7 Tips for Hardwiring Verification and Validation Into Your Hearing Aid Fittings Why do audiologists avoid probe microphone real-ear measurements in hearing aid fittings? Here’s how to make it a no-brainer in your practice. All Ears on Audiology
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All Ears on Audiology  |   January 01, 2018
7 Tips for Hardwiring Verification and Validation Into Your Hearing Aid Fittings
Author Notes
  • Erika Shakespeare, AuD, CCC-A, is the audiology program manager for the Idaho Elks Hearing and Balance Center in Boise. She works with the National Center for Hearing Assessment and Management as a network audiologist for the Pacific Northwest and has a part-time private practice. She is an affiliate of ASHA Special Interest Group 6, Hearing and Hearing Disorders: Research and Diagnostics. shakespe@slhs.org
    Erika Shakespeare, AuD, CCC-A, is the audiology program manager for the Idaho Elks Hearing and Balance Center in Boise. She works with the National Center for Hearing Assessment and Management as a network audiologist for the Pacific Northwest and has a part-time private practice. She is an affiliate of ASHA Special Interest Group 6, Hearing and Hearing Disorders: Research and Diagnostics. shakespe@slhs.org×
Article Information
Hearing Disorders / Hearing Aids, Cochlear Implants & Assistive Technology / All Ears on Audiology
All Ears on Audiology   |   January 01, 2018
7 Tips for Hardwiring Verification and Validation Into Your Hearing Aid Fittings
The ASHA Leader, January 2018, Vol. 23, 18-19. doi:10.1044/leader.AEA.23012018.18
The ASHA Leader, January 2018, Vol. 23, 18-19. doi:10.1044/leader.AEA.23012018.18
Audiologists know that verification of the hearing aid fitting with real-ear measurements is not only best practice, but should be a standard of care. Too many of us trust that the gain curves (the gain for soft, medium and loud sounds) in vendors’ software are accurate and represent what’s really happening in patients’ ears. Using an independent real-ear system for verification of the output of a hearing aid ensures that you know what is actually occurring in the ear canal and at the point of the eardrum.
Many audiologists still rely on manufacturer algorithms to improve patients’ initial acceptance of the devices. The algorithms that hearing aid manufacturers use are based on settings that are least likely to result in a product return, and often these settings are below audibility targets, which will increase initial user acceptance. But people resist change, even when they need it most, and may be hesitant to adjust audibility.
We do this despite knowing that these targets are based on averages, and that the person sitting in front of us may not benefit optimally from the default configuration. Perhaps we use default settings because we think it is faster or because we trust our manufacturers. Or maybe because we think we are smarter than scientific evidence or because we think we’re too busy.
I am an optimist, however, and believe we can change our ways. I believe that we will always strive to be better versions of ourselves, on a constant trajectory of improvement. I also believe that if we can engineer our environment to make it easy to do the right thing, then it is more likely that we will actually do the right thing.
Let’s face it, years of studying human foot-traffic patterns has demonstrated that we will cut corners to find a shorter way to point B, even if it destroys the lawn. So let me share some ways I’ve found to seamlessly and painlessly incorporate real-ear measurements into routine fittings. But first, let’s consider a little history.

Audiologists know that verification of the hearing aid fitting is not only best practice, but should be a standard of care.

Why do real-ear measures?
Back in 1985, when probe microphone systems emerged, the industry was sure that real-ear measures validating hearing aid fittings would become the standard. Probe microphone systems allow the audiologist to insert a small microphone in the ear canal to measure the sound pressure at the level of the ear drum. Before the widespread availability of probe microphone measures, we had to rely on patient self-report for comfort and loudness of a hearing aid.
However, the promise of real-ear has not been realized: In 1998, H. Gustav Mueller, Vanderbilt University audiology professor, published a survey in the Hearing Journal illustrating that only about half of clinicians with access to the measures actually used them (see sources below). Repeated surveys since then have shown some increase in audiologists’ use of a tool once expected to become as ubiquitous among audiologists as wireless connectivity is among today’s hearing aid users.
For audiologists wary of incorporating real-ear measurement into hearing aid fittings, see these three phrases from audiologist Denis Byrne on self-evaluating your current procedures (see sources):
  1. If you can’t write down the rules you use, you probably don’t understand what you do.

  2. If it is not written down, no one else can do it and no one can test whether it is better or worse than an alternative approach.

  3. If you can’t evaluate your procedure, you can’t improve it.

Connect your prescription targets with the real-world goal the patient has set for themselves.

Get real (ear)
Although ASHA’s 2016 Audiology Survey indicates that 79 percent of respondents who fit and dispense hearing aids verify performance using real-ear measures (see sources), we can do better—and we can do it by making real-ear a built-in part of our practice. Here are seven strategies that I have used to hardwire verification and validation into hearing aid fittings.
1. Define the undefined.
Write down your hearing aid fitting process for you and for your patient. Include the steps of the fitting process in your purchase agreement, on your website and in writing. Be transparent in your process and demonstrate that you are more than a vending machine dispensing widgets. I include the verification and the validation of the hearing aid fitting and even spell out what that process looks like.
2. Allow for flexibility in your process.
Don’t let the unexpected derail you. If the fitting appointment needs to be simplified to HIO (hearing instrument orientation) basics and you run out of time for real-ear, schedule it as your first activity at the follow-up in one week, or even the next day.
3. Empower the patient to be part of the process.
Give patients the power to hold you accountable. Have the patient help you write their listening and hearing goals and what steps it will take to achieve them. Help the patient set goals that are SMART: specific, measurable, attainable, realistic and time-bound.
4. Keep it real.
Do you know anyone who uses the hearing aid manufacturer optimized fitting algorithm and then tries to match the settings to NAL-NL2 (National Acoustics Laboratory) or DSL (Desired Sensation Level) targets? Use an evidence-based verified target as your baseline starting point for setting hearing aids. If the manufacturer claims their algorithm works magic, ask for the peer-reviewed research that supports their method. (Twenty subjects providing subjective feedback is not strong evidence.)
5. Set specific tasks for each follow-up visit.
The first follow-up appointment isn’t just to tweak the hearing aid, it is to evaluate the function of the hearing aid on the patient’s ear and identify opportunities to enhance the listening. The second follow-up isn’t just to close out the trial period—it’s the perfect opportunity to demonstrate all the benefits of the hard work you both put into the fitting and acclimatization period.
6. Connect the goals.
Connect your prescription targets with the real-world goal the patient has set for themselves. You are the knowledgeable coach helping them to achieve those goals.
7. Select a validation tool that is simple and meaningful.
I like the IOI-HA (International Outcome Inventory for Hearing Aids) in conjunction with aided and unaided speech-in-noise testing to tie it together for the patient. This seems to work best at about four to six weeks post-fit. I schedule the appointment as the HAV (hearing aid validation) appointment. The patient looks forward to this appointment because it is where they can objectively see the benefits they’ve been experiencing subjectively for the past month. It is like the final bow on the gift of hearing and listening that they have given themselves.
Sources
American Speech-Language-Hearing Association. (2016). 2016 Audiology survey. Retrieved from: http://www.asha.org/uploadedFiles/2016-Audiology-Survey-Clinical-Focus-Patterns.pdf.
American Speech-Language-Hearing Association. (2016). 2016 Audiology survey. Retrieved from: http://www.asha.org/uploadedFiles/2016-Audiology-Survey-Clinical-Focus-Patterns.pdf.×
Mueller, H. G. (2015). 20Q: Today’s use of validated prescriptive methods for fitting hearing aids - What would Denis say? Audiology Online. Retrieved from https://www.audiologyonline.com/articles/20q-today-s-use-14101.
Mueller, H. G. (2015). 20Q: Today’s use of validated prescriptive methods for fitting hearing aids - What would Denis say? Audiology Online. Retrieved from https://www.audiologyonline.com/articles/20q-today-s-use-14101.×
Mueller, H. G. (2001). The research of Denis Byrne at NAL: Implications for clinicians today. Audiology Online. Retrieved from https://www.audiologyonline.com/articles/research-denis-byrne-at-nal-1200.
Mueller, H. G. (2001). The research of Denis Byrne at NAL: Implications for clinicians today. Audiology Online. Retrieved from https://www.audiologyonline.com/articles/research-denis-byrne-at-nal-1200.×
Mueller, H. G. (2001). Probe microphone measurements: 20 years of progress. Trends in Amplification, 5(2), 35–68. [Article] [PubMed]
Mueller, H. G. (2001). Probe microphone measurements: 20 years of progress. Trends in Amplification, 5(2), 35–68. [Article] [PubMed]×
Mueller, H. G. (1995). Probe-microphone measurements: Unplugged. Hearing Journal, 48(1), 10–12, 34–36. [Article]
Mueller, H. G. (1995). Probe-microphone measurements: Unplugged. Hearing Journal, 48(1), 10–12, 34–36. [Article] ×
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January 2018
Volume 23, Issue 1