Types of Hearing Aids
Hearing aid technology is changing continually.
In-the-Ear (ITE) Hearing Aid
This type of hearing aid fits in the ear canal and the concha (outer portion of the ear). This is a very popular style for adult hearing aid users but there are drawbacks for use with children who are still growing. They cannot be used with many assistive listening devices including direct audio input FM systems. This style of hearing aid cannot provide adequate amplification for individuals with severe to profound hearing losses.
Behind-the-Ear (BTE) Hearing Aid
With this style of hearing aid the electronics sit behind the ear and the amplified sound is then routed to the ear through the tubing and ear mould. This style of hearing aid can provide the amplification necessary for all degrees of hearing loss from mild to profound. BTE hearing aids can be used with a variety of other assistive devices including FM systems, telephone adaptors, television amplifiers and many others. Because the electronics are behind the ear, BTEs are particularly useful for those with chronic ear infections, excess cerumen (ear wax) and those with small ear canals.
Behind-the-ear hearing aids and ear moulds come in a variety of colours and designs.
Open Fit Hearing Aid
Open fit hearing aids are similar to the behind-the-ear (BTE) style because the amplifier and electronics sit behind the ear. However, these hearing aids typically utilize a slim tube and small tip that sit inside the ear canal. The small tip in the ear results in an open fit without plugging the ear resulting in a more comfortable fit, and can eliminate problems with your own voice. However, the open fit hearing aids are not appropriate for severe hearing losses and are best for persons with mild to moderate high frequency hearing loss.
CROS (Contralateral Routing of Signal)
This hearing aid system is designed for people with one ear that is unaidable (i.e. insufficient hearing to benefit from traditional hearing amplification). The better ear can have normal hearing (CROS Aid) or have some hearing loss as well (Bi-CROS). A microphone is placed on the poorer ear and the sound from that microphone is routed to a hearing aid on the better ear. This provides sound from the “dead” or unusable side of the head. While this does not restore full ability to localize sounds in space, it does provide useful sound information that is not otherwise available to the individual.
A device surgically implanted into the cochlea to bypass the sensory organ to activate the hearing nerve directly. It is designed for individuals with severe-profound sensorineural hearing loss (in both ears) who do not receive benefit from traditional hearing aid amplification. The system consists of a processor that looks like a behind the ear hearing aid, an external magnet that attaches to an internal magnet implanted in the mastoid bone and the actual electrode that is surgically implanted in the cochlea (inner ear). Once implanted, the device is programmed for the individual over several months.
Bone Conduction Amplification Device (BCAD)
This device combines a sound processor with a small titanium fixture implanted behind the ear. The system allows sound to be conducted through the bone rather than via the middle ear – a process known as direct bone conduction. The surgery is minor, and many patients report a wide range of advantages over other hearing devices. BCAD is used for people with chronic ear infections, congenital conductive hearing loss, and/or single-sided deafness.
Source: Canadian Academy of Audiology – Amplification Options