Forward-Thinking Design

A cochlear implant is an implantable electronic device that lets severe to profoundly deaf individuals hear.  Anatomy of the ear shows the outer ear with the pinna and ear canal; the middle ear with the eardrum and the hammer, anvil, and stirrup; and then the inner ear, made up of the inner ear (cochlea), vestibular system, and auditory nerve. The combination of all these parts of the ear is what enables individuals to hear, and because of the detailed makeup of hearing components, there are four types of hearing loss: conductive, sensorineural, mixed, and neural.

Cochlear implants, the specialty of engineering research at MED-EL Corp., addresses the hearing loss associated with a damaged cochlea – especially the highly sensitive hair cells covering the cochlear, which are what moves when stimulated by sound.

While a hearing aid functions for many areas of mild to moderate hearing loss, cochlear implants go right to the source of damage and work to be a permanent solution to bring sound – at a range of pitches – back to the patient.

Dedicated Roots
Dr. Ingeborg Hochmair and Prof. Erwin Hochmair, co-founders of MED-EL, began working the development of a cochlear implant in 1975 in Vienna, Austria.

“Being inventors, or something like that, makes you stubborn and you want to see it turn into a success and be used by people to improve their quality of life,” says Dr. Hochmair, current CEO of the company, regarding how the company came to life in March 1990 in Innsbruck, Austria.

It was that stubborn determination to develop the next advancement that resulted in MED-EL having their current 28 locations, with implants occurring in nearly 100 countries. Approximately 160 employees work in the design and development area of MED-EL, with an additional 60 in engineering.

“Development and manufacturing occurs in Innsbruck,” Dr. Hochmair states. “We have a cleanroom facility for the implants while the general manufacturing facility is for production and assembly of the non-implantable external device.

“In addition to the manufacturing, this is where the research and development occurs, along with the various R&D cooperation that occurs,” Dr. Hochmair notes. “What we do is we take findings from basic research and implement that into our newest products as well as initiate new research that we need for the next generation. So, we have these collaborations with research institutions and clinics to advance our products.”

1. Flex Tip Technology – Design of the Flex Tip of the electrode array is for atraumatic insertion and protection of the delicate neural structures of the cochlea. 2. Wave-Shaped Wires – Wavy instead of straight, the wires of the electrode array are particularly soft and flexible. 3. Optimal Number of Contacts – Achieving optimal balance between the number of contacts and the appropriate distance between them increases flexibility and limits channel interactions.

Maestro’s Perfection
MED-EL offers the MAESTRO Cochlear Implant System, combining the company’s Complete Cochlear Coverage, FineHearing, and Automatic Sound Management technologies.

“We have had several generations of our cochlear implant, and are now on generation number five, which is the actual stimulator,” Dr. Hochmair notes. “The importance of each change in the generation and development is because the size of the cochlea varies from patient to patient, as well as the amount of residual hearing. Most recently, we introduced the FLEX28 and the FLEX24, where the FLEX means they are very soft and can surgically insert into the cochlear without causing a lot of trauma or damage to the delicate structure of the inner ear, while preserving any residual hearing the patient has.”

The new length availability enables coverage of more than 95% of all different cochlear lengths that exist in patients, an important factor when knowing how hearing works. If there is coverage of the entire length of the cochlea with the neural elements, success is more likely in the adaptation of the frequency range provided by the stimulation. Hearing occurs with low pitch toward the end of the cochlear and high-pitch sensations near the beginning, so full coverage does not require patients to adapt to a smaller range than traditional hearing enables.

The softness of implant is attributable to the wave-shaped wires and very thin platinum iridium wires, which also, at the end of the implant has tiny flat contacts that represent the electrode contacts. This entire structure embeds in soft silicone, making the entire implant thin and flexible, which is what enables the simplified and successful insertion across the vast distance of the cochlea. Internally, the components have remained the same basis of material since its first development, but where the most changes have occurred is with the external component – the audio processor – because of advancements throughout the years with regard to the microelectronics that drive the electrodes inside. Although the external device appears as a hearing aid, complimenting this component is a coil, which makes sure that the signal, as well as the power for the implant, transmits through the skin without interruption.

Therefore, what began as a large device due to processor sizes, through engineering and R&D, there has been dramatic reduction in power consumption, as well as the size of the behind-the-ear pieces. Today, the Opus 2XS external component – the smallest and lightest instrument on the market – only requires two hearing aid batteries, whereas before all the processors required three batteries.

The Soundbridge’s FMT converts the signal into mechanical vibrations that directly stimulate a middle ear structure (e.g., the ossicular chain) causing it to vibrate.

Hearing Lesson
“A cochlear implant is an implantable electronic device that lets severe to profoundly deaf individuals hear,” states Director of Education and Corporate Communications, Darla Franz. “If the cochlea is not working properly, surgeons can implant this device – a very soft electrode array – into the cochlea, which is a very delicate organ, with many tiny and delicate membranes and hair cells inside. Essentially then, the cochlear implant takes on the role that working hair cells do.”

As Franz goes on to explain, where the industry is today from where it started is way advanced. “Not only have implants become more technologically advanced from the very beginning of just single-channel devices, but today we are able to offer a variety of different pulse patterns in order to trigger different kinds of perceptions. With research and development, we have really taken patients from the very early days – where they might have been able to tell that there was a person talking but were not able to understand the sounds, necessarily – to 40+ years later, patients very much do understand, without visual clues. They understand speech in noise, and now, our research is even helping us learn how to trigger specific types of pulse patters in order for a person to be able to understand and appreciate music.

“We are going well beyond the original idea of just seeing if we can get the brain to recognize a sound, as this research is helping in the understanding of how to trigger these perceptions using electrical stimulation with the implant in the cochlea.”

1. The MAESTRO Cochlear Implant System can be used effectively by both pre-lingually and post-lingually deafened children and adults. 2. The 28mm FLEX 28 electrode array offers surgeons additional options for atraumatic insertion, providing the best possibility for preserving the delicate structures in the cochlea. 3. Soundbridge’s Vibration mimics the action produced by sound waves moving through the ear canal. 4. The Vibrant Soundbridge Middle Ear Implant System directly causes the middle ear structures to vibrate.

Future Challenges
“When we look into a child’s future, we realize that it is probably very likely that as electronics devices change so rapidly, these patients will end up having more than one implant. So, going back to what was mentioned previously, preservation of the cochlea from the first implant is important,” Franz explains. “I think the larger industry perspective was always if the cochlea is not working, let’s put an implant in and make it work, without really worrying about the residual damage done. Dr. Hochmair’s vision was always very different, right from the start. Her vision was always that this is a very delicate structure and we must be as careful as possible which is why the softest, most flexible electrodes are the mark of MED-EL technology.

“We look at not only what trauma might occur when implanting the electrode, but how to minimize any trauma if it is removed sometime down the road. If we measure hearing prior to the implant and then after the implant, and if we find that this hearing – although perhaps not functional but hearing that is present – is still there after implantation, it shows that no damage resulted from surgery,” Franz notes.

The company is beginning to explore what happens for individuals that, for whatever reason, have already had one implant removed and another put in. If there is no damage noted to the residual hearing they have, it further supports the direction of developing the soft and flexible electrodes of the MED-EL technology, and supports the company’s drive to provide electrodes that can be inserted with little damage.

“Beyond the need to offer cochlear implants with minimal damage to existing structures is the need for our products to be backward compatible. So, I think what really differentiates our company from others in the industry is this forward-thinking design we offer, knowing it is important to get results without sacrificing future advancements,” Franz explains.

Positive Outlook
Dr. Hochmair is a strong believer in the company she and her husband founded, priding themselves on having brought many new products to market that are innovative and enrich the lives of those with hearing loss. Her goal has always been to offer implantable solutions for all types of hearing losses and all amounts of hearing losses – developing not only the cochlear implants that work on electrical stimulation but also middle ear implants that work via vibratory stimulation, addressing the large range of needs in the hearing loss community.

It is with this dedication and vision that Hochmair and the engineers at MED-EL continue to research and develop technology that will advance this field – such as combination electric and acoustic stimulation devices, something currently in clinical trial – as well as having other implantable solutions and goals for the future.

 
Med-El Corp. 
Durham, NC 
www.medel.com