|Posted on June 21, 2010 at 6:08 PM|
By Dr Sonia Suprabha Venugopal, ENT Specialist Bangalore
A hearing aid is a small electronic device that you wear in or behind your ear. It is a device designed to help utilize the auditory system to its fullest. Essentially the function of a hearing aid is to make everything louder. When one loses their hearing, they lose their ability to detect soft sounds. The hearing aid just makes these soft sounds loud enough to be audible. It makes some sounds louder so that a person with hearing loss can listen, communicate, and participate more fully in daily activities. A hearing aid can help people hear more in both quiet and noisy situations. However, only about one out of five people who would benefit from a hearing aid actually uses one.
Hearing Aids are of different types and the hearing aid is recommended based on the individual person and takes into consideration several factors including
Hearing Aid Mechanism
A hearing aid has three basic parts: a microphone, amplifier, and speaker. The hearing aid receives sound through a microphone, which converts the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them to the ear through a speaker.
Even the best hearing aids do not "cut out" background sounds completely,however, utilizing the latest technology it is possible to maximize the hearing in difficult listening situations.
Types of Hearing Aids
The most common types of hearing aids are those that are worn in or behind the ear, but there are others, such as implantable hearing aids, which can be used in certain situations (see below).
Externally worn hearing aids
The most commonly used type of aid is the behind-the-ear hearing aid, where all the electronic components are contained in a skin-coloured plastic case that sits behind the ear.
Cosmetically more popular is the in-the-ear hearing aid, which is a smaller, more compact device worn in the ear canal, but it is inappropriate for people with severe deafness because it is not powerful enough to compensate for their hearing loss. It is not suitable for those with some loss of manual dexterity, because the control switches are quite small.
Even smaller is the completely-in-the-canal hearing aid, which is virtually invisible when worn. Again, because of its small size, its casing is too small to be able to hold a very powerful amplifier and so it is only useful for mild hearing losses.
For people with very severe deafness, the electronic components needed to amplify sounds can become too bulky to fit into small hearing aids and a separate body-worn hearing aid with larger switches would be most sui table. However, with the advances in hearing aid technology this type of hearing aid is now much less common.
People with a conductive hearing loss may benefit from a device which is held in place behind the ear with a headband or 'alice band'. This is known as a bone conduction hearing aid.
People tend to benefit from this type of hearing aid if they have problems in the ear canal or middle ear, for example because of recurrent ear infections, previous surgery, or anatomical abnormalities such that they are unable to wear conventional hearing aids. Bone conduction aids can work very well, but can be quite bulky and obvious, and a more sophisticated type of bone conduction aid has been developed. This is the bone anchored hearing aid [BAHA]
Bone-anchored hearing aid
For people with a conductive hearing loss, or for people who are unable to wear conventional hearing aids because of previous ear surgery or ear malformation, the bone-anchored hearing aid is proving to be an excellent alternative.
As mentioned above, bone conducting ‘alice bands’ are bulky and can be quite sore to wear, because they have to press hard on the skin behind the ear to transmit vibrations to the skull. The BAHA consists of a small screw that is implanted in the bone behind the ear during a short operation (usually, but not always, under general anaesthetic).
After the area has healed, a small case containing all the electronic components of the hearing aid can be easily clipped on and off. The hearing aid gives excellent clarity of hearing and leaves the ear canal open so that patients who have been troubled by constant ear infections when using other types of hearing aids find they usually clear up very quickly.
How Does a Hearing Aid Help in hearing?
A hearing aid magnifies sound vibrations entering the ear. Surviving hair cells detect the larger vibrations and convert them into neural signals that are passed along to the brain. The greater the damage to a person’s hair cells, the more severe the hearing loss, and the greater the hearing aid amplification needed to make up the difference. However, there are practical limits to the amount of amplification a hearing aid can provide. In addition, if the inner ear is too damaged, even large vibrations will not be converted into neural signals. In this situation, a hearing aid would be ineffective.
Who can benefit from a hearing aid?
In theory, anybody with a hearing loss, whatever their age, who is having difficulty in following a normal conversation or listening to the TV or radio will benefit. However, you must have some residual hearing, however little, in order to benefit from a hearing aid. If no sound whatsoever is being heard, a cochlear implant may be indicated.
Adjusting to your Hearing Aid
Are two hearing aids better than one?
Yes it is better to have two hearing aids. Wearing two (binaural) hearing aids allows more information to reach your brain and makes it easier to hear speech against background noise.
Care of your Hearing Aid