Children with an auditory processing disorder (APD) can typically hear information at normal levels but have difficulty attending to, storing, locating, retrieving and clarifying that information to make it useful for academic and social purposes. Audiology at ADHB offers diagnostic testing for APD to those children older than seven who have passed a screening test of attention and cognition. Management and diagnosis of children with APD is performed in the private sector at a cost. See the NZAS website, https://www.audiology.org.nz.

Hearing loss can be divided into two types: conductive hearing loss (caused by some sort of mechanical problem in the external or middle ear) or sensorineural hearing loss (caused by disorders of the inner ear, hearing nerve or associated brain structures). Conductive hearing loss is often reversible and can be due to: blockage of the ear by e.g. wax, inflammation, infections or middle ear fluid poor sound conduction because of e.g. holes or scarring in the eardrum or the bones of the middle ear (ossicles) becoming fixed and rigid. Sensorineural hearing loss is generally not reversible and can be caused by: genetic make-up (this could include congenital conditions i.e. those you are born with, or late-onset hearing loss) head injury tumours infections certain medications exposure to loud noises the aging process (a significant hearing loss is experienced by about one third of people aged over 70 years). Some of the signs you might notice that indicate you have a hearing loss include: having to turn up the volume on the TV or radio finding it hard to hear someone you are talking with finding it hard to hear in a group situation where there is background noise e.g. in a restaurant having to ask people to repeat themselves you find people's speech is unclear - they are mumbling Some of the signs that your child may have difficulty hearing include: unclear speech or delayed speech development lack of responsiveness to sound poor receptive language. Hearing loss can be partial (you can still hear some things) or complete (you hear nothing) and may occur in one or both ears. Treatment Treatments for hearing loss range from the removal of wax in the ear canal to complex surgery, depending on the cause of the loss. One of the most common treatments for hearing loss in children and adults is the use of hearing aids. The type of aid you get depends on the cause of your hearing loss and how bad it is, as well as what your preferences are in terms of comfort, appearance, cost and lifestyle. For information on funding for hearing aids refer to the section on Costs.

An Auditory Brainstem Response test (ABR) evaluates how well the sounds travel along the hearing nerve pathways to the brainstem. An ABR may be recommended for a variety of reasons. It can be used to determine the integrity of the auditory pathway, or to estimate hearing thresholds in newborns, older children and adults who cannot perform reliably on a behavioural hearing test. Recording electrodes are 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. Nerve responses elicited by the sound are picked up by the electrodes and then passed on to a computer to be recorded. The recordings are analysed to determine if they fall within normal limits. The results are then reported to the patient's GP or to the Ear, Nose and Throat (ENT) specialist if further medical evaluation is required. 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.

Visual Reinforcement Audiometry (VRA) is a behavioural audiometric test obtained in a sound-proof room. 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 or at a small table in front of a calibrated loudspeaker, or wearing headphones. When a sound is presented, the infant's head-turn response toward the sound source is rewarded by activation of a puppet mounted near the loudspeaker. Your child's attention is then distracted back to the midline so that additional sounds can be presented. Any test performed through loudspeakers rather than headphones is called "sound field" audiometry and does not test each ear separately; rather, sound field audiometry yields an audiogram for the better-hearing ear if there happens to be an ear difference in hearing. However, if your child tolerates wearing earphones, then each ear can be assessed seperately.

Appropriate for testing children from 30 months through to five years of age. Your child is conditioned to perform a play activity (e.g. dropping a block in a bucket) whenever they hear a sound. Once the child is conditioned, threshold of hearing can be determined by decreasing signal intensity. This test is usually performed under headphones to obtain ear- and frequency-specific information.

Otoacoustic Emission (OAE) testing measures the status of the inner ear (cochlea), specifically hair cell function. It is an objective test that can be used on patients of any age. The test can even be performed on sleeping babies because it does not rely on behavioural responses.

Pure-tone Audiometry is a behavioural test used to determine hearing sensitivity and is conducted in a soundproof room. The test is performed using headphones and the patient is asked to respond each time they hear a sound. Pure-tone thresholds indicate the softest sound audible to an individual at least 50% of the time. Hearing sensitivity is plotted on an audiogram, which is a graph displaying intensity as a function of frequency.

Word recognition/speech discrimination tests the ability to hear correctly a set of words or sentences. You will be asked to repeat back what you heard at the different intensities.

Tympanometry measures the function of the middle ear. A small soft probe is placed in the ear canal then the response of the ear drum to pressure changes is measured. Acoustic Reflex testing measures a reflex arc that goes between the middle ear and brainstem in the auditory system which is elicited by an intense stimulus. These tests do not directly assess hearing ability, but are interpreted in conjunction with other test results.

ADHB provides adult hearing aid fitting services only to those who meet the Enable criteria for the Hearing Aid Funding Scheme with a bilateral hearing loss from childhood (moderate-severe or worse) or has a "dual disability" or if they have suffered a sudden or severe hearing loss average of 65dB in the worst 3 frequencies of .5 kHz to 4 kHz (in the better ear). Evidence of this hearing loss needs to be provided for the referral to be considered. Free hearing checks for adults are widely available through private audiology clinics with little to no waiting times. Also some private clinics are now offering hearing aids at greatly reduced prices or offer a "pay as you go" service. ADHB will see the patient while the hearing aid is still under warranty and for 6 years if they still meet the eligibility criteria for to ADHB. If your patient does not meet the above criteria they will have to be seen in the private sector. A list of private clinics can be found on the NZ Audiological Society website http://www.audiology.org.nz/.