Types of Hearing Aids

With new advances in hearing aid technology some hearing aids are impossible to be seen from the outside and allow tailoring of the sound to the patient's specific hearing loss. Occasionally and in some cases a more affordable assisted listening device such as an amplified telephone or headphone are all that is required to improve a person's quality of life.

There are 3 basic types of hearing aids:

Behind-the-ear:

The behind the ear hearing aid consist of a hard plastic case worn behind the ear and connected to a plastic ear mold that fits inside the outer ear. The electronic parts or the amplification system are held in the case behind the ear. Sound travels from the hearing aid through the tube to route the sound from the hearing aid case to the ear mold and into the ear. Typically the sound is routed acoustically. Sometimes the sound is routed electrically. The speaker is located in the ear mold instead of in the case. Behind the ear hearing aids are used by people of all, from those with mild hearing loss to those with profound hearing loss.
A new kind of behind the ear aid is an open-fit hearing aid. Small, open-fit aids fit behind the ear completely, with only a narrow tube inserted into the ear canal, enabling the canal to remain open. For this reason, open-fit hearing aids may be a good choice for people who experience a build-up of earwax, since this type of aid is less likely to be damaged by such substances. In addition, some people may prefer the open-fit hearing aid because their perception of their voice does not sound “plugged up.”

Behind the ear hearing aids have several advantages over other types of hearing aids. One advantage is they tend to be more durable because the electrical components are located outside the ear, in turn reducing the amount of earwax and moisture the electrical components are subjected to. Another advantage of the behind the ear hearing aids is that it can be connected to assistive listening devices, such as classroom FM systems. Most importantly if the earmold no longer fits the earmold can be replaced for a fraction of the price of a new hearing aid. Behind the ear hearing aids are hearing aids typically prescribed for children, children need a durable hearing aid that has assistive listening devices as well children outgrow the size of the earmold.

Behind the ear hearing aids now include miniature behind the ear hearing aids with thin hair-like sound tubes. These are often less visible than In-The-Ear hearing aids that use a larger vent than other hearing aid types. This keeps the ear canal more open, which allows sound to enter the ear without being amplified. This is helpful for listeners with normal hearing in the lower frequencies. Miniature behind the ear hearing aids are generally used for mild to moderate high frequency losses.

In-the-ear hearing aids:

The in the ear hearing aid fits completely inside the outer ear and is as well used for mild to severe hearing loss. In the ear hearing aid devices fit in the outer ear bowl called the concha. Like the behind the ear hearing aid the case holding the electronic components is made of hard plastic and are custom made to fit each individual's ear. Some in the ear hearing aids aids may have certain added features installed, such as a telecoil. A telecoil is a small magnetic coil that allows users to receive sound through the circuitry of the hearing aid, rather than through its microphone. This makes it easier to hear conversations over the telephone. A telecoil also helps people hear in public facilities that have installed special sound systems, called induction loop systems. Induction loop systems can be found in many churches, schools, airports, and auditoriums.
Traditionally, in the ear hearing aids are not been recommended for young children because their fit could not be as easily modified as the earmold for a behind the ear hearing aids, thus the aid had to be replaced frequently as the child grew. However, there are new in the ear hearing aids made from a silicone type material that mitigates the need for costly replacements.

The advantages to this type of hearing aid: the sound of the hearing aid is arguably smoother than that of a traditional behind the ear hearing aid. With a traditional behind the ear hearing aid, the amplified signal is emitted by the speaker/receiver which is located within the body of the hearing aid (behind the ear). The amplified signal is then directed to the ear canal through an acoustic tube, which creates a peaky frequency response. With a right in the ear hearing aid, the speaker/receiver is right in the ear canal and the amplified output of the hearing aid does not need to be pushed through an acoustic tube to get there, and is therefore free of this distortion. Also the right in the ear hearing aid can typically be made with a very small part behind-the-ear and the wire connecting the hearing aid and the speaker/receiver is extremely inconspicuous. For the majority of people this is one of the most cosmetically acceptable hearing devices. Lastly the right in the ear hearing aid is suited to "open fit" technology so can be fitted without plugging up the ear, offering relief from occlusion.

Canal hearing aid:

The canal hearing aid fits into the ear canal and is available in different styles. In the ear hearing aids are smaller filling only the bottom half of the external ear. Mini in the canal hearing aids and completely in the ear hearing aids are often not visible unless you look directly into the wearer's ear. These hearing aids are intended for mild to moderately-severe hearing loss only. Completely in the ear hearing aids are usually not recommended for people with good low frequency hearing, as the occlusion effect is much more perceivable.
Because they're so small, canal aids may be difficult for a hearing impaired person to adjust and remove. Also canal hearing aids have less space available for batteries and additional devices, such as a telecoil. This type of hearing aid is seldom recommended for young children or for people with severe to profound hearing loss due to the fact there reduced size limits their power and volume.
The invisible in the ear hearing aid is the type of hearing aid not visible when worn. It fits deeper in the canal than other types of hearing aids so it's out of view even when looking directly in to the ear bowl or concha. A comfortable fit is achieved because the shell of the hearing aid is custom-made to an individual ear canal after taking a mold of the patient’s ear. Invisible hearing aid types use venting and their deep placement in the ear canal to give a more natural experience of hearing. Unlike other hearing aid types, with the invisible in the ear hearing aid  aid the majority of the ear is not blocked or occluded by a large plastic shell. This in turn allows sound to be collected more naturally by the shape of the ear, and can travel down in to the ear canal as it would with unassisted hearing. Instead of taking out the invisible in the ear hearing aid to change memory or volume settings, some allow the wearer to use their mobile phone as a remote control to alter settings. It's also worth noting that invisible in the ear hearing aid types are most suitable for users up to middle age, but are not suitable for more elderly people.