Hearing aids have been helping with hearing loss for over a century. The development of hearing aids has come a long way from the first attempts at amplification to the modern-day devices that we see today. Early designs were large and clunky, and the technology was rudimentary as seen in the ear trumpet. However, advancements in technology have made hearing aids smaller, more discreet, and more effective. The evolution of hearing aid technology has allowed for a greater level of personalisation, and now, modern designs are tailored to each individual’s specific hearing needs. This essay will explore the history of hearing aid development and how hearing aids have changed from early designs to modern designs as well as addressing the main companies of today.
The History Of Hearing Aids: The Ear Trumpet
The ear trumpet was first referenced in 1634 in Recreations Mathematique, a book by mathematician Jean Leurechon and later in 1650 by Athanasius Kircher. The ear trumpet was made of natural materials such as sheet metal, silver, wood, snail shells and animal horns. They worked by funnelling sound waves from the surrounding into the ear; concentrating sound waves into the ear means a larger impact on the eardrum thus a louder sound is perceived.
Many different renditions of the era trumpet were made in the 18th and 19th century as the primary solution to hearing loss. Bespoke trumpets were made for certain individuals in the 18th century my instrument makers. The most notable company that mass made ear trumpets was started by Frederick C. Rein, in London in the 1800s. Along with trumpets, speaking tubes were used as a collective, as someone could speak directly into the speaking tube and therefore be heard better. The initial Rein trumpets were portable, however often large, and bulky, hence inconvenient and needed some kind of support. Over the course of the 19th century, there was a push for smaller trumpets, leading to the handheld trumpet and by the end of the 1800s, concealment of the hearing aid became more popular. A variety of forms of acoustic headband that had smaller trumpets on both sides were made with the main purpose of hiding the wearers disability. They could be worn over the head and made invisible by covering with hair or headgear.
The earliest know hearing aid is the ear trumpet, a conical shaped device that fits into the ear and funnels sound in.
The History Of Hearing Aids: The First Electrical Hearing Aid
The use of electricity allowed for major advances in the world of hearing aids. The invention of the telephone showed that the frequency, loudness, and distortion of sound could be changed, and these features of the telephone were thereafter transferred to make the first electrical hearing aids. The Akoulallion was invented by Miller Reese Hutchinson in 1898, however was very large and not easily portable. A second aid, by the name of Akouphone was made, which consisted of a piece that goes into the ear and a rubber box to contain the battery pack and other components. Both hearing aids were extremely expensive. Hutchinson made a third, more practical version, this time incorporating carbon technology. A carbon transmitter was embedded into the hearing aid which allowed for an amplification of sound by 15Dbs. The drawbacks of the carbon transmitter are that it produced scratchy noises and limited frequency range.
The History Of Hearing Aids: Vacuum Tube Technology
In 1921, the first commercial vacuum tube hearing aid was made called the Vactuphone, based on patents by Hanson. A vacuum tube is a clear glass tube that has a filament and a plate in it. A current is passed through a wire and the wire is heated so that electrons get agitated and pass into the space in the tube. The electrons flow to a plate with a positive charge and the current is reproduced. The name vacuum tube simply comes from the fact that the tube is a vacuum with no air in it so there are no particles to obstruct the electrons. A vacuum tube controls the flow of electricity better than a carbon transmitter and is able to amplify sound to 70 decibels. Vacuum tubes were very impractical as they needed large amounts of electricity and two batteries were needed, one for the filament and one for the plate. The size of the batteries meant the hearing aids had to come in a box that need to be place on a table. By the 1940s, Raytheon created sub miniature vacuum tubes that were about an inch small. This mean the new hearing aids using these vacuum tubes were wearable, despite still having two batteries.
The History Of Hearing Aids: Transistors
Bell telephone Laboratories invented the first transistor in 1948 which greatly impacted the size of a hearing aids. Transistors can start and stop the flow of a current and also control the volume of a current, making it possible to have multiple settings in one device. They use of transistors eliminated the need of two batteries and required a smaller power supply. This allowed hearing aids to vastly decrease in size where they could be fitted into glasses or pockets and ultimately led to the creating of the first in ear hearing aid in 1950 by the company Orion.
The History Of Hearing Aids: Digital Hearing Aids
Microprocessors were made in the 1970s and incorporated into digital hearing aids. The processor reads the microphones digital message end customises what is amplified to the receiver. Edgar Villchur developed analogue amplitude compression device that enabled the audio signal to be separated into frequency bands. These frequency bands were able to adjust the analogue sound so that loud sounds could be less amplified and weak sounds could become more amplified. Bothe the microprocessor and the compression device miniaturised hearing aids. The first fully digital hearing aid came out in 1987.
The History Of Hearing Aids: 21st Century Hearing Aids
Modern hearing aids work by picking up sound waves through a microphone, which then converts the sound waves into digital signals that are processed by a computer chip. The computer chip then amplifies the signals according to the user's specific hearing needs, and the amplified signals are sent to a tiny speaker that delivers the sound directly into the ear canal. Hearing aids have many new features that consist of:
AI can enable hearing aids to learn from the user's listening habits and preferences and automatically adjust the settings accordingly
Health tracking can be used were steps, heart rate and sleep are all sensed by the hearing aid and any sudden change in hearing can alert their healthcare provider.
Apps on the hearing aid users’ phone can be used to make adjustments to volume and frequency and check battery levels.
Bluetooth allows the hearing aid to connect with the phone or other devices so you can hear directly into your hearing aids.
Rechargeable batteries so batteries do not have to be replaced.
Waterproof or water-resistant hearing aids mean hearing aids are less prone to damage when coming into contact with water.
Two-way audio means you can also use your hearing aid as a microphone when making calls.
Noise reduction helps reduce specific noises such as loud noises, high or low frequency noises, or sounds such as the wind.
Directional microphones allow the hearing aid to focus on a specific direction, which can help in noisy atmospheres.
Telecoil are wireless features that allow you to pick up electromagnetic signals from compatible telephones or looped rooms. This is used in public performances and exhibits or in places of worship.
FM compatibility in hearing aids allows them to connect to FM systems commonly used in educational and public settings, providing improved sound quality.
The history of hearing aids: The Main Hearing Aid Companies of Today
Oticon
Oticon is a Danish hearing aid manufacturer that was founded in 1904 by Hans Demant. The company produced the first Danish made licensed hearing aid called the acousticus in the 1940s. The company went global in the 1960s and later in 1977 Oticon introduces the first ultra-discreet in-the-ear hearing device. They are known tobe world's second largest manufacturer of hearing devices. They are also the first hearing aid to connect to the internet.
GN ReSound
ReSound is a Danish hearing aid manufacturer that was founded in 1943 by Gerd Rosenstand. In the 1992, ReSound introduced the first hearing aid with a digital microprocessor. Throughout the following decades, ReSound continued to develop new hearing aid technologies, including the introduction of the first open-fit hearing aid in the 1990s and the first Made for iPhone hearing aid in 2014, where the hearing aids connects directly to the phone. ReSound also invented wide dynamic range compression technology which improves processing, and digital feedback suppression which reduces feedback in hearing aids.
Phonak
Phonak is a Swiss hearing aid manufacturer that was founded in 1947 by a group of French-Belgian investors. In 2003, they launched SmartLink the first hearing aid to facilitate the direct wireless use of Bluetooth mobile phones for hearing aids. Phonak launches the global hear the world campaign to educate the public about the consequences of hearing loss. They have introduced products like 2011s Phonak Lyric, a completely invisible hearing aid that can be worn continuously for months at a time and one of their latest hearing aids, Phonak's Paradise. Their collection of hearing aids includes Bluetooth, rechargeability, Precise calibration to an individual’s ear anatomy, or made of titanium to be strong and discreet.
Sivantos/Signia
Signia was founded in 1878 in Berlin, Germany as Siemens & Halske, producing a variety of electrical products, including hearing aids. In 1959, it introduced the first behind-the-ear (BTE) hearing aid, a significant development for comfort and discretion. In 2015, Siemens AG created a new entity, Sivantos Group, focused solely on hearing aids, with Signia as one of its primary brands. In 2014, they introduce the first wireless system connecting hearing aids in both ears together. In 2018, Sivantos Group merged with Widex to form WS Audiology, with Signia as a leading brand.
Widex
Widex was founded in 1956 by Christian Tøpholm and Erik Westermann, who previously worked at Oticon. The company released its first hearing aid, the Widex 561, in 1956, a pocket model hearing aid. Widex is the only CO2 neutral hearing aid manufacturer and has a reputation for ethical standards and corporate social responsibility. Their latest technology, Widex Moments, is a hearing aid that focuses on offering natural sound. After launching Widex Moments, Widex have repositioned themselves to become the only premium plus hearing aid manufacturer in the hearing aid industry.
Starkey
Starkey was founded in 1967 by William or Bill Austin. Bill initially started with an earmould lab and then progressed into manufacturing hearing aids. They have supplied hearing aids to some big names such as Ronald Reagan and Nelson Mandela. They are also well known for the Starkey Hearing Foundation, where the aim to create sustainable community based hearing healthcare. The UK Starkey headquarters is based in Manchester.
How hearing aids work is unique to you as there is no one size fits all.
Take Away Message
Hearing aids have come a long way since the first trumpet horn used to amplify sound. Today, hearing aids are powerful, rechargeable and full of advanced technology. Would you like to learn more about how todays technology can help you?
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