Hearing loss can be divided into two types: conductive hearing loss (usually due to a problem in the external or middle ear) or sensorineural hearing loss (caused by a problem with the inner ear (cochlea) or hearing nerve pathway).
Some of the signs that your child may have difficulty hearing include:
Some of the signs you might notice that indicate you have a hearing loss include:
Hearing loss can occur to varying degrees, from slight (you only miss out on quiet sounds) through to profound (you cannot hear even very loud sounds).
Treatments for hearing loss vary depending on what has caused the hearing loss. Many of the causes of conductive hearing loss can be treated using medication or surgery by a GP or an Ear Nose and Throat specialist. Most sensorineural types of hearing loss cannot be treated with medication or surgery, and require the use of a hearing aid fitted by an audiologist. The type of hearing aid you need depends on the degree and shape of your hearing loss, as well as your choice of the style, comfort and level of technology of the hearing aid.
An Auditory Brainstem Response test (ABR) evaluates how well the sounds travel along the hearing nerve pathways to a particular part of the brain called the brainstem. An ABR may be recommended for a variety of reasons. It can be used to determine the integrity of the auditory pathway (diagnosis of Auditory Neuropathy Spectrum Disorder), or to estimate hearing thresholds in newborns, older children and adults who cannot perform reliably on a behavioral hearing test.
Stickers (recording electrodes) are carefully placed onto the head and soft foam tips are inserted into the ear canals. While the patient is sleeping, quiet clicking sounds are delivered through the foam tips. The hearing nerve’s response to the sound are picked up by the electrodes and then passed on to a computer to be recorded. The recordings are then analysed and can be used to gather a picture of the infant’s hearing. This test can determine the degree, type and shape of a hearing loss.
Depending on the age and compliance of the patient, an ABR may be performed either during natural sleep or, in rare cases, under general anaesthetic.
View the parent information video of an ABR test on a baby.
Visual Reinforcement Audiometry (VRA) is a behavioral method of testing a child’s hearing. This test is used for children between the age of 6 months through to 2 1/2 years old. Your child is seated on your lap in front of a calibrated loudspeaker, or wearing earphones.
When a sound is presented children turn see what the new sound is. This head turn response is rewarded with the display of lights and puppets next to the speaker. Your child's attention is then distracted back to the midline so that further sounds can be presented. Sounds of different pitch and volume are used to measure a picture of your child’s hearing (normal hearing or the degree, type and shape of a hearing loss).
Any test performed through loudspeakers rather than headphones is called "sound field" audiometry and is performed in a sound proof room. Sound field measurements do not test each ear separately; instead they measure the hearing of the better-hearing ear if there happens to be a difference between the ears.
This is a behavioral method of testing a child’s hearing which is appropriate for children from 2 ½ years of age through to five years of age.
The child is taught to perform a play activity such as putting a peg in a peg board whenever they hear a sound. Once the child has understood the game, the volume of the sound is varied to measure the quietest sound the child responds to. This is done for different pitches of sound to gather a picture of the child’s hearing (and audiogram). This test is usually performed using headphones.
Otoacoustic Emission (OAE) testing measures the status of the inner ear (cochlear). It specifically measured the function of the outer hair cells. It is an objective test which means that the patient does not need to respond. It can therefore be used on patients of any age, even sleeping infants.
Pure-tone Audiometry is a behavioral test of hearing used to determine hearing sensitivity for different pitches (frequency) of sound. It is appropriate for any one older than 5 years. The test is performed using earphones and the patient is asked to press a button each time they hear a sound. Pure-tone hearing thresholds indicate the softest sound audible to an individual at least 50% of the time. Hearing sensitivity for each pitch is plotted on a graph called an audiogram.
The most common speech test involves single words being played through headphones. The patient needs to have their best guess at what the words are by saying them out loud into a microphone.
For diagnostic testing the speech test acts as a cross check of the pure tone audiometry results. It can also be used to measure the benefit of hearing aids, and used to compare the performance of different hearing aid types and models.
Tympanometry measures the function of the ear drum and the middle ear. A small soft probe tip is placed at the entrance of the ear canal. Pressure is generated to move the ear drum back and forth. This pressure change is not uncomfortable, and can be likened to the pressure changes when going over a hill in a car.
Acoustic Reflex testing measures a reflex arc which involves the cochlear, the hearing nerve to the level of the brainstem, and the muscles attached to the ossicles in the middle ear.
This appointment involves a discussion about the listening needs of a patient. The cost, the level of technology, and the different styles of hearing aids are explained. Different funding options are identified by the audiologist. The audiologist and the patient can then decide on a hearing aid which best suits the patient. A written quote for the cost of the hearing aids can be given to the patient at the end of this appointment. The fitting of the hearing aids and the start of a hearing aid trial is then performed at the following appointment.
There are entry criteria for this adult rehabilitation service at Waikato DHB. These entry criteria are based on financial need and severity of the hearing loss. Link to referral guidelines.
A test for Auditory Processing Disorder (APD) can be carried out when there are significant concerns about hearing despite the patient having
Waikato DHB is currently accepting referral for children and not adults. Children need to be at least seven years’ of age, due to the current normative data available. For more information, free parent seminars, and to enquire about assessing children younger than seven years please see the Sound Skills website link (http://www.soundskills.co.nz/ (external link) ).