The evolution of hearing aids: from ear trumpets to digital

In this day and age, we take for granted the miraculously crafted hearing aids that allow millions of people to fully experience the world around them rather than living a life hindered by silence or hearing loss.

Hearing-aid history is convoluted but is an example of how technology evolves over time as more discoveries are made and lessons are learned. The first hearing aids appeared as far back as the 17th century.

In ancient civilizations, people with hearing impairments sought various methods to improve their auditory experience. One notable solution was the use of ear trumpets, which were simple, funnel-shaped devices designed to amplify sound. These early hearing aids were primarily made from materials such as animal horns, seashells, or metal.

Ear trumpets were widely used across different ancient cultures, including the Egyptians, Greeks, and Romans. These devices worked by capturing sound waves and directing them into the ear canal, thus enhancing the perception of sound for individuals with hearing loss.

While the effectiveness of ear trumpets varied depending on their design and construction, they undoubtedly provided some level of amplification. Historical records suggest that ear trumpets were particularly effective in improving hearing for individuals with mild to moderate hearing loss. However, their effectiveness diminished for those with severe or profound hearing impairments.

In 1898, Miller Reese Hutchison, an American engineer, invented the first electric hearing aid, known as the Akouphone. Hutchinson was inspired by the great inventor Alexander Graham Bell and his invention, the telephone – man’s first foray into controlling sound transmission, volume and frequency.

This groundbreaking device utilized carbon transmitters to convert sound waves into electrical signals, which were then amplified and delivered to the user's ear through a receiver.

The Akouphone revolutionized hearing assistance by providing a more efficient and adjustable amplification system. It allowed individuals with hearing loss to customize the amplification levels according to their specific needs, significantly improving their ability to communicate and engage with the world around them.

Carbon hearing aids were more compact and lightweight, making them more practical for everyday use. This innovation allowed individuals with hearing loss to experience enhanced sound amplification without the burden of carrying bulky devices.

Over the next several decades, miniaturization and practicality came to the forefront of hearing aid innovation.

The first wearable hearing aid was created by Aurex Corp in 1938. The device consisted of an amplifier-receiver which was clipped to the user’s clothes with a thin wire connected to an earpiece. A battery pack, which powered the device, was also strapped to the user’s clothes.

World War II led to further advancements in the field of audiology in response to the requirements of war-affected veterans. The war itself also pushed the advancement of technology, with miniaturized electronics becoming crucial to the war effort.

The advent of digital signal processing (DSP) in the late 20th century brought about a new era of hearing aid technology. Digital hearing aids replaced analog circuitry with microprocessors, allowing for more precise sound processing and customization.

DSP technology revolutionized sound quality in hearing aids. By converting sound into digital signals, the microprocessors could analyze and manipulate the audio data with greater accuracy. This enabled digital hearing aids to reduce background noise, enhance speech intelligibility, and provide a more natural listening experience.

Furthermore, digital signal processing allowed for advanced signal shaping and frequency-specific amplification. This meant that hearing aids could be tailored to an individual's specific hearing needs, amplifying certain frequencies more than others to compensate for their unique hearing loss profile. The customization options provided by digital technology greatly improved the effectiveness and satisfaction of hearing aid users.

The 1970s would prove to be the next great leap forward for hearing aids. Scientists had explored the idea of using computers to aid those with hearing loss. However, practicality and implementation simply didn’t match up due to the sheer size of computers at that time.

Along came micro-processors, which would allow miniaturization of the hearing aid to be taken to the next level.

In 1982 at the City University of New York, the first hearing aid to use microcomputers to process signals in real time was developed. It used FM technology to transmit signals to be processed by the microcomputer. Then in 1989, the first iteration of the behind the ear (BTE) hearing aid was produced. The humble hearing aid had come along way from holding a horn to one’s ear to now being an almost invisible device driven by wonders of technology.

In 1995, Oticon developed the world’s first digital hearing device, the JUMP-1. It could be reprogrammed, and attempted to use different signal-processing systems over extended periods of time to allow normal daily use. Oticon actually shipped the device to multiple audiology research development centres worldwide to share its technology and allow for further developments in hearing aid technology.

The following year, Widex introduced the first fully commercialized hearing aid. The 'Senso' had fully-automatic digital adjustment, with the user needing only to choose whether to activate the microphone or telecoil input. Everything else was adjusted automatically, meaning unwanted noise could be efficiently filtered out. The device even had its own built-in audiometer.

From 1996 to today, the technological advancement of hearing aids has continued to accelerate far beyond what those who had originally created the devices in the 17th century could ever imagine.

Modern-day hearing aids continue to shrink in size, are now suitable for all ages (including babies), can be connected to a range of other electronic devices using and, as recently as 2023, hearing aids may now be equipped with health monitoring artificial intelligence, which can even detect when elderly/frail users have fallen over.

Advancements in hearing aid design have revolutionized their size and appearance, making them more discreet and inconspicuous than ever before. Miniaturization has been a key focus in the industry, driven by the demand for less visible and more comfortable hearing aids.

Companies like Widex and Oticon have introduced receiver-in-canal (RIC) hearing aids, which are smaller and sit behind the ear, with a thin wire connecting to the receiver in the ear canal. This design allows for improved sound quality, reduced occlusion effect, and a more natural listening experience. Additionally, the use of nanotechnology has enabled the development of even smaller hearing aids that are virtually invisible when worn.

The integration of hearing aids with wearable technology has opened up new possibilities for enhanced functionality and improved user experience. With the rise of smart devices and the Internet of Things (IoT), hearing aids can now connect wirelessly to smartphones, tablets, and other wearable devices.

This connectivity enables users to stream audio directly to their hearing aids, make phone calls, listen to music, and watch videos in a seamless experience. Furthermore, the integration with wearable devices allows for personalized control and customization of hearing aid settings through mobile applications. Users can adjust volume, change programs, and even geotag-specific settings for different environments.