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Digital Hearing Aids - The Future of Hearing!

Hearing loss isn't a new problem. It has been afflicting people for millennia.


Hearing loss has a significant impact on one's life. It impacts your social connections, emotional well-being, and even your professional life. Individuals with hearing loss were widely assumed to have a variety of other disabilities until the 16th century, which resulted in them being highly discriminated against. This fact was not disproved until a Spanish monk named Pedro Ponce taught a nobleman's deaf sons how to read, write, speak, and do the math.

They're often undetectable to the people with whom you're interacting. That wasn't always the case, though!


Background

Those with hearing loss have been utilizing hollowed-out horns of animals like cows and rams as primitive hearing devices since the 13th century. The better ear trumpet was not invented until the eighteenth century. Ear trumpets, which were funnel-shaped in design, were man's earliest attempt at designing a device to remedy the hearing loss. However, they did not magnify sound; instead, they collected it and funneled it into the ear through a tiny tube. These bulky ear trumpets and the resulting speaking tubes didn't operate very well.

Alessandro Volta, a researcher, implanted metal rods in his own ears and connected them to a 50-volt circuit in about 1790. This is the first time electricity has been used to hear.

Another attempt to excite the ear electrically was attempted around 1855. Other tests with electrical treatment for ear disorders were also conducted.


How does normal hearing work?

When sound enters the ear, it travels from the pinna (or auricle) into the ear canal and causes the eardrum (or tympanic membrane) to vibrate. The eardrum is placed before the middle ear, which amplifies the sound before delivering it to the inner ear.

The eardrum is connected to three tiny bones in the middle ear, which transmits vibrations to the fluid-filled region of the inner ear (called the cochlea). The vibrations create movement in the fluid-filled cochlea, which causes the inner ear's microscopic hairs to move. This triggers a chemical reaction that stimulates the hearing nerve, which then transmits the information to the brain, where it is recognized as sound.


First Hearing Implant

The Akouphone

In the nineteenth century, the first electrical hearing aids were introduced to the world. The telephone, which was invented in 1876, provided the required technology to manage sound loudness, frequency, and distortion.

Using this technique, Miller Reese Hutchison of Alabama created the first electric hearing aid in 1898. Hutchison's concept employed a carbon transmitter to amplify weak audio signals using electric currents, which was a big breakthrough for hearing aids.

His device was dubbed the "akouphone." The item cost US $400, which equates to US $13,236.67 in today’s time. It wasn't a solution that was easily transportable, however. Because the akouphone was so huge, it had to be placed on a table.


The Vactuphone (1920s to 1940s)

Earl C. Hanson, a navy engineer, developed a vacuum tube hearing aid in 1920. Sound amplification became much more efficient with this new type of hearing aid. Even people with severe forms of hearing loss may benefit from it.

The vactuphone technology converted voice into electrical signals using a telephone transmitter. As the signals progressed to the receiver, they became more amplified.

Despite the batteries being stored in a big compartment at the bottom of the box, the vactuphone was still quite enormous. It's light enough to fit in a small bag, weighing just over three kilogrammes. However, batteries were extremely costly in 1920. The vactuphone originally cost $135.00 and is now worth around $1,742.00.

The vacuum tube hearing aid became more popular during the next two decades, and its size gradually shrank.


Transistor Hearing Aids (1950s)

The invention of transistors in 1948 resulted in significant advancements in hearing aid technology. Transistors could now take the role of vacuum tubes, which had the drawback of becoming rather hot. Because these aids used less battery power, they shrank in size as well. They'd soon resemble the hearing aids we have today in appearance. They can also be worn behind the ear or within.

In 1951, mass production began in the United States. However, because the time to market was so short, transistor hearing heads were never thoroughly tested.

A Texan business developed a silicon transistor that was more effective and stable than its predecessor in 1954. Transistors could get moist and cause the hearing aid to failing after only a few weeks, as was later discovered. The problem was rectified by adding an extra layer of coating.

When Jack Kilby devised the integrated circuit, now known as the microchip, in 1958, the age of the transistor hearing aid came to an abrupt end. His invention would pave the way for today's hearing aid technology and completely change the business.


Digital Hearing Aids (1960s)

Hearing aids would get smaller and more powerful as the digital age progressed. From the 1960s forward, hybrid gadgets with analogue features became popular. Hearing aids became minicomputers only a decade later when the microprocessor was invented. Hearing aid technology would swiftly advance after that.


Former US President Ronald Reagan was photographed wearing his hearing aid in the office in 1983. Reagan claimed that the hearing aid assisted him in overcoming a problem with high-pitched sounds. According to the New York Times, his hearing loss supposedly began in the 1930s, when a pistol was shot quite close to his right ear. The president of the United States' public acknowledgement was a watershed moment for the hard of hearing community. It depicted a powerful international leader promoting hearing aid use. It would significantly eliminate the stigma attached to hearing aids. Digital hearing aids had never been seen before in the 1990s. Another US president quickly followed suit, publicly promoting the use of hearing aids and emphasizing the need for hearing examinations. As a music fan, Bill Clinton was well aware of the consequences of excessive volume listening. Long-term exposure, combined with natural decrease, necessitated the use of a hearing aid, which was practically imperceptible by 1997.


Digital technology swept the market with a vengeance. In the years that followed, personalization was at the forefront of technological breakthroughs.

Hearing implants became fully customizable to different types of hearing loss in the 2000s. Hearing aid users can now tailor their devices to their specific needs and preferences. Many hearing aid users reported a significant improvement in their experience as a result of this.

Bluetooth was first used in 2010, and you may now connect your hearing device directly to your television and smartphone if you so desire. Almost every aspect of your listening experience can now be personalized. The only limit appears to be the sky!


The Breakthrough

Researchers achieved a significant breakthrough when they discovered that electrical energy might be converted into sound before reaching the inner ear. Researchers discovered that applying a current near the ear could produce auditory sensations during the Depression years of the 1930s. The scientific community also gained a better understanding of how the cochlea functions.


The year 1957 brought the first stimulation of an acoustic nerve with an electrode by the scientists Djourno and Eyries.

The participant whose nerve was activated was able to hear background noise in that experiment.

In the 1960s, research accelerated dramatically. The electrical stimulation of the auditory nerve was still being studied. Researchers achieved a significant breakthrough when they discovered that particular auditory nerves must be activated by electrodes in the cochlea to replicate the sound.


In 1961, Dr William House implanted three patients. All three discovered that the implants could help them in some way. An array of electrodes was put in cochleas a few years later, from 1964 to 1966, with good results. Researchers learned more about electrode placement and the effects of that placement.

From the 1970s to the 1990s, implant technology advanced tremendously. In the 1970s, more patients were implanted, research proceeded, and a multichannel device was developed.


In 1984, the cochlear implant was no longer considered experimental and received FDA approval for adult implantation. Other advancements in speech processors and other implant technology were developed throughout the 1990s, particularly the shrinking of the speech processor so that it could be put into a BTE hearing aid-like device.


Working of Hearing Implant

A hearing implant offers a sense of hearing by bypassing the damaged hair cells in the cochlea and directly activating the auditory nerves with electrical signals, rather than just making sounds louder (as with a traditional hearing aid). A hearing implant has two primary parts: an external element that hooks over the ear or is worn off the ear (on the head) and an internal part that is surgically inserted. A strong magnet is used to connect the two components. Hearing implants come in a variety of shapes and sizes. The most important one for someone who has hearing loss is determined by the source and kind of hearing loss. Hearing implants are relevant in all circumstances when a person with a hearing loss would not benefit fully from the sound amplification of hearing aids or is unable to wear hearing aids for some reason.


Parts of a Hearing Implant

External

A microphone, a speech processor, and a transmitter make up the external component of a cochlear implant. On other models, the microphone and speech processor are housed in a compact unit that resembles a behind-the-ear hearing aid. Some are worn on the head, while others are worn on the body. They are normally connected to the transmitter by a short wire that runs through the device's inside. Acoustic sounds are picked up by the microphone and sent to the speech processor; before transmitting the signal to the transmitter, the processor analyses and digitizes it. The signals are subsequently coded and sent to the implanted receiver via magnetic coupling by the transmitter.


Internal

A receiver, which is situated under the skin on the temporal bone, and one or more electrode arrays make up the internal part of a cochlear implant. The transmitter sends out signals, which the receiver absorbs and turns into electrical pulses. It then sends the pulses to electrodes that have been implanted deep into the inner ear. The auditory nerve is stimulated directly throughout a part of the cochlea by these electrodes, and the brain interprets the signals as sound.


Patent Data Analysis

The US records the highest number of patents than any other country. It has always been at the forefront, and all the evolutionary changes in the hearing aid and implant domain have taken place in America, followed by Europe. Also, remarkable initiatives are being taken in Audiology that results in technological advancements more in the States than anywhere else. Europe, China and Japan are seen climbing the ladder with efforts being made in R&D and implementation of the same in bringing up new and innovative products. A lot of effort is also being put into bringing down the prices for everyone to afford hearing loss remedies.

If we see the patenting trend of the last 10 years, we would see rather slow growth in the area of hearing implant technology. But a slight spike could be seen when the number of patents reached 2280, but a fall followed, and the trend is still on the decline. This can be attributed to the fact that a lot of focus is on developing remedies for life-threatening diseases and ailments that are more complex and have a relatively larger impact on lives.

Medtronic combines technology with cutting-edge medical research to produce solutions that have never been seen before. Whether it's developing less invasive surgical procedures to reduce patient downtime or constructing the world's smallest pacemaker, their ability to change people's lives can be seen from the fact that they are the leaders having almost 2042 patents to their credit.


The most successful product of Medtronics is Alpha 2 MPO ePlusTM bone conduction hearing aid that uses Bone conduction hearing technology to maximise the body's natural capacity to transfer sound. It is suitable for patients with conductive hearing loss, mixed hearing loss, and single-sided sensorineural hearing loss.


Edwards Life sciences and Cochlear are too in the race as they provide solutions to hearing loss patients of all ages. The rest of the companies have still a long way to go. Cochlear Nucleus System, Cochlear Baha System and Cochlear Osia System are one of the most successful products of Cochlear. All these products are easy to use and comfortable, which is the reason for their immense popularity.


Cochlear Implants (CI)

This is the most commonly and widely used hearing implant. The three components of a cochlear implant are the receiver/stimulator, the headpiece, and the speech processor.

  • Stimulator/Receiver - The implanted element is the receiver or stimulator. It has the appearance of a magnetic disc and is roughly the size of a poker chip. It's hidden behind one ear, under the skin. The receiver/stimulator sends a wire to an array of electrodes in the inner ear, which are then supplied into the cochlea. The receiver can be implanted as an outpatient procedure. It may even necessitate a brief hospital stay. It normally takes two to three hours for the surgery to be completed.

  • Headpiece - The microphone and transmitter are housed in a tiny headpiece worn immediately behind the ear. The microphone takes up noises, while the transmitter is in charge of sending the processed sound to the internal system. Small magnets in the transmitter and the implanted device keep the transmitter in position above the implanted receiver/stimulator.

  • Speech Processor - The speech processor converts audio information into electrical data. It can be worn behind the ear or on the body as part of a harness or belt. Special cords connect it to the transmitter and microphone.

Working

A microphone in a cochlear implant picks up sounds and converts them into electrical impulses, which are subsequently transferred to a speech processor either on the body or in the ear. It is then "coded" or converted into a unique pattern of electrical pulses and sent to the coil or headpiece. They're then sent as radio waves to the cochlear implant.

The electrodes on the array that has been implanted in the cochlea receive a pattern of electrical pulses from the cochlear implant. The auditory nerve detects the little electrical pulses and transmits them to the brain, where they are transformed into sound.


What do cochlear implants make the world sound like?

The sound heard through a cochlear implant differs from that heard through a normal hearing. Wearers of cochlear implants who have previously heard sounds naturally perceive the sound as robotic or tinny. The brain adjusts to the new impulses over time, and what is heard becomes more natural.

We can't know exactly how a cochlear implanted person hears the world, and it will differ from person to person, but there are some simulations accessible.


Disadvantages of Hearing Implants

There are hazards associated with every surgical operation involving an implanted medical device. They include the following, according to the FDA:

• Facial nerve injury

• Infection

• Dizziness or tinnitus

• Numbness

• Taste Abnormalities

• Device infection

• Balance problems


What Does the Future Hold for Hearing Implants?

Since the days when animal horns were used as trumpets, we've gone a long way. Artificial Intelligence and digital assistance are likely to play a significant part in the future of hearing aids and implants. Hearing devices with higher sound quality and the ability to track vital signs may one day be permanently implanted in the ear canal. It's reasonable to assume that the age of the “hearables” is just getting started.


References-

https://www.embs.org/pulse/articles/hearing-aid-history-from-ear-trumpets-to-digital-technology/

https://www.mayoclinic.org/tests-procedures/cochlear-implants/about/pac-20385021#dialogId59108769

https://www.nidcd.nih.gov/health/cochlear-implants

https://www.hearinglink.org/your-hearing/implants/middle-ear-implants/