What to Consider When Fitting Asymmetrical SNHL?

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Answer

Some fitting ideas to keep in mind when dealing with asymmetrical SNHL include: 

• Do not say "no" until you know. The only way you know that an ear cannot benefit from amplification is when you attempt to fit a hearing aid on that ear. There is no justification for predicting that an ear cannot use amplification. It only requires a little bit of time investment by you and the patient.
• Aim for a fused, binaural image. Although you have asymmetries, with two ears that are working at different levels, the whole idea is to merge those two ears to work together in an effective way.
• Targets are a place to start. However, do not be surprised if you end up using less gain in the poorer ear. Often, the ear that is working better is the ear that is going to be doing the heavy lifting, as far as communication goes. The idea is to incorporate the poorer ear, but not compete with the better ear. Frequently, you'll end up backing down the gain on the poorer ear, and your temptation is to drive the gain up. The problem with that is, as you increase the gain, you also have the potential to increase audible distortion in that ear. Although targets are a reasonable place to start, through the adapter process, you might end up finding that you have to back off in order to get that fused auditory image that the patient is seeking.
• Consider serial monaural fittings. Although you may target a patient with a bilateral asymmetrical hearing loss as being a patient who can wear hearing aids in both ears that does not necessarily mean that you have to fit both hearing aids at the same time. When we fit hearing aids, it is assumed that we should fit them both at the same time. However, it is important to remember that a lot of these patients have one ear that works better than the other. Somehow, you are trying to get them to use both ears together. What can sometimes happen is that if you try to fit both hearing aids at the same time, you can create confusion: Confusion about which ear is hearing what, and which ear needs adjustments, and how the whole thing is coming together. Consider a situation where you target the better ear first. You know you are going to put a hearing aid on that ear. The better ear is probably going to do the heavy lifting for the patient. Once you are certain that the hearing aid is successful (after one or two weeks), then amplify the second ear. When you add that hearing aid to the second ear, what you are trying to accomplish is having that ear contribute and be part of the fitting, but never to the point where it is competing with the better functioning ear. You may not utilize as much gain in the secondary ear, because you already have a successful fitting in the better ear. This case is not viewed as a traditional binaural fitting; rather should be considered as two monaural fittings leading to a binaural result.

This Ask the Expert is an excerpt from Complex versus Standard Fittings: Part 2. Learn more on the Oticon Expo Page on AudiologyOnline.