Globally, millions of individuals suffer from loss of hearing and this could range from mild, moderate, to severe. Advancements in audiology, a field of science that deals with hearing, and related disorders, has significantly helped many individuals with impaired hearing.
In the past decades, the technology behind hearing aids, cochlear implants, and assistive listening devices have developed immensely. This article discusses some of the recent developments in hearing technology.
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Common Types of Hearing Loss
Typically hearing loss is of three types, these are described below:
(a) Conductive hearing loss is associated with mechanical problems where the sound faces trouble traveling from the outer ear to the eardrums and middle ear bones. Conductive hearing loss could be caused due to too much ear wax, the presence of fluid in the middle ear, otosclerosis, a hole in the eardrum, or if some objects, like cotton from earbuds, get stuck in the ear canal, etc. Many of these problems could be corrected via medicine or surgery.
(b) Sensorineural hearing loss is one of the most common forms of hearing loss that occurs due to nerve damage in the inner ear. This condition could be caused by acoustic trauma (noise exposure), acoustic neuroma, aging, head injury, etc. Although sensorineural hearing loss is permanent, it can be improved via amplification devices, such as hearing aids, cochlear implants, and assistive listening devices.
(c) Mixed hearing loss, which is basically a combination of the aforementioned types of hearing loss.
Although the hearing aid technology has improved significantly over the past few decades, the core design has remained constant. A typical hearing aid contains four basic parts, i.e., a microphone, a processor, a receiver, and a power source. The function of the microphone is to pick up sounds from the surrounding and passes them to the processor, which amplifies the signal. This signal is then passed to the receiver which delivers to the ear canal. The entire process is powered via a battery.
Meghan Spriggs, audiologist and assistant clinical professor at UC San Diego, stated that recent hearing aid devices are significantly superior to the ones that were available a few years back. Some of the key features included in today’s hearing aids are sleek design, smaller size, built-in rechargeable batteries, improved microphone technology, compatibility with Bluetooth-enabled devices, and better protection against wax, moisture, and dust.
Hearing Aids, Cochlear Implants and Assistive Listening Devices
Hearing aids that are available today can be specially customized for an individual hearing loss, i.e., the device can be adjusted according to an individual’s ear canal. Generally, individuals with severe hearing loss require a cochlear implant. The key benefit of a cochlear implant, compared to hearing aids, is that it can improve the ability to hear and understand speech. Recent developments in cochlear implants have enabled children as young as nine months to wear the device.
Cochlear implant technology is growing rapidly and the most advantageous part is that most of the improvements are housed in the processor, which is present in the external part of the device. This implies that patients who underwent cochlear transplant surgery some years ago can easily access the majority of the latest developments. Sometimes, assistive listening devices (ALDs) are paired with hearing aids and cochlear devices to further improve hearing.
There are different types of ALDs, such as personal amplifiers which contain handheld amplifiers with a microphone that can intensify voices and sounds. Improvements in ALDs also include amplified telephones which have helped individuals with difficulty to hear voices on telephones.
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Recent Advancements in Hearing Technology
The advancements in technology have made hearing aids more automatic and added many interesting features that have enabled individuals with hearing impairment to communicate with their surroundings via flashing lights or vibrating devices. Recently, hearing aids have also been coupled with a smoke detector and sounds of doorbell or alarm.
Wireless technology has enabled two hearing aids to function together as one complete system. This technology is based on binaural processing, which mimics the brain's ability to process information coming from both ears and minimizes manual adjustments. Information transfer rate in wireless hearing aids is in nanoseconds, faster than the detection ability of the human brain. Some of the other recent developments in hearing technology are discussed below:
Amplification of specific bands: All hearing aids process sound, i.e., after receiving the sound, the hearing aids section it into bands of sounds (called channels) and digitize before amplification. An advanced hearing aid supports better flexibility to amplify the band of sounds according to one’s needs.
For instance, if an individual has only high-frequency hearing loss, an advanced hearing aid would enable amplification of sounds that are within a high-frequency band only. On the contrary, a lower-end model of hearing aid would amplify both mid-and high-frequency sounds irrespective of the requirement of the individual.
Bluetooth compatibility: Bluetooth compatibility is a wireless feature that enables hearing aids to connect with other devices, such as phones. Bluetooth technology has improved the signal-to-noise ratio and removed feedback from the microphone.
Telecoil (tcoil): This wireless feature enables picking up electromagnetic signals from compatible telephones. As the signals reach the hearing aid’s processor without requiring microphones, the signal-to-noise ratio is substantially improved.
Rechargeable batteries: Hearing aids with rechargeable batteries solves the problem of frequent swapping of batteries.
Noise reduction: Digital noise reduction system is one of the important features that determines if a certain sound contains unwanted noise. If an undesirable noise is detected, it reduces the level of noise. Hence, the listening comfort could be increased via this feature. Similarly, an impulse noise reduction system detects transient loud noises, e.g., dishes rattling and car keys rattling, and softens them immediately. A wind noise reduction system can identify the impact of the wind blowing across the hearing aid microphones and, therefore, does not amplify them.