Hearing Aid Technology

Once you get to know the 3 basic types of hearing aids

RIE - Behind The Ear Hearing Aids	ITC/CIC - Canal Hearing Aids	ITE - In-The-Ear Hearing Aids

There are so many other types of hearing aids all using the same technology but vary in size, power and circuitry.

Among the different sizes and models are:

Body worn aids
The body worn hearing aid was the first type of hearing aid invented by Harvey Fletcher while working at Bell Laboratories. They are now rarely used if ever due to new more advantageous developments in technology. These aids consist of a case, an ear mould, and a cord. The case contains the amplifier components. The case is about the size of a pack of playing cards and is worn in the pocket or on a belt. The ear mould is connected to the case via a cord. Because of use of vacuum tubes, body worn aids can provide loud amplification. This made them the first appropriate hearing aid for profound hearing losses. Today, body aids have largely been replaced by Behind-The-Ear instruments.

Extended wear hearing aids
The extended wear hearing aid represents the first "invisible" hearing device. Extended wear hearing aids are hearing devices that are non-surgically placed in the ear canal. This form of hearing aid was invented by Adnan Shennib. One advantage to these hearing aids is there worn up to several months at a time without removal.  They work by directing sound into the ear canal from the outer ear. Made of soft material designed to contour to each user designed for those with mild to moderately severe hearing loss. Traditional behind the ear or in the ear hearing aids require daily insertion and removal were the extended wear hearing aids are worn continuously and then replaced with a new device. Their close proximity to the ear drum results in improved sound directionality and localization, reduced feedback, and improved high frequency gain.
Those wearing the extended wear hearing aids can change volume and settings without requiring a hearing professional. The extended wear hearing aid is very useful for active individuals because their design protects against moisture and earwax and can be worn while exercising, showering, etc. Because of the extended wear hearing aids placement within the ear canal making them invisible to observers, the extended wear hearing aids are therefore more popular with those who are self-conscious about the aesthetics of behind the ear or the in the ear hearing aid models. As with all hearing devices, compatibility is based on an individual’s hearing loss, ear size and shape, medical conditions, and lifestyle.

Open-fit device hearing aids:
The "Open-fit" or "Over-the-Ear" hearing aids is categorized by a small plastic case behind the ear, and a very fine clear tube running into the ear canal. "Open-fit" or "Over-the-Ear" hearing aids are considered a small behind-the-ear type device much like the behind the ear and the in the ear hearing aids. Inside the ear canal, a small soft silicone dome or a moulded, highly vented acrylic tip holds the tube in place. This design is intended to reduce the occlusion effect. Equally, because of the increased possibility of feedback and an open fit allows low frequency sounds to leak out of the ear canal. The "Open-fit" or "Over-the-Ear" hearing aids are limited to moderately severe high frequency losses.

Personal programmable or consumer programmable hearing aids:
The personal programmable, consumer programmable, consumer adjustable, or self programmable hearing aid allows the person with hearing loss to adjust their own hearing aid settings to their preference using any personal computer. Personal programmable hearing aid manufacturers do adjust the personal programmable hearing aids to fit your type of hearing loss using the test results the audiologist took. It's then up to the person with the hearing loss to re-program the hearing aid if necessary, as required for their type of hearing loss.
The personal programmable, consumer programmable, consumer adjustable, or self programmable hearing aid is available in most hearing aid styles. This type of hearing aid differs from traditional hearing aids only in that they're adjustable by the person with the hearing loss.

Disposable hearing aids
The disposable hearing aid is a hearing aid with a non-replaceable battery. The disposable hearing aid is designed to use power sparingly, in turn the battery lasts longer than batteries used in traditional hearing aids. Disposable hearing aids are meant to remove the task of battery replacement and other maintenance chores such as adjustments or cleanings. The  disposable hearing aid is seldom used to date there are only 2 companies that make this type of hearing aid. Songbird Hearing and Lyric are the two companies that supply the disposable hearing aid. Both supply the digital disposable hearing aid but both are used in very different ways by the person with hearing loss. The Songbird hearing aid is considered a behind the ear hearing aid that is bought online and worn like any other behind the ear hearing aid. Whereas the Lyric is implanted deep in the ear canal by a professional. When the Lyric hearing aid runs out it must be removed and replaced by a professional.

Bone Anchored Hearing Aids:
The bone anchored hearing aid is an auditory prosthetic which must be implanted surgically. Using the skull as a pathway for sound the bone anchored hearing aid sends the sound to the inner ear. For those with conductive hearing loss the bone anchored hearing aid bypasses the external auditory canal and middle ear, stimulating the functioning cochlea. For those with unilateral hearing loss the bone anchored hearing aid uses the skull to conduct the sound from the deaf side to the side with the functioning cochlea.
For children under 5 the bone anchored hearing aid is worn on a headband. Over the age of 5 the bone anchored hearing aid is a titanium post surgically embedded into the skull with a small abutment exposed outside the skin. The bone anchored hearing aid sound processor sits on this abutment and transmits sound vibrations to the external abutment of the titanium implant. The implant then vibrates the skull and inner ear, which stimulate the nerve fibres of the inner ear, allowing one the capability of hearing.

Eyeglass Hearing Aids:
During the late 1950s through 1970s in an era when thick-rimmed eyeglasses were popular also before the in-the-ear aids became common, people who wore glasses and hearing aids frequently chose a type of hearing aid that was built into the temple pieces of the glasses. Unfortunately the combination of glasses and hearing aids was inflexible due to the fact the style of frames during that time was very limited. The user had to wear both hearing aids and glasses at once or wear neither.
With today's technology the person with hearing loss, who as well wears glasses tend to use the in-the-ear type or the behind the ear where the hearing aid sits neatly alongside the arm of the glasses.
In some specialized situations hearing aids are still build into the frame of eyeglasses. This is used in most cases where the person with hearing loss has hearing loss mainly in one ear. It's then used in a manner where the sound from a microphone on the "bad" side can be sent through the frame to the side with better hearing. Then again this can also be achieved by using CROS or bi-CROS style hearing aids, which are now wireless in sending sound to the better side.
Recently a new type of eyeglass hearing aid has been introduced. These are called hearing glasses which feature directional sensitivity, four microphones on each side of the frame effectively work as two directional microphones, which are able to separate between sound coming from the front and sound coming from the sides or back of the hearing aid user. This improves the signal-to-noise ratio by allowing for amplification of the sound coming from the front, the direction in which the user is looking, and active noise control for sounds coming from the sides or back. It's only been recently that they were able to produce a hearing aid small enough to be put in the frame of the glasses. Unfortunately this new hearing aid is only available in the Netherlands and Belgium. As the need increases they will be available to those with hearing loss that prefer this type.