MedEl Presentation at 2003 ALDAcon

This is the third in a series of articles about the cochlear implant (CI) presentations at the 2003 ALDAcon in Las Vegas. This one is discusses the presentation by MedEl's Ellen Apostolakis. The previous two articles were about presentations by representatives of Cochlear Corporation and Advanced Bionics.

Here are some quick facts about MedEl.

- MedEl is a privately held company based in Austria.
- They produce a behind-the-ear (BTE) CI that doesn't look like a hearing aid.
- They pride themselves on the flexibility of their CI system.
- They are proud of their record of devoting 34% of their revenues to research and development.
- They entered the US market in 1998.
- They provide a remote consultation service, which allows experts at MedEl to see the same information about a client's CI that the audiologist sees.

They offer four different electrode arrays, each designed for a specific situation: regular, medium, split and compressed.

Their standard array, called the Combi 40 + 24 array, has 24 electrodes placed along 26.4 mm. This is much longer than the arrays of other CI manufacturers, which are about 20.9 mm. The additional length enables a deeper insertion into the cochlea, which provides responses at lower frequencies. (An insertion of 20 mm provides a frequency minimum of about 250 Hz). The ceramic array is only 4 mm thick, which promotes minimum disturbance of the cochlea.

The compressed array also has 24 electrodes, but places them over 12.1 mm. This array is useful when only restricted insertion into the cochlea is possible.

The split array is used for ossified cochleas.

The medium array, at 20.9 mm, is the same length as the arrays of other CI manufacturers, and is used for replacement of existing CI arrays.

MedEl is cognizant of the desire to minimally disturb the cochlear structure during electrode insertion. While all insertions will result in some damage to surviving hair cells and other cochlear components, their atraumatic electrode design supports the preservation of those tissues to allow for possible later use. They are working on an even less intrusive electrode design.

MedEl is the only CI with which some MRIs do not require magnet removal. The MedEl magnet is currently approved in the U.S. for a magnetic field strength of 0.2 Tesla, which is the standard strength for an open air MRI. In Europe, the magnet is approved for field strengths of up to 1.5 Tesla, which is the standard strength for a conventional MRI. MedEl has applied for similar approval in the U.S. An MRI should not be performed until 6 months after the CI surgery, to allow full healing of the magnet site, and they do ask that you contact MedEl before having an MRI with the magnet in place.

The MedEl system uses CIS+ processing, and is FM compatible. The adaptable external system includes five options, and every patient gets all five.

The "standard" option uses a straight battery pack, which sits behind the ear like other BTE processors. With this option, the CI looks more like a short pencil than a hearing aid! This option requires three 675 batteries, which last for 3 to 5 days. Battery duration is not dependent on the CI map or program.

Another option is the angled battery pack. With this option, the CI looks more like the other CIs, but the sharp angle contrasts with the smooth curve of the other manufacturers' models.

A third battery option is called the Children's Battery Pack, which is a smaller battery pack than standard. As the name suggests, it's primarily intended for children.

Another option is a remote battery pack, which attaches to the clothing and uses AA batteries, either disposable or rechargeable. This system is ideal for people on limited income, because a pair of rechargeable batteries will last for up to eight years!

The final option is called the Baby option, because it was originally intended for young children. Using this option, the processor is pinned to clothing, rather than being worn behind the ear. It's also a great option during sports or other vigorous activities.

The MedEl CI comes with lots of accessories, including covers and cables. It currently comes in either charcoal or beige, and colors are coming soon.

The input dynamic range is 75 db, from 25 dBs to 100 dBs. This is actually implemented as a 55 db window that slides 20 db, depending on the level of the environmental noise.

Everything that MedEl makes is backward compatible to their very first system.

Current research topics include:
- Drug Delivery - the capability to deliver medications directly to the cochlea through the electrode array.
- Electroacoustic Stimulation (EAS) - This is a fancy way of saying a hybrid hearing system in which a conventional hearing aid supplies low frequencies and a CI with a short array applies the high frequencies. Initial studies with these systems are very encouraging, with subjects doing well in noisy situations.
- Bilateral CIs - CIs on both ears
- Fully Implantable CIs - MedEl recently purchased Vibrant Soundbridge, who have a working implantable microphone. And they have a 15 year exclusive licensing agreement with Epic Biosonics, who have a fully implantable CI.