Frequently Asked Questions

What is Auditory Processing Disorder (APD)?

Auditory Processing Disorder (APD) is a hearing disorder in which the ears process sound normally but the hearing centres and circuits of the brain don’t correctly process incoming information. This can affect understanding, especially in challenging listening situations such as in the presence of other distracting sound, or when listening to complex information or instructions. APD is thus often referred to as a hearing problem in which “the brain can’t hear”.

See the technical definition of APD »

What is Central Auditory Processing Disorder (CAPD)?

This is an interchangeable term with Auditory Processing Disorder (APD).  There is academic debate over which is the more appropriate term.

Is APD a form of hearing loss?

The answer to this question depends on the definition of “hearing”.  In the general sense that “hearing” means hearing and understanding, then APD is a form of hearing loss. People with APD tell us that they miss parts of speech.  They don’t ‘hear’ everything a normal hearing person hears.  There is a loss of hearing.

A more specific and technical approach reserves the term “hearing” to refer to sound reception at the ear irrespective of whether it is understood. Hearing in this sense is measured by recognition of tones on a standard pure tone audiogram test.  APD is not detected by this test.  Using this definition of hearing, APD is described as an auditory disorder in the absence of a hearing loss.

Semantic issues apart, we think that regarding APD as something outside “hearing loss” can have adverse consequences for services for people with APD.  It enables hearing services agencies to exempt themselves from providing funding or services for APD.  It can lead to APD being misclassified as for example a learning disability or language disorder.  (Those are consequences, not the primary disorder.)  It can also lead to professionals without audiological qualifications regarding themselves as diagnosticians of APD and/or providers of primary treatment services for APD.

What is Amblyaudia?

Amblyaudia is a hearing weakness on one side when the cause is not in the ear itself. Amblyaudia is like a hearing equivalent of amblyopia or ‘lazy eye’.  Up to half of children with APD show weaker performance in one ear on certain tests.  The two ears don’t work together for optimal hearing.  Fortunately amblyaudia can be successfully treated.  SoundSkills is the only APD clinic in New Zealand providing assessment and treatment for Amblyaudia.

Read more on amblyaudia. »
Read more on amblyaudia treatment. »

What are the symptoms of APD?

Children with APD are usually of normal intelligence and pass standard hearing tests, but they sometimes have difficulty understanding what they hear.  A child with APD will typically exhibit some of the following signs.

  • difficulty comprehending spoken language unless brief, clear and simple
  • hearing difficulty against other background sound
  • poor listening skills
  • slowness in processing spoken information
  • poor auditory memory (difficulty attending to and remembering spoken information)

Other possible signs include

  • insensitivity to tone of voice or other nuances of speech
  • sensitivity to excessive auditory stimulation (eg noisy situations)
  • extreme tiredness after school
  • problems with comprehension, language, phonics, spelling, vocabulary, reading or written language

What causes APD?

Common causes of APD are:

  • hereditary factors
  • birth-related factors
  • maturational delay
  • glue ear (otitis media) in infancy or early childhood

Read more on APD and otitis media »

What effects does APD have on hearing?

People with APD miss parts of speech if it is too fast or too complex or if there is other competing sound present.  They may completely miss, or misunderstand, spoken information.  We need to be able to distinguish sounds of importance from all the sound around us.  We also need to know all the sounds (phonemes) that make up our language.  We need to be able to correctly distinguish between the different phonemes. Apart from not hearing correctly, children growing up with APD have difficulty correctly learning the phonemes which make up our language.  Poor phonological awareness in turn contributes to their learning difficulties.

People with APD may also have poor skills at detecting nuances of language such as changes in the meaning of statements denoted by a change in pitch or emphasis, for example to change a statement into a question, a demand or a joke.

Read more on hearing skills that are affected by APD »

How does it sound to have APD?

Adults with APD, particularly if it resulted from an accident so they have prior experience of good hearing, can provide insight into the experience of hearing with APD.  

Louise Carroll QSO, JP, GDPPA , MPM, Chief Executive Officer of the National Foundation for the Deaf Inc has Auditory Processing Disorder and uses hearing aids and an FM system.  She describes her hearing experience as follows.

“Without my hearing aids or FM system, speech seems fast, fragmented and confusing.  Voices lack tonality. My directional hearing is poor and voices from behind are particularly difficult to hear. It’s very difficult to distinguish a voice from any other sound that is present.  For example, if the refrigerator switches on (a sound barely noticeable to most people) it seems to me to swamp anyone speaking.

With my hearing aids I hear much better, losing only perhaps 25% of speech.  With both my hearing aids and FM system I can usually hear 100%. But I am still exhausted from listening at the end of the work day and want to take my hearing aids off as soon as I get home.”

One Auckland child with APD when first fitted with remote microphone hearing aids echoed the comment about lack of tonality in voices.  He listened to the teacher and teacher aide for a moment then remarked with surprise that they had different voices.  “I didn’t know people had different voices” he said.

At what age can a child be tested for APD?

A number of factors affect the age at which APD can be diagnosed with certainty. The central auditory system continues to mature into adolescence.  In children under seven years there is considerable variance in the maturation of the auditory system.  Also some tests have been evaluated and proven on younger children than others (“test norms”).  

With current tests Auditory Processing Disorder can be readily diagnosed from about six years of age and considerable information about auditory processing skills can be measured at age five.  Some information can be determined at age four.  Below age seven however a confirmed diagnosis of APD should be made with caution. Sometimes where there are strong indicators of APD at a young age the audiologist may make a “provisional” diagnosis of APD or state that the child is “at risk” of APD.  What is important is that as much information as possible is collected and treatment is commenced as early as possible if the child is clearly experiencing auditory impairment.  The earlier treatment begins the better.

Why are additional tests besides the APD tests needed?

The results of auditory processing tests cannot be properly evaluated in isolation. In order to diagnose Auditory Processing Disorder in a child the audiologist must be able to rule out

  • “peripheral” hearing loss (hearing loss in the outer, middle or inner ear)
  • cognitive impairment (insufficient cognitive skill to perform the APD tests reliably)
  • language impairment (language skills must be at a sufficient level to cope with the speech-based APD tests)

The evaluation should therefore also include

  • standard hearing tests
  • cognitive screening
  • language screening.

Questionnaires about auditory skills and listening behaviour are also usually requested from the teacher and parents to provide additional information about any auditory problems.

Will my child grow out of it?

In the minority of cases where the Auditory Processing Disorder is due only to maturational delay the child may grow out of it.  But there is no sure way of knowing if maturational delay is the cause.  Meanwhile the child is losing ground at school.  So treatment to help the child catch up in auditory skills and language development is still usually advisable.

Can APD be treated?

Yes. Because of neuroplasticity APD is very treatable.  Some treatments address the hearing disorder itself, and some treat the language and learning consequences that result from not having heard correctly in the past.
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What are FM systems?

FM stands for Frequency Modulation, a type of radio transmission.  DM, Digital Modulation, is another newer type of radio transmission which is also starting to be used in the field of deafness technology.

“FM system” usually refers to an assistive listening device used by people with hearing impairment as an attachment to hearing aids or cochlear implants to enhance the capabilities of the hearing aids or cochlear implants. These accessory systems include two parts, a transmitter microphone worn by the speaker (eg partner, parent, teacher) and the receivers attached to the hearing aids or cochlear implants.  FM systems improve hearing over a distance and improve hearing when there is background noise present.  

FM systems worn by individuals are increasingly referred to as “personal” FM systems to distinguish them from classroom sound field systems in which the teacher wears an FM transmitter that sends her voice to loudspeakers.

People whose “hearing loss” is in the central auditory system rather than the ears (APD) frequently benefit from hybrid hearing aid/FM systems in which the speaker wears the transmitter microphone and the person with the hearing loss wears special hybrid hearing aid/FM receivers.  These special hearing devices are also confusingly referred to as FM systems or personal FM systems. Because they are different and unique, and are the primary assistive device, not just accessories to other aids, we believe that they should be more specifically referred to as remote microphone hearing aids or RM hearing aids.

What are remote microphone hearing aids?

RM or remote microphone hearing aids are hearing aids that incorporate a radio (eg FM) receiver. They are worn by the person with the hearing loss.  The “remote” transmitter microphone is worn by the person speaking, eg parent, teacher, partner.  See answer to question “What are FM systems?”

How long do children with APD need to wear remote microphone hearing aids?

Not all children will need to wear assistive listening devices long term.  But there is no research data on this exact question.  Research shows that beneficial effects on auditory skills from remote microphone hearing aids are observable after two to eight months. 

Clinical experience shows that some children don’t need their remote microphone hearing aids any more after a couple of years.  It would be reasonable to assume that every child will be different, and that the earlier intervention occurs the more effective it is likely to be.

Can APD be treated by speech and language therapy?

Language therapy does not directly treat the hearing disorder itself in people with APD. Auditory training (such as amblyaudia correction or training of spatialised hearing skills) directly addresses auditory disorders, and fitting of remote microphone hearing aids both assists hearing in challenging conditions and has been shown to also improve auditory skills.  

Once the hearing problems have been addressed however, language therapy is extremely important in treating the effects of the hearing problems such as deficient phonological awareness and its consequences on comprehension, spelling, vocabulary, language and literacy.  Language therapists can also treat abnormal appreciation of pitch and intonation, a common consequence of APD. These subtle aspects of speech can change a statement into a demand, a question or humour.

Does APD occur with other disorders?

Auditory Processing Disorder often occurs in conjunction with other disorders.  In particular there is considerable overlap with

  • Dyslexia
  • Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder
  • Language Impairment
  • Reading Disorder.

94% of children in a University of Auckland study with APD also had Language Impairment and/or Reading Disorder (Sharma, Purdy, Kelly 2009).