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OTC personal amplifier research was flawed – SAAA

Natalie Buttress, co-chairperson of the Ethics and Standards Committee of the SA Association of Audiologists, writes that a recent study on the performance of over-the-counter (OTC) personal amplifiers was architecturally flawed and over-confident in the conclusions drawn.

She writes:

Re: Medical Brief 163 13 July 2017: Some hearing assistance devices perform as well as hearing aids

We thank you for your contribution to the medical profession via the distribution of valid and interesting articles for professionals. The SAAA is in favour of sharing valid and scientific evidence with members of our profession, the broader medical profession, and members of the public. However, we are concerned about articles which may contain misleading information about the effect and role that our profession, and chosen professional tools play, in supporting hearing function and quality of life of individuals with hearing loss.

We would like to highlight certain pertinent points in the research study and published article.
The article in your email states that:
1. in the study, over-the-counter or Personal Amplifiers (PSAPs) “performed almost as well as a conventional hearing aids”.
2. It also mentioned that the study was performed in “our controlled environment” and that “We don’t yet know if people can achieve these results on their own with these devices”.
3. Finally, the article also noted that electroacoustic measurements were made and that “devices were fit and adjusted by audiologists to achieve the optimal hearing outcome.”
Our committee has reviewed the article and also the quoted research, and we point out that the controlled conditions of the study (being in a soundproof booth with certain restricted sound sources for noise and signal) are wholly unlike the real-world condition.

Many of the features of sophisticated technologies that are referred to as more expensive ‘conventional hearing aids’ are geared specifically around the management of real-world conditions. People with hearing loss do not exist in a controlled environment.

Quiet, controlled environments require amplification for audibility, but seldom create a challenge for hearing if speech is sufficiently loud. Most individuals with hearing loss will experience their greatest difficulty in challenging environments. It is in these environments that features which allow directional hearing and noise reduction, are necessary for quality of sound, and quality of life.

In addition, the original study’s architecture is flawed, as it clearly states that audiologists, using sophisticated electroacoustic measures, SET these over-the-counter devices for the purpose of the study. The nature of the sale of OTC devices presupposes that the device is preset and that the wearer simply uses it as a ‘plug-and-play’ device to assist with hearing loss.

The construct that was tested, therefore, was a professional audiologist’s ability to make an OTC hearing amplifier behave similarly to a conventional hearing aid in a soundproof booth with controlled sound signals, rather than a true comparison of OTC technology against sophisticated, well-researched, professionally fitted and adjusted technology, for hearing loss.

While the authors of the study acknowledge the potential shortfall in generalisability of the sample and results, the heading of the article (and indeed, your lead in your email) imply a greater level of confidence. In addition, the nature of the article is severely misleading, implying that OTC technologies may have the performance to replace existing technology and proper professional assessment and fitting, at a much lower cost.

While OTC hearing devices may have a future in the lower cost management of hearing loss, hearing aid fittings are a legally limited role in South Africa, for good reason. Incorrectly fitted OTC devices have the potential to cause hearing loss, and self-treatment of hearing loss has the potential to prevent or delay the diagnosis of conditions that may become life-threatening.

Therefore, SAAA would appreciate it if you would publish our response. We think that the medical profession and the public would be better informed with the views that we have expressed here.

Thank you for your consideration.

Natalie Buttress
Co-Chairperson of the Ethics and Standards Committee
SA Association of Audiologists

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