Recent PSAP and OTC Studies Warrant Cautious Interpretation

February 16, 2017

With mounting anxiety over direct-to-consumer Personal Sound Amplification Products (PSAP) quality and availability, a few studies, published mainly in the non-refereed journals and online, have systematically evaluated their electroacoustic characteristics relative to hearing aids. The growing list of published studies comparing PSAP performance to that of modern hearing aids includes work from Northwestern University, Johns Hopkins School of Medicine and the University of Memphis.  

Confined to laboratory analysis, these studies suggest that a few, out of the dozens of PSAPs currently on the market, perform similar to hearing aids.


Exploring PSAPs vs. Hearing Aids

Tom Tedeschi, AuD


By adding a real world component, one recent study took a different approach to the PSAP versus hearing aid conundrum. Published on-line in late December by Hearing Review, Tedeschi and Kihm  explored the consumer’s journey when purchasing and using devices in an over-the-counter (OTC) environment.  

The main goal of this study, according to the authors, was to mimic the consumer’s ability to purchase an OTC product and compare their satisfaction to the traditional provider-driven service model.

Jan Kihm, MS

Tom Tedeschi, AuD, Vice President of Training & Development for Amplifon, Plymouth, MN and Jan Kihm, MS of AZ Marketing Research (an independent research firm that also conducted the industry-sponsored MarketTrak 9 study) in St. Paul, MN conducted this study, which was comprised of two phases. Over a 12-week time window, divided into two 6-week phases, their study compared a group of consumers’ experience with over-the-counter (OTC) products (Phase 1) to the traditional service delivery model (Phase 2) in which a professional directs the care.  


The aim of their study was to address these four broad questions:

  1. How well can individuals identify red flag conditions and classify their own hearing loss?
  2. How well can individuals self-select a hearing device for their needs without the guidance of a professional?
  3. How effective and satisfying is an OTC approach for individuals in need?
  4. How does an OTC experience compare to the traditional process of getting hearing aids from a professional?


Given the wide ranging scope of this study, there is much to unpack; thus clinicians are encouraged to read the entire article posted at the Hearing Review website, but here are some highlights: Twenty-nine adults were medically cleared to participate in the study. Although it appears none of the study participants were directly asked to self-identify a possible red flag condition, four individuals were referred to a physician for a possible medical condition and one was excluded from the study because of an outer ear infection based on a preliminary screening.

Hearing thresholds, which also were obtained prior to Phase 1 of the study, were compared to the participant’s self-reported hearing loss. All 29 participants reported hearing loss of mild or moderate degree.  The hearing test revealed that three participants had normal hearing, while 11 of them had a hearing loss more severe than they self-reported and 15 participants were able to correctly self-report the degree of their hearing loss, within at least the mild-to-moderate range. On the surface, these findings are not surprising, since several previous studies indicate that most individuals cannot correctly self-identify the magnitude of their hearing loss.

The second part of this study, which addressed questions 3 and 4 above, compared one type of direct-to-consumer model to the traditional provider-driven model. Twenty-nine eligible study participants completed Phase 1 of the pilot by using a self-selected PSAP or ready-to-wear hearing aid for six weeks.


According to the study, “at the conclusion of Phase 1, the 6-week survey revealed that 90% of the participants felt that having some assistance from a hearing healthcare professional would have been at least somewhat useful when getting used to the device.”


At the end of their six week trial with the OTC product/process “about half” felt that the OTC device helped some or all of the time, and they would recommend one to a friend who had a hearing problem, while another one-quarter of the group stopped using PSAPs entirely during Phase 1.

As Kihm said, “We know that Baby-boomers who are beginning to enter the market for hearing services, tend to want to be involved in their choices, but that things often look simpler than they are from the outside, when it comes to complex issues such as hearing loss. Our study provides insights on the customer experience with respect to over-the-counter model compared to the provider-driven model.”  


psap otc hearing aids

Personal Sound Amplification Products (PSAPs) and OTC hearing aids come in a variety of shapes and sizes


Phase 2 of the study, which involved direct care with a hearing care professional, was completed by 18 of the 26 participants with some level of loss who completed the first phase of the study. Although the details of the participants’ interaction with the professional were not disclosed in the article, each participant had their level of usage, expectations and satisfaction measured twice:  at 3-weeks and 6-weeks post intervention. Results indicated 83% were satisfied with the provider-driven fit, compared to 48% who were satisfied with the OTC fitting.  The article did not report if these differences in outcome between the two phases were of statistical or practical significance.

Tedeschi shared that “the study provides evidence that the professional is needed to optimize satisfaction.” He went on to say, “they have received a lot of positive feedback from others in the industry about their study.” Tesdeschi and Kihm stressed that this was a pilot study and expanded, follow-up studies are being planned.


Doubts on Interpretation of Study


Some, including research audiologists, like Catherine Palmer, PhD at the University of Pittsburgh Medical Center expressed skepticism about the interpretation of the evidence provided in this recent comparative study. “As an audiologist, these findings sum up what we (audiologists) bring to the table – customization – whether we are customizing the physical fit or customizing the acoustic fit.  That is what (consumers) are paying for when they see us.  So, the data from this study are consistent with what you would expect from this OTC model,” Palmer shared via e-mail.  


According to Palmer, the second part of the Tedeschi & Kihm study, where the OTC model was compared to the provider-driven model, “creates a straw-man that is easy to pull apart.”  Palmer elaborated, “There is literally no way to interpret the second part of the study because everyone had gone through the non-customized phase first.  One would expect a customized experience to be preferred, especially in close contrast.  In addition, there is every reason to believe that participants will want to please the hearing health care provider working with them.”


Lindsey Jorgensen, PhD, AuD

Lindsey Jorgensen, PhD, AuD an assistant professor at the University of South Dakota also questioned the study design and interpretation of the findings by the authors, “This article poses some interesting findings relevant for discussion. The article does have foundational interest, but the pointed and firm conclusions reached by the authors should be considered carefully. The study was not peer-reviewed and the research design was not thoroughly explained, and therefore, the conclusions expressed by the authors should be cited with caution.  Audiologists and consumers should be aware of the design limitations, relevance and outcomes when considering the study findings for clinical application.”

Another researcher was equally skeptical of any industry-sponsored study and emphasized the need to interpret any study, especially those appearing in trade publications, with great caution.  Vinaya Manchaiah, PhD, Jo Mayo Endowed Professor at Lamar University, Beaumont, Texas said, “Studies conducted by the industry (i.e., published as white papers) and also industry funded external research are very useful to produce knowledge through exploratory research. However, industry funding is reported to have a high risk of bias in terms of study design, analysis and reporting. Hence, it is important to have studies that are independent with limited or no conflict of interest in order for us to have full faith in a study.”


Hearing Professionals: Must be Responsible Consumers of Research


The presence of industry-sponsored research in trade journals and posted on-line can provide valuable clinical insights and have some advantages: They can be completed relatively quickly. When properly designed that can address emergent clinical questions, and they don’t suffer from the 12 to 24 month lag between study completion and publication that often plague peer reviewed studies.

However, relying on their findings to make important clinical decisions underscores the need for audiologists, hearing aid dispensers and other industry professionals to be responsible consumers of research.  In a world flooded with information, working knowledge of funding source, study design, statistical analysis and, finally, how to apply a study’s findings to the population being served are enduring skills that benefit professionals and their patients.  


*featured image courtesy SoundWorldSolutions

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