A Critical Appraisal of Nonconformity of New Hearing Aids with American National Standards Institute Standards

Some studies have found an alarming rate of hearing aids' nonconformity with American National Standards Institute standards, but research in this area is limited. This study reports a comprehensive assessment of the compliance rate of hearing aids of various brands and styles. The Audioscan Verifit-1 analyzer was used to examine the compliance of 62 new hearing aids with the S3.22-2014 standard of the American National Standards Institute. Audioscan Verifit-2 and Aurical test systems were also used to determine the potential influence of hearing aid test systems on the compliance rate. With the Verifit-1 test system, most hearing aids (96.8%) were found to be out of specification for the equivalent input noise measure. Compared to equivalent input noise, the compliance rates for output sound pressure level, high-frequency average at 50 dB, and total harmonic distortion were higher and did not differ between brands and styles. The type of analyzer had a considerable impact on the measured equivalent input noise compliance rate: Compared to the Verifit-1, the Verifit-2 and Aurical test systems indicated a higher compliance rate (> 90% versus similar to 5%). However, there were no differences in compliance rates across the analyzers for the rest of the tests. This study reveals that hearing aids mostly comply with the standard. There is a need to establish clinically reproducible and easily accessible testing protocols for the quality control of hearing aids at various stages of use.