Public Information

About Audiology


What are hearing aids?

Hearing aids are devices that amplify sound to make hearing easier for those with hearing difficulties.

How do hearing aids work?

Hearing aids are designed to compensate for hearing loss caused by parts of the hearing system that are not working effectively. Deficits may affect all sounds or be limited to specific sounds.

Modern electronic hearing aids use a microphone or an array of microphones to detect sounds. The sounds may be coded into a digital representation and are then filtered to best compensate for the hearing loss. Filtered sounds are then produced by a speaker and directed into the ear canal to enhance the sound sent to the eardrum and beyond.

What types of hearing loss are suitable for hearing aids?

Hearing aids are most effective at assisting mild, moderate or severe hearing loss caused by limitations in the transmission of sound through the eardrum and middle ear hearing bones (known as a conductive hearing loss) or reduced function of inner ear sensory cells called outer hair cells (known as a sensory hearing loss).

Hearing aids although usually useful are typically not as effective as cochlear implants for assisting very severe or profound hearing losses.

Hearing aids can also provide some benefit for hearing problems caused by damage to the hearing nerve or brain.

Do I need hearing aids?

Please visit our Hearing Health Checklist

What do hearing aids look like?

Hearing aids come in many different shapes, sizes and colours to suit different needs and preferences. Usually hearing aids can be designed to be smallest when they provide assistance for mild or moderate hearing loss.

Completely in-the-canal style

In-the-ear style

Behind-the-ear style
I’m not old, I don’t need hearing aids!

A common misconception is that the use hearing aids is a sign of old age and should be avoided for as long as possible. This is unfortunate as:

  • Hearing aids are used by people of all ages
  • Studies of the appearance of adults with visible hearing aids shows that perceived age is not significantly increased
  • Experiencing regular hearing difficulties (because hearing aids are not being used) can make people seem older!
Two ears (or two hearing aids) are best

Two ears are better than one! Being able to hear with both ears (binaural hearing) is at least as important as being able to see with both eyes.

If you only use one hearing aid when significant hearing loss is present in both ears there is a risk of auditory deprivation. This is when the brain gradually loses some of its ability to process information from the unaided ear because of a long term lack of sound stimulation. Using two hearing aids minimizes this risk.

Most hearing loss affects both ears therefore the majority of people with hearing loss are good candidates for two hearing aids. In New Zealand over 85% of suitable new hearing aid users opt for two hearing aids.


Click to enlarge

Click to enlarge

Click to enlarge

Click to enlarge

If cost is an important factor in your decision then it may be best to get two less costly hearing aids than one that has a higher price. Important benefits of binaural hearing (or use of two hearing aids) are:

  • You get the best ability to determine where sounds are coming from
  • Understanding speech in noisy surroundings is easier for you
  • Your risk of auditory deprivation is greatly reduced
  • The sound picture you experience will be fuller and more comfortable

Hearing Aid Cleaning and Care

Information about Hearing Aid Cleaning and Care can be found here.

Hearing Aid Technology

Digital Hearing Aids
  • Over 90% of new hearing aids are digital
  • Many use computer processing to reduce non-speech background noise
Directional Microphones
  • Hearing aids with two microphone entry points or two or three microphones can be used to enhance sounds from particular directions.
  • Directional microphones are typically used to help people concentrate their hearing on a particular conversation in the presence of background noise or when in a group of people.
  • A range of different hearing aid styles ands sizes are available with directional microphones
FM System
  • Device that transmits sound wirelessly from a transmitter (placed near the source of the desired sound) to a receiver that passes the sound to the user often via hearing aids.
  • Typically used to help hearing impaired children hear the teacher in a classroom environment or by hearing impaired adults in seminar or meeting situations.
Remote Controls
  • Controls the specific functions of hearing aids such as adjusting the volume or changing to a different listening programme used for a different hearing environment.


website design by indigo