Measures of hearing aid quality should encompass a number of domains including sound quality, consistency of the audio output, durability, comfort for the user, moisture and dust resistance, and usability and effectiveness of the software programming interface. However, there is currently no single set of standards that allow for the differentiation between quality and lower or non-quality products.
Quality of hearing aids affects the user experience; poor sound quality, discomfort, or unreliability can lead to low usage rates or discontinuation. This limits the benefit that the user can derive from the hearing aids and makes it less likely that they will persevere until they find a quality product that works well. In addition, a poorer quality hearing aid can over-amplify some sounds, contributing to hearing damage. Lastly, while many products that are considered by experts as high quality meet moisture and dust resistant standards (such as I.P.6742,43), they are still not well-suited for L.M.I.C. climates, which tend to be harsher than H.I.C. climates, and can often breakdown or get damaged quickly if not well protected.
The W.H.O. P.P.P. provides some guidance on aspects of quality but is not designed to be a rigorous quality standard. Many products match the W.H.O. P.P.P. on paper, but in practice have poor sound quality, are not durable, or are difficult to program by the provider. Unfortunately, there are no existing or planned standards for hearing aids that provide an objective measure of quality to inform procurement for low-resource settings.44 According to experts, the U.S. F.D.A. and C.E. marks are not able to differentiate quality from non-quality products on the measure of hearing quality outlined above, and there is no globally recognised quality-testing programme. The F.D.A. requires certification of gains and output of hearing aids through a third party agency to ensure they match specifications but that is not a certification of quality.45 While W.H.O.'s forthcoming Assistive Product Specifications (A.P.S.) will providing further clarity to procurers, they will not serve as an established quality standard.
In the absence of objective quality standards, private providers are loyal to certain manufacturers where they and their clients have had positive experiences with specific products, typically one of the leading global manufacturers. To maintain brand reputation, these manufacturers rigorously enforce internal quality standards. In seeking lower-cost alternatives, audiologists may conduct a “field test” of products, by having users try them for a certain period and then reporting their experiences with the products. The results of these tests are rarely published.46 This leaves procurers without guidance on which hearing aids are of high quality and they often award contracts for hearing aids to the lowest bidder.