OTC Hearing Aids and Objective Verification

John Pumford, AuD, is the Director of Audiology, Education and Clinical Research at Audioscan. Previously, Dr. Pumford held senior audiology, clinical research, and management positions for some of the industry’s leading hearing instrument companies. He has also held clinical audiology positions in hospital and private practice settings and worked as a research audiologist at the National Centre for Audiology at Western University (London, Canada) where he investigated compression processing, directional microphones and contributed to the development of the DSL version 5 prescriptive formula. Dr. Pumford has presented extensively internationally on hearing instrument technology and best-practice verification procedures and has authored numerous articles and book chapters on these topics.www.shutterstock.com. Over-the-counter hearing aids, OTCs, Audioscan, Perspectives With Dr. BeckDr. Beck: Hi, John. Thanks for your time today! Dr. Pumford: Hi, Doug. Thanks for inviting me! Dr. Beck: My pleasure! I know you were with Audioscan in the late 1990s and early 2000s as part of the team that developed and released the Verifit1 before spreading your wings for a while in other roles within the hearing industry. Now, after a multi-year break, you’re back at Audioscan for just about the last 10 years leading education and clinical research initiatives for the company. As such, I think you’ve done just about as many verification assessments and lectures as anyone else over the last 26 years and your expertise in this area is well-established! By way of disclosure, I should mention that you and I have presented many lectures, and have written articles, together over the years. Now, with all that as background, let’s jump in. I’d like to discuss how and why hearing care providers (HCPs) might choose to verify OTC hearing aid fittings. Dr. Pumford: Absolutely! Now that we’re about 1.5 years past the FDA’s final ruling on OTCs, I’ll bet many HCPs are thinking about this. Dr. Beck: I’d like to start by saying that each patient is unique, and each hearing aid is unique, and more importantly – each patient’s perception of sound is unique. That is, despite all the critically important objective data and outcomes-based evidence, what we each perceive is more than the stimuli. Perception depends on the knowledge, the emotional state, the psychological state as well as the hearing and listening ability (i.e., the internal state) of the observer (see Serences, UC San Diego). Dr. Pumford: I agree. We have a responsibility to objectively measure what we can, to give the patient a known and well-defined sound to begin with based on validated prescriptive methods and best practices to meet their anticipated requirements and outcomes. Dr. Beck: Of course we can look at the hearing aid ratings and specifications, and of course we can look at the patient’s audiogram and speech-in-noise assessment and more. But, in my opinion, the most important factors are how well the hearing aid is programmed, and is it meeting the needs, expectations, and outcomes that the patient seeks. Dr. Pumford: Absolutely. Those are the foundational issues for OTC and prescription hearing aids. Dr. Beck: How do you recommend verifying an OTC product? Dr. Pumford: Well, one thing to consider is that OTC products can be verified in the test box using clinical test systems to assure us that they meet the requirements of the final FDA ruling. This ruling laid out several technical requirements for this category of device, along with the hearing loss (mild to moderate) and age of the client (adult) these devices were intended for. On the technical side, the FDA ruling considered the methodology of the ANSI/CTA-2051 standard, and the ANSI s3.22-2014 standard. As such, there is guidance provided regarding how the device should be measured, which signals should be used, mathematical transforms, etc. Importantly the FDA provided pass/fail criteria on several electroacoustic measures with the aim of ensuring safety and effectiveness since these devices will likely be fitted without professional care. Readers interested in learning more about each of these aspects can refer to the following documents: https://www.federalregister.gov/documents/2022/08/17/2022-17230/medical-devices-ear-nose-and-throat-devices-establishing-over-the-counter-hearing-aids https://webstore.ansi.org/standards/ansi/cta20512017ansi https://webstore.ansi.org/standards/asa/ansiasas3222014 At Audioscan, we have recently released a dedicated test box test-suite that considers the FDA ruling and technical documents to provide an accurate and efficient way to assess the quality and safety of OTC devices. This test suite simplifies data gathering and interpretation and can allow those less familiar with EAA measures and the FDA criteria to run the test as a pass/fail indication for each measure is shown on the screen. However, an important caveat remains, each HCP, their colleagues, and assistants must adhere to their state laws and regulations regarding scope of practice. Dr. Beck: In general, while assessing test box measures, I look at the manufacturer’s specifications, I compare those to the specific hearing aid being tested. However, as there are hundreds of different OTCs, and we’re not likely to find the manufacture’s specifications for a given device, what are we looking for? Dr. Pumford: What we are looking for is to verify that the OTC device being tested is within the general safety and product quality guidelines for OTC products on the metrics of interest from the FDA ruling. These aspects include the max OSPL90, bandwidth, frequency response smoothness, total harmonic distortion, latency, and internal noise. So, for example, the Maximum OSPL-90 should not exceed 117 dB SPL for input compression devices, or not exceed 111 dB SPL if the OTC product does not have input compression. The THD at 500 Hz for outputs of 100 dB SPL should not exceed 5%; the latency should not exceed 15 msecs; internal noise should not exceed 32 dBA; and the bandwidth and consistency of the frequency response across the frequency spectrum also must be within the guidelines. Dr. Beck: When we’re verifying OTC products we’re looking for compliance more than a specific value? Dr. Pumford: In general, that’s right. We want to ensure the measures do not exceed the performance criteria specified by the FDA on the parameter in question. And regarding these parameters, arguably the only actual ‘patient safety’ factor is the Max OSPL-90 performance specification. As you recall Doug, there is no actual ‘full-on gain’ criteria or guidance in the final 2022 FDA rules. And so ultimately, the OSPL-90 is a very important measure as we want to make sure (as best we can) that OTC products are not going to cause additional hearing loss for the intended patient population of adults with mild to moderate hearing loss. Dr. Beck: And apparently the thought process was that gain doesn’t cause hearing loss, output causes hearing loss. And thankfully the FDA lowered the OSPL-90 to the levels noted above after much discussion and debate. Dr. Pumford: Yes, this is a more reasonable OSPL-90 than the higher numbers they started with. Nonetheless, it’s important to counsel patients (when possible) that long term exposure to 117 dB can cause hearing loss. Dr. Beck: Absolutely. In an analogous world, OSHA says listening to occupational noise at 90 dB for 8 hours is dangerous, and by the way, NIOSH uses even lower thresholds. OSHA reports as the loudness increases by 5 dB the -exposure time decreases by half. So when we examine dangerous industrial noise exposure time versus loudness, we get 95 dB for 4 hours, 100 dB for 2 hours, 105 dB for 1 hour, 110 dB for 30 mins, 115 dB for 15 minutes and 120 dB for 7.5 minutes. Extrapolating from these numbers indicates that about 12 minutes exposure to industrial noise at 117 dB can be dangerous and may cause additional hearing loss. It’s useful to re-visit these OSHA and NIOSH warnings now and then, and to recall that even hearing aid amplified sounds can cause damage! Dr. Pumford: I think what you are touching on reinforces the need for warnings and counseling about safe listening levels versus listening time for all our patients. To frame this in a larger context, all the numbers, criteria and specifications we’ve been talking about are limited to the specific product being tested. Importantly, none of the discussed performance specification measures tell us anything about the aided audibility provided by the product for the specific patient. To help with this, we offer an aided audibility screening tool as part of our OTC test suite. This test box feature allows clinicians to quickly see if the OTC device can provide ‘appropriate’ audibility for an adult with mild to moderate hearing loss by comparing simulated real-ear measurements to a range of NAL-NL2 or DSL5 targets for soft, average, and loud speech inputs. This information can be quite helpful as a learning and counseling tool to guide clinical decision-making. That said, we are still limited in patient specific information with the OTC model. Best Practices for the traditional prescription-based hearing aid workflow provides us with information about patients’ audiograms, listening and communication difficulties, speech-in-noise scores, and more. In contrast, with OTC patients, all we likely have is product information, and that might be thought of as pass/fail. Dr. Beck: And so the challenge is that although we can verify the pass/fail factors of the OTC product, as you’ve indicated above, without a comprehensive audiometric evaluation, we have no information about the patients’ ability to hear or listen. Dr. Pumford: Yes. That is a key point, and it gets back to your introductory note where you mentioned that the most important factors to keep in mind are: How is the hearing aid programmed? And does it meet the needs of the patient? And so in a pure OTC world without professional care, we just don’t know these answers. Dr. Beck: Once again, I find myself saying that all patients with concerns, problems, issues or worries about their hearing and listening ability—particularly people with speech-in-noise difficulty—should have a comprehensive audiometric evaluation. Screenings leave too many unanswered questions, and they often lead to a false sense of security. Specifically, a person can have normal thresholds and will pass a screening, yet 23-26 million Americans who pass a hearing screening can have very significant listening difficulties, most of which will be invisible on a simple screening. Dr. Pumford: Another issue we might mention is that the -better OTC products are actually pretty good, and most likely they will get better as time goes on. Many I’ve measured do well on meeting the new FDA ruling criteria and many patients appear to get appropriate benefit. That’s all good! However, patients should realize that the better OTC products often cost as much or more than a basic or mid-level prescription product. And the prescription product comes with, or comes after, a comprehensive audiometric evaluation, and includes loss, theft and damage warranties, and will be professionally programmed when dispensed. The product will probably last 5 to 7 years, and it can be reprogrammed as needed. Sometimes even for the shopper on a tight budget, the prescription hearing aids can be a better value. Dr. Beck: Thanks, John. I agree. For the shopper looking to spend $100-$300, the choices remain limited. Nobody knows how long those products might last. Now that OTC is here, I think most hearing care professionals are comfortable with the concept. Further, I think we only have a slight measure of the actual sales and impact of OTCs for the first 18 months. To my knowledge, there is no way to count the products and packages from retail pharmacies, big box or OTC sources delivered through the mail, UPS or Amazon from OTC providers and manufacturers at home, or off-shore. We have estimates from the largest prescription product providers, but I think it may be like an iceberg, we can see the tip (10%), but perhaps the bulk of it (90%) lies out of view? Dr. Pumford: Good points. I guess we’ll have increasingly better information as time goes on. We do know that traditional hearing aid sales have grown in the last year, and they don’t appear to be impacted by OTC. Dr. Beck: Right! And that’s great news. It could be that both markets (OTC and prescription) are developing and growing and neither significantly impacts the other. Maybe the OTC patient is functionally a different patient than the prescription patient and both markets will grow as the population ages. Nonetheless, John, thanks for your time and insight. I always learn something when I work with you! Dr. Pumford: Thanks, Doug. I always enjoy working with you, too!

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