ASA/ANSI S3.46-2013 (R2023): Hearing Aids
Before modern hearing aids, people in the 13th century with hearing loss were using hollowed out horns of animals, such as cows and rams. It was not until the 18th century that a bulky, funnel-shaped, and collapsible ear trumpet was invented to treat hearing loss. It did not amplify sound but worked by collecting sound and funneling it through a narrow tube into the ear. Hence, for centuries people have suffered hearing loss. ASA/ANSI S3.46-2013 (R2023): Methods Of Measurement Of Real-Ear Performance Characteristics Of Hearing Aids provides specifications for the terminology for procedures and equipment, measurement methods and reporting requirements, and key equipment parameters and acceptable tolerances for hearing aids.
The First Hearing Aid
Alexander Graham Bell’s 1876 invention of the telephone, which included technology that could control the loudness, frequency, and distortion of sounds, spearheaded the invention of the first hearing aid. The first electric hearing aid, the Akouphone, was invented in 1898 by Miller Reese Hutchison. His design used an electric current to amplify weak signals.
Through the use of the carbon transmitter, an electric current could take a weak signal and turn it into a strong signal. This device consisted of a separate microphone, amplifier, headphones, and battery (which did not last very long). It, however, was cumbersome, clunky, not very portable, and difficult to use. Despite that, the Akouphone was an incredible success, praised as a “miracle” by American press. Further, Queen Alexandra of Denmark was so happy with the results that Hutchinson invented that she invited him to her husband’s coronation ceremony.
While early inventions like Hutchison’s Akouphone marked the beginning of hearing aid technology, today standards such as ASA/ANSI S3.46-2013 (R2023) provide precise methods for measuring real-ear performance, assuring modern hearing aids deliver accurate amplification and sound quality.
What Is ASA/ANSI S3.46-2013 (R2023)?
ASA/ANSI S3.46-2013 (R2023) covers the terminology, procedures and essential equipment characteristics for the measurement of the acoustic output and acoustic gain of hearing aids, coupled to human ears, in a variety of acoustic environments and for the measurement of certain acoustic properties of the ear related to the application of hearing aids. These measurements can be divided into two classes:
- Direct measures (previously called in situ measurements) of sound pressure level (SPL): report SPL developed in an ear canal, with or without a hearing aid in place and are expressed as dB gain relative to the SPL at a field reference point.
- Insertion measurements: report ear canal SPL with a hearing aid in place relative to the ear canal SPL without the hearing aid.
Behavioral measures of real-ear hearing aid performance, such as functional gain, are excluded from this standard.
Applications of ASA/ANSI S3.46-2013 (R2023) for Hearing Aid Performance Measurement
Applications of this standard include the selection, ordering and fitting of hearing aids; the collection and reporting of research data; and the selection of equipment used for the measurement of real-ear performance characteristics of hearing aids. Unless otherwise stated, the measurements and requirements in ASA/ANSI S3.46-2013 (R2023) apply to a minimum frequency range of 200 to 6000 Hz. This standard aims to assist those making or interpreting the results of real-ear performance measurements of hearing aids by promoting consistency in terminology, procedures and equipment specification.
Commercially Manufactured Hearing Aids
In the 19th century, the potential business from hearing aids received more attention from manufacturing companies that specialize in mass production. Engineers wanted to make more advancements with commercially manufacturing the device. The first commercially manufactured hearing aids were produced in 1913.
In the 1920s vacuum-tube hearing aids named the Vactuphone were produced by naval engineer Earl Hanson. These tubes were able to turn speech into electric signals and then the signal itself was amplified through the receiver. The idea of miniaturization was ushered in with other technological advances spurred by WWII. Competition to develop the best miniaturization techniques aided development, and hearing aid devices became smaller and smaller throughout the 1930s, were sold as wearable from 1936, and quickly gained popularity amongst the public. At this time, the amplifier and batteries needed to be worn around the user’s neck and the microphone was hand-held (with its size proportional to the user’s level of hearing loss).
The transistor was invented in 1948, and transistors were able to replace the vacuum tubes in previous models of hearing aids and were smaller, needed less battery power, and had less distortion and heat. In the 1970s, the microprocessor, advancing miniaturization of the hearing aid, and the multi-channel amplitude compression were created. From then the use of digital technology ushered the evolvement of hearing aids. The 1980s saw the creation of high-speed processors, digital chips, and microcomputers. These enabled fast processing, but were too large and consumed too much power to be used in wearable hearing aids.
The 1990s saw the appearance of the first all-digital hearing aid, and the 2010s brought the idea of Bluetooth enabled devices into the mix. These modern devices using Bluetooth connection and rechargeable batteries, offer convenience to the consumers. Along with these advances, the emergence of new options such as hearing amplifiers and PSAPs (Personal Sound Amplification Products) offer the consumer a wider range of hearing device options with different capacities.
Where to Find ASA/ANSI S3.46-2013 (R2023)
ASA/ANSI S3.46-2013 (R2023) is developed by the Acoustical Society of America (ASA).
Please direct any technical questions relating to this American National Standard to the developer. You can find the contact information for all standard developing organizations (SDOs) here: Who to Contact for Standards Related Questions.
ASA/ANSI S3.46-2013 (R2023): Methods Of Measurement Of Real-Ear Performance Characteristics Of Hearing Aids is available on the ANSI Webstore.
