by Neil Bauman, Ph.D.
One of the reasons many people are not happy with their new hearing aids is because their hearing aids have not been properly adjusted to fit their specific hearing losses.
Often, the audiologist or hearing aid dispenser adjusts your hearing aids according to the manufacturer’s fitting algorithm for your hearing loss. Unfortunately, this algorithm does not necessarily reflect the hearing prescription you really need.
If your audiologist does not do “real-ear testing”, she will never know whether or not your hearing aids are set up properly for your ears.
With real-ear testing, your audiologist puts a tiny microphone into your ear canal, then inserts your hearing aid. A computer runs some automatic tests and the results are shown on the screen.
The output shows both a graph of what your prescription should be, and what your hearing aids are really putting out. Now your audiologist can see what she needs to “tweak” in your hearing aids to properly give you the amplification you need at each of the speech frequencies.
How important is this? Consider this. A recent study using one hearing aid manufacturer’s fitting algorithm was compared with the results of real ear testing. The shocking results show that less than 12% of the time were the results judged to be “clinically similar” when comparing the manufacturer’s values to the actual real-ear measurements.
Nancy Aarts, Ph.D., the author of this study asserts:
This study suggests that adult hearing aid fitting protocols should include the use of actual real-ear probe-microphone measures to verify hearing aid fittings. Reliance on [the manufacturer’s protocols] may result in insufficient output of most hearing aid users, as well as over-amplification of high level inputs for some hearing aid users.
What this means is that if you want to know that your hearing aids are fitted properly, you need to insist on having real-ear testing. If your audiologist doesn’t do real-ear testing, find one that does. It’s that important.
The above study was reported in the article “The Accuracy and Clinical Usefulness of Manufacturer-Predicted REAR Values in Adult Hearing Aid Fittings” The Hearing Review. November, 2005.)
