Hear So Good Blog

The Achilles Heel of a Good Hearing Aid Fit

July 6, 2015

One of the greatest challenges when fitting hearing aids can be finding the best method to couple the device to the patient’s ear. For some individuals the solution is straightforward but for many, the audiologist must combine keen observation, experimentation, creativity, good problem-solving skills, and a lot of patience.

I personally enjoy this part of the job. Many audiologists would think the task mundane and not really see the value such practice brings to providing a patient with devices that will be comfortable and easy to use and maintain. Many audiologists, as many individuals these days, get overly enamored with advanced technology and think that sophisticated products will solve everything.

Hearing Aids Are Not Consumer Electronics

I recall my grandfather who had the misfortune of losing a leg in a freak accident. He got around just fine using a prosthetic limb. From my childhood I remember him going back to the prosthetist many times because either the prosthesis would not fit snugly and be stable enough – or it would be uncomfortable and even painful. And then whenever he would “upgrade” to a newer model he would have to go through the fitting process all over again.

I see fitting a hearing aid, an assistive device which must be coupled to a human body part (the ear canal), as a similar process. The trend in hearing aid design has been to use receiver-in-the-canal (RIC) or receiver-in-the-ear (RITE) technology. Different manufacturers use different terminology but the devices are the same. With this technology the hearing aid speaker actually fits in the ear canal and an electrical wire connects it to the hearing aid, which is placed behind the ear. Before the advent of this technology, conventional behind-the-ear (BTE) hearing aids had the speaker in the body of the hearing aid and a small silicone hose would pipe the sound form the hearing aid to the ear canal. The tubing would be secured in an earmold, a piece of acrylic, vinyl, or silicone that was custom shaped to fit comfortably and securely in the ear canal. These BTE devices today are sometimes referred to as receiver-in-the-aid (RITA) models.

RIC Hearing Aids. Stock tip on the left (blue), Custom tip on the right (red).

Standard BTE hearing aids with #13 tubing are still widely available and currently fit as they are a better alternative for some individuals. They are more reliable and easier and cheaper to maintain as the speaker is not exposed to the hostile environment of the ear canal. Conventional BTE’s typically are larger than their RIC counterparts. Bigger devices, although not as cosmetically appealing as RIC models, enable larger controls for adjusting volume and changing programs, and are easier to operate by fingers with arthritis or reduced touch sensitivity.

Conventional BTE with #13 tubing.

Conventional BTE with #13 tubing.

Detail of #13 tubing secured in a custom earmold.

 

Common Complaints When Coupling Devices are Poorly Selected

  • “It’s hard to get my hearing aids in”
  • ​“My ears hurt or are itchy or sore”
  • “My hearing aids keep popping out”
  • “My own voice sounds strange”
  • “I can hear myself chewing too loudly.”
  • “My ears feel plugged-up”

The Good and the Bad of Stock Ear Tips

RIC devices and even conventional BTE’s with slim-tubes can be fitted with custom earmolds or stock ear-tips. Slim-tubes are more cosmetically appealing than conventional #13 tubing but can limit amplification in the high frequencies, and may not be suitable for certain types of hearing loss. Many providers do not equip RIC products with custom ear-tips – and here is why – time and money. Custom ear-tips require an ear impression to be taken. This process requires extra time and labor in the office to take the impression, mail the impression to the earmold lab, wait for it to come back, and possibly modify the earmold in-house or send it back to the lab for a remake.

Slim-tubes with stock ear-tip. Slim-tubes are more cosmetically appealing than #13 tubing but can limit benefit for individuals with high frequency hearing loss.

 

Additionally, many providers are not comfortable taking ear impressions – next to cerumen removal it is the most invasive procedure audiologists are licensed to perform. In order to get a good ear impression a cotton or foam dam must be inserted deeply into the ear canal about 2/3 of the distance between the ear canal opening (aperture) and the eardrum. Using good lighting a skilled audiologist can very safely perform this task.

There also is a tendency for large providers, especially the big chains, to stock hearing aids. They buy them in bulk so that they can get deep discounts from the manufacturers. They will then fit devices with stock ear-tips on the same day they are sold and neglect to consider whether the patient would be better served with custom ear tips. This way the providers gets payment in full right away. There is also an industry perception that if a patient has to wait a week or more for earmolds to arrive to be fit; the patient may change his/her mind or shop somewhere else.

Choosing the Right Coupling Method

Now I am not saying that stock ear-tips are not fine for some people. They are. I have fit many patients with these tips. These tips come in different sizes and configurations (see below) but the problem is that they are all essentially round.

A variety of stock ear-tip types.

 

Many people do not have round ear canals and so a good fit will be a compromise with any stock ear-tip size. In addition, patients must take care to insert ear-tips to the same depth every time they are used; otherwise, the intensity of sound reaching the eardrum and perceived speech clarity will vary. Since custom ear-tips are easier to insert the same way every time, more consistent benefit is realized.

Ideal ear canal geometry for stock ear-tips.

Examples of poor ear canal geometry for stock ear-tips.

 

At Hear So Good we look at the following factors to initially chose the most appropriate ear coupling:

  • Any skin sensitivities
  • Geometry of the ear canal
  • Shape of the pinna – the “bowl” (concha) and outer part of ear
  • Tolerance to pressure in the ear canal
  • Occlusion tolerance

Conclusions

While advanced hearing aid features have the potential to significantly help hearing impaired individuals hear better, the main factor that can limit the benefit is the method used to couple the device to the ear canal. Patient comfort and convenience are equally important – a hearing aid needs to be worn to help – and if a hearing aid is difficult or annoying to use, or is uncomfortable, it will sit in a drawer and benefit nobody.

… Stay tuned for our next blog post which focuses on how the following patient factors impact our choice of hearing aid recommendation:

  • Visual acuity
  • Manual dexterity
  • Fingertip sensation
  • Spatial-visualization ability