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The Origin of the Completely in Canal Hearing Aid design, and the Hearing Assist HA-1800

The Origin of the Completely in Canal Hearing Aid design, and the Hearing Assist HA-1800

Back in the early 1980’s, Larry Hagen and Johan Carlson, two hearing aid engineers in Minneapolis, were closely following the development of custom in-the-ear (ITE) hearing aid designs and the increasingly advanced miniaturization of hearing aid components. The ITE design was growing in popularity due to not only the lower profile look, but also the science behind frequency amplification. Placing the hearing aid microphone in the concha bowl of the outer ear (pinna) and the receiver within the ear canal leads to more natural sound amplification and better high frequency response. As Hagen advises, “The outer ear functions as a natural preamplifier to deliver sound to the ear drum. This is what the typical person would consider natural sound. So if a hearing aid is fit on a patient, we want to deliver a final sound to the ear drum that mimics this natural effect of the pinna and ear canal.

In the mid 1990’s, as these ITE designs continued to be refined, deep impression taking techniques combined with smaller hearing aids that fit Completely In the ear Canal (“CIC”) became the latest in hearing aid innovation. Hagen’s company, Micro-Tech Hearing Instruments, became one of the first companies in the United States to be granted 510k approval to produce, market and sell this new type of hearing aid design.

The better the hearing aid device can produce high frequency gain at the ear drum, the better the patient may be able to understand spoken speech,” Hagen continues. “That is because of the make up of the English language. Most of the energy that accounts for adequate speech perception lies between about 60Hz to around 6kHz. 95% of the energy lies below 1kHz and only 5% lies above. However, the higher frequencies give us about 60% of our ability to understand. Typically most patients show high frequency hearing loss either through aging (presbycusis) or from noise exposure. As a person develops high frequency hearing loss they start to misunderstand. For example, ‘What kind is it?’ may be misconstrued as ‘What time is it?’ because the patient has to guess about the ‘k’ because they couldn’t hear it. As the loss gets worse and worse the problems of understanding gets worse and worse.

The main problem with custom ITE hearing aids has been the very nature of its name, custom. They were very expensive to produce as each shell had to be made individually. This uniqueness made it very hard to do preprocessing of subassemblies. Remake rates were very high due also to poor ear impression taking techniques amongst the hearing aid professionals.

So the task that Larry and Johan partnered up to take on was how to create comfortable fitting ITE devices that retained the acoustic, cosmetic and venting benefits of well fitted custom ITE devices but that could be mass produced. Also there would be no need for ear impressions. In effect, one size that fits most, if not all users.

Because of our 30 years of custom ITE production we had a very good idea of what the average ear size was,” says Carlson. After numerous size and shape shells were produced and tested on people, the partners succeeded in developing two new proprietary designs that met the following criteria:

  1. Functions as well and in many areas better than BTE hearing aids (especially in the high frequency ranges)
  2. Be comfortable and will not fall out of the ear
  3. Discreet (barely detectable)
  4. Uses anatomy of the ear to determine fit without an ear impression (one size fits almost everyone)
  5. Could be mass produced

As a result, the patented design of the C-Shell and the Teeny (now Hearing Assist HA1800) were born. Each with advantages that would appeal to any ITE hearing aid wearer. The HA1800, being a CIC hearing aid, is perfect for people that have difficulty hearing high frequencies and is almost invisible as it sits deeper in the ear. It is hardly noticeable and a universal fit, fitting either ear perfectly. The C-Shell as its name implies is shaped like a “C” or crescent and sits in the concha (bowl) of the ear creating a fit that is “trampoline proof”, i.e. supported by at least two surfaces of the ear creating a confident and comfortable fit. The C-Shell can be used with or without an ear cap depending on your hearing loss. The C-Shell design is flexible; it can be developed to perform many functions – hearing aid, sound suppressor, tinnitus masker and more.

The HA1800 and the C-Shell both have unique designs that comfortably fit the masses. When Larry & Johan teamed with Hearing Assist, they combined these innovative designs with the latest digital signal processors and world class customer service to create the most comfortable, discreet and complete ITE hearing aids while keeping the prices affordable!

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