; she’s 49 – wrote a check to Rady Children’s Hospital for $30,000 and another for $10,000 to pay the anesthesiologist and surgeon. And then they moved on.

They didn’t know someone had taken up the fight for them until Jon Shaw answered the phone in January. It was Jamie Cha calling from the billing department at Children’s Hospital. Cha had a refund check from the insurance company for $25,000, she told him. Would he like to pick it up? Cha, the Shaws learned, had been working on their case for nearly 18 months, gradually proving to the insurance company, Pacificare, that the cochlear implant, an electronic device that improves the hearing of a person who is deaf or hearing-impaired, was indeed covered under the Shaws’ policy.

“I never expected to see any of that again,” Laura Shaw said.

It was simply a matter of how the billing was coded. From her cubicle in Kearny Mesa, where her children’s photos share space with Post-it notes and inspirational messages from fortune cookies taped to her computer, Cha called one Pacificare employee after another. She pored over the policy. She filed an appeal over the phone, then appealed again in writing.

“I felt, honestly, that it would probably be worthless in the end,” Cha said.

But she kept at it. A mistake had been made, and Cha, herself a mother of three, was going to fix it. She didn’t know much about Elizabeth Shaw. She didn’t know Elizabeth was one of triplets, or that she had hearing loss and was very nearsighted, or that sister Olivia was a Braille reader and sister Katy had a prosthetic eye and poor vision in the other eye.

“Every day I always think, ‘Gosh, if one of my kids gets sick, where am I going to come up with this money?’ ” said Cha, 25, who lives with her children and husband in south San Diego. “It makes you realize how lucky you are.”

Upon receiving the case in September 2005, Cha saw the hospital had been paid, and that the money had come from the family because the procedure wasn’t covered.

“I was like: ‘What in the world? What did the patient have done, and why is it so expensive?’”

She’d worked on large amounts before, but it had always been the hospital seeking the money. The most she’d seen a family pay was a $500 co-pay on a surgery.

“I reviewed all the procedure codes and looked at the contract with Pacificare, and it says right here it would be covered if we billed with the code,” Cha said.

How good it felt to give the family the news, Cha said. The hospital in turn congratulated Cha. And then it was back to work on all the other cases on her plate. Roger Roux, the hospital’s chief financial officer, was pleased with Cha’s success, but said the hospital expects these kinds of wins.

“What Jamie did here for this family is, believe or not, not unusual for us,” Roux said. “What is unusual for us is the dollar magnitude. “Billing to insurance companies in this day and age is very, very complex, and it involves lots of codes and prior authorizations. And insurance companies, as you can appreciate, scrutinize the bills very carefully.”

Once the Shaws had the check in hand, Laura Shaw was nervous about asking too many questions. But she was delighted to have the money back, especially now, as the family prepares to move to Templeton, a small town near Paso Robles. On Friday afternoon, the girls returned from school and dived into a bowl of popcorn. Olivia tapped away at her Braille laptop on a couch off the kitchen, and Katy and Elizabeth hovered over another laptop, where they took turns at a game that lets players design SeaWorld.

Since the cochlear implant, Elizabeth has jumped three grade levels. Still, there are gaps. She has difficulty with similar-sounding words, like “continent” and “consonant.” And she has trouble with words that have more than one meaning.

When Laura Shaw asked Elizabeth what grade she gets on spelling tests, Elizabeth answered that she was in the second grade. No, Laura Shaw said. What percentage? “One hundred percent,” Elizabeth said, smiling.

Cha and the Shaws haven’t met. It was just too far for the Shaws to drive. So Cha dropped the check in the mail.

And then she returned to her work.  

Cochlear regeneration is well on its way to be developed within our lifetimes, if the following news article is anything to go by (emphasis mine):

National Center for Regenerative Medicine researchers say that studies have shown noise-induced hearing loss is going to become the next big epidemic affecting our younger generation, though the effects won’t show until it is too late to treat. In addition to loud noise, certain cancer drugs or genetic factors can cause hearing loss in humans due to loss or faulty development of the sensory ‘microphones’ (hair cells) inside the ear – the cochlea.

Lost hair cells are not replaced and people exposed to these conditions face permanent hearing loss. Identification of the stem cells from the adult cochlea would be a major step forward to develop new therapeutic approaches to hearing loss.

Members of the National Center for Regenerative Medicine research team, Dr. Robert Miller and Dr. Kumar Alagramam, both of Case Western Reserve University School of Medicine, recently published research findings in Developmental Neuroscience which suggest new ways of treating hearing loss. These researchers have isolated “cochlear stem cells” located in the inner ear and already primed for development into ear-related tissue due to their proximity to the ear and expression of certain genes necessary for the development of hearing.

“Previous work in our lab with young-adult mouse cochlear tissue showed expression of genes normally found in stem cells and neural progenitors. This led us to hypothesize that cochlea harbors stem cells and neural precursor cells. Our work in collaboration with Miller’s lab supports our hypothesis,” Dr. Alagramam said.

They say that in early life, these precursor cells may be able to regenerate hair cells, but their capacity to do so becomes limited as the ear develops and ages. The team’s research is a major step in devising a therapy to reverse permanent hearing loss because it may lead to the activation of cochlear stem cells in the inner ear to regenerate new hair cells.

“Clearly we have miles to go before we reach our end goal, but the exciting part is now we can test compounds that could promote regeneration of hair cells from these precursor cells in vitro, we can study the genes expressed during the transition from stem cells to hair cells, and we can think of developing strategies for cell replacement, i.e. transplanting these cochlear stem cells into the adult cochlea to affect hair cell replacement in the mouse, by extension, in humans,” remarked Dr. Alagramam.

In this paper, Drs. Miller and Alagramam offer further evidence for the existence of cochlear stem cells in the mouse cochlea by confirming the ability to form ‘stem cell’ spheres in culture and by characterizing these cells in terms of neural and hair cell development using a panel of stem cell development and hair cell markers.

The formation of spheres from early postnatal cochlear tissues and their expression of a wide range of developmental markers unique to hair cells confirm the possibility that self-supporting hair cell precursors exist in or can be derived from the postnatal mammalian cochlea.

While further research is necessary, the researchers believe these precursor cells have the potential to regenerate the damaged hair cells and restore normal hearing.

The team has already begun animal studies to explore the use of cochlear stem cells in well-established hair cell ablation models and in deaf mouse mutants with predictable patterns of early hair cell loss. This line of research will evaluate the in vivo survival and differentiation of self-renewing cochlear cell populations and potentially lead to new therapies for the numerous individuals that are going to suffer from noise-induced hearing loss in the near future.

Cochlear Clinical Night

April 4, 2007

I have just come back from a Cochlear Clinical Night hosted in Singapore – the speaker was Brendan Murray, a cochlear implant specialist from Sydney. Some of you might be aware that he’s Lina Lim’s predecessor (Lina Lim is the area manager for South-East Asia), and was the first one to help set up Cochlear’s operations here in Singapore.

The talk was primarily for medical professionals and clinicians – but I found out and requested admission which was granted readily (thank you, you know who you are!) There were two main parts of the talk – clinical outcomes for Freedom, and the future of their implantable devices. Please take note scores provided below might not be accurate – they are from memory.

Cochlear did a Freedom trial on 71 postlingually deafened adults in North America. I think you should be able to know that results were fantastic according to them. Let’s go straight to the more exciting part- the implantable devices.

There are now apparently 3 new or upcoming implantable devices by Cochlear other than Freedom on the market – the Hybrid S, Hybrid L, and Auditory Brainstem Implant (ABI). The Hybrid implant is an alternative option for those who are worried about losing their residual hearing - it combines the benefits of both acoustic and electrical processing – in other words, it tries to combine the functions of a hearing aid and a cochlear implant. 

The Hybrid S measures about 10mm, and is jointly developed by the University of Iowa and Cochlear. Research results on Hybrid S have shown that pitch perception scores of trial recipients can be quite close to that of normal hearing (90% in some cases, as compared to 60-70% for Long Electrode/the traditional CI).

The Hybrid L measures about 16mm, and word recognition scores have apparently created a new industry benchmark – word recognition scores hit above 50% for 3 months postoperative implantees from just around 2-6% preoperative.

The Auditory Brainstem Implant (ABI) section was very interesting. It’s an alternative for people with cochlear implant failures, or are found to be unsuitable for cochlear implants – NF2 (Neurofibromatosis Type 2), cochlear asplasia, cochlear nerve agenesis, ossified cochleas etc. It’s implanted directly at the cochlear nucleus at the right side of the brain at the bottom (if I’m not wrong), allowing direct stimulation. However, trials found that there was stimulation of other parts of the brain that was not auditory in nature, causing side effects – dizziness, aches and pain in other parts of the body ie. eyes, chest, legs.

Personally, I felt that Cochlear needs to integrate pitch perception tests as part of their testing. Not only that, I was wondering about how a bilateral and a Hybrid would compare against each other on word recognition scores (although I’m sure a Hybrid wins hands down on pitch perception). I also felt that the ABI was a kind of dead end – it had many reported side effects, and there was no complete open set recognition of words for the postlingually deafened individuals – which says a lot. Not many benefited, and those who benefited still had to use lip-reading cues to aid listening. Nevertheless, some form of listening is better than none at all – only without side effects, however!

Nevertheless, the Hybrid represents a new advancement in cochlear implants for individuals with severe hearing loss. It is much better than the long-electrode traditional cochlear implant, judging from independent research and anecdotal experiences. Individuals with such hearing loss, and are worried about their residual hearing not being utilised need not worry further with this new CI.

Hopefully, for the rest of us who are already implanted, a fully implantable device or cochlear regeneration is not too far off in the future.

Advanced Bionics, Cochlear’s main rival, had more woes to contend with – several of their implants failed recently and they blamed it on one of their suppliers. This sent Cochlear’s share price soaring and presumably, celebrations with champagne at their HQ.

With further damage to their reputation - their third recall in 4 years – their quality control record seems to get spottier and spottier. Advanced Bionics needs to clean up their act if they want to compete on an equal level with Cochlear.

News from Reuters:

MELBOURNE, March 10 (Reuters) – Shares in Cochlear Ltd.,  the world’s top maker of hearing implants, soared 17 percent to a record high on Friday after its rival Advanced Bionics voluntarily recalled some of its implants.

In an “urgent recall” letter dated March 8, obtained by Reuters, Advanced Bionics told clinics that several of its implants had failed recently due to internal moisture, which it blamed on one of its two suppliers of a specific part that connects the sealed section of the implant with an electrode.

Advanced Bionics, owned by Boston Scientific Corp. said it would send out replacement implants with parts made by the better supplier.

Cochlear Chief Executive Chris Roberts said it was too early for the group to upgrade its full-year profit forecast on the back of its rival’s problem, as it was not yet clear how quickly Advanced Bionics would be able to replace the faulty implants.

“It’s a bit premature to make any assumptions about that at this stage,” Roberts told Reuters.

“The major benefit to us is the further reputational damage to Advanced Bionics rather than a particular market share move.”

Cochlear shares surged 17.2 percent to a new peak of A$55.01 in a flat market, surpassing the previous high hit in November 2001.

A recall of Advanced Bionics’ HiRes 90K implant in 2004 due to moisture problems helped Cochlear reclaim U.S. market share last year, which the group has built on further this year to around 70 percent with its newest implant, the Nucleus Freedom.

It was not clear how many implants Advanced Bionics had recalled this time, Roberts said.

Cochlear would have a better idea about potential gains when it hears from clinics whether they want more Cochlear implants or are just postponing operations while they await replacement implants from Advanced Bionics, he said.

Spokesmen at California-based Advanced Bionics and the head of Advanced Bionics’ auditory division, James Miller, did not respond to calls, and there was no note on the group’s product Web site (www.bionicear.com) about the recall.

“This is the third recall in four years, and is a disaster for reputation,” Citigroup said in a note to clients.

“We would expect Cochlear to gain the majority of the short- term market share and secure medium-term market share as ABC’s reputation slides,” it said.

Cochlear forecast in February that its core annual earnings would grow by 37 percent to at least A$80 million ($58 million) this year.

“You can assume people will upgrade their numbers because this will help Cochlear hold on to, if not gain, market share,” said an analyst with a fund manager who declined to be named.

In 2002, the U.S. Food and Drug Administration began investigating reports that showed a possible link between cochlear implants and a higher risk of meningitis, causing a CI manufacturer, MED-EL, to voluntarily take an implant model off the market. This link was confirmed in 2004 by a further study, that showed cochlear implants with a positioner did somehow increase the risk of bacterial meningitis. Cochlear implants without a positioner still carried a higher risk of bacterial meningitis, but not as high as those with positioners. Advanced Bionics had stopped implanting models with positioners after July 2002, and MED-EL voluntarily took their model off the market.

There is now evidence to show an association between severe hearing loss and meningitis, giving parents more to worry about. Severe hearing loss may indicate an onset of meningitis, as the incidence of bacterial meningitis has been shown to be 5 times higher in children with severe hearing loss.

So parents, if your children have hearing loss, do get them vaccinated against meningitis today. The efficacy of the vaccine is between 85-100%, and the duration of the efficacy is approximately between 3 to 5 years.

There is a report on New York Times that Medtronic, a company manufacturing medical devices, is launching a possible take over bid for Cochlear Ltd.

Article linked. For those lazy to click, the full article is archived below:

Cochlear CEO: Takeover Bid Possible

MELBOURNE, Australia, Mar 29, 2007 (AP Online via COMTEX) — The chief of Australian hearing implant company Cochlear Ltd. said Thursday he had “no idea” if U.S.-based Medtronic Inc. is interested in taking it over, but that such a bid was possible.

Broking house ABN Amro said in a research note Cochlear could be an “attractive takeover candidate” for Medtronic, which is currently seeking acquisitions.

“I guess as a public company it’s always a possibility, but I don’t think there’s any magic in this” scenario, Cochlear CEO Chris Roberts told Dow Jones Newswires.

He said he had “no idea” if Medtronic could be interested and hasn’t been approached. Roberts also questioned why ABN AMRO’s target price on Cochlear was still below the company’s share price if it considered Cochlear a potential target.

A spokeswoman in Australia for Medtronic, which is based in Fridley, Minnesota, said the company doesn’t comment on mergers and acquisitions.

Cochlear’s share price has more than tripled in the past three years. The company, which competes mainly with U.S.-based Advanced Bionics, a unit of Boston Scientific Corp., holds around 70 percent of the global market for hearing implants.

Cochlear shares traded at around 63 Australian dollars on Thursday, valuing the company at A$3.46 billion ($2.8 billion). ABN AMRO has a A$57.25 target price on the stock, raising it this week from A$54.50 to take into account the possibility it may be a target.

Medtronic, which has market capitalization of around $56.2 billion, makes a wide range of medical devices in the cardiac, neurological and orthopedics businesses, but doesn’t have a presence in the hearing implant market.

ABN AMRO analyst David Stanton said the workings of the cochlear implant are similar to Medtronic’s spinal stimulator and it could benefit from Cochlear’s expertise in research and development and manufacturing.

Copyright (C) 2007 The Associated Press. All rights reserved.

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