We don't hear with our ears alone. Hearing also involves the brain.

What is Auditory Processing Disorder (APD)?

Auditory processing disorder (APD), sometimes referred to as central auditory processing disorder (CAPD), is a general term for hearing disorders in which the ears process sound normally but the hearing centres and circuits of the brain don’t always process incoming information sufficiently quickly or accurately. Children with APD can hear but they sometimes have trouble understanding what they hear.

APD in Children

It is estimated that 1 in 20 children may have difficulties that affect processing of auditory information in the brain. APD can affect understanding, especially in challenging listening situations such as in the presence of other distracting sound, or when listening to complex information, for example, instructions. APD is an under-recognised hearing problem that is an underlying cause of learning difficulties in many children. APD is not detected by standard hearing tests but it can be diagnosed with special hearing tests. Most importantly, there are proven helpful treatments.


Children with APD can hear but they sometimes have trouble understanding what they hear.

APD Symptoms

If one or more of the following hearing or listening problems are present, and standard hearing test results are normal, APD may be the cause.

  • difficulty following spoken directions unless they are brief and simple
  • difficulty attending to and remembering spoken information
  • slowness in processing spoken information
  • difficulty understanding in the presence of other sounds
  • being overwhelmed by complex or “busy” auditory environments e.g. classrooms, shopping malls
  • undue sensitivity to loud sounds or noise
  • poor listening skills
  • preference for loud television volume
  • insensitivity to tone of voice or other nuances of speech
How does it sound to have APD?

Adults with APD, particularly if it arose in adulthood so they have prior experience of good hearing, can provide insight into the experience of hearing with APD.

Dr Louise Carroll QSO, JP, GDPPA , MPM, previously Chief Executive Officer of the National Foundation for Deaf and Hard of Hearing has Auditory Processing Disorder and uses hearing aids and a remote microphone (RM) system. She describes her hearing experience as follows.

“Without my hearing aids or RM 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 RM 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 child with APD when first fitted with a remote microphone hearing aid system 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.

Listen to an Audio Simulation of APD:

Causes of APD

A number of factors can affect the normal development of auditory processing skills. Causes of APD include hereditary, developmental and birth-related factors, brain injury and neurological disorders. There is also research evidence that suggests that prolonged middle ear disease (e.g., glue ear) can result in APD, if hearing is disrupted during important developmental periods in infancy or early childhood.

APD and Associated Conditions

APD frequently occurs in conjunction with other conditions or disorders including in particular dyslexia, autism spectrum disorder (ASD), and developmental language disorder (DLD). APD sometimes co-occurs with attention disorders (ADD and ADHD). Because APD can affect the correct and rapid recognition of phonemes, the sounds of speech, it can be an underlying cause of language, phonological awareness, spelling, and reading problems including dyslexia.

Conditions commonly associated with APD include:

  • brain injury
  • neurological disorders affecting the brain
  • history of frequent or persistent middle ear disease (otitis media, ‘glue ear’)
  • difficulty with reading or spelling
  • dyslexia
  • autism spectrum disorder
  • language disorder or delay.
Effects of APD on Children

Children with APD often miss, or misunderstand, what is said. This can be because they miss parts of speech that are too fast or too complex, or because hearing against any background noise is especially difficult for them. Children need to develop hearing skills to separate important sounds from other surrounding sounds, such as the teacher’s voice against other children moving and talking. They also need to learn to rapidly and correctly identify all the sounds (phonemes) that make up language, no matter the voice or speed or accent with which they are spoken, and be able to correctly distinguish between subtly different speech sounds. Children with APD often have difficulty in always rapidly and correctly identifying every phoneme in spoken language. Children with APD may also have poor skills at detecting nuances of speech denoted by changes in pitch or emphasis which, for example, may indicate emotion or humour or change a statement into a question. The communication problems caused by APD can lead to low confidence and self-esteem, and difficulties with socialisation.


The effects of APD on children and adults were clearly outlined in a Government report into APD services in New Zealand in 2014. Following are some of the comments by adults with APD and parents of children with APD included in the report.

  • “She just sat in the toilets at school all day crying. The teachers said it was bad behaviour.”
  • “He sits a lot with his hands over his ears in class.”
  • “The worst thing was he lost all his confidence and friends. The best thing we did was take him out of school. For all those years he thought he was dumb. It took ages for him to get his confidence and self-esteem back.”
  • “Throughout school I thought I was “stupid” Why? Because that’s what “school” told me, my academic achievements at school were very poor but not through lack of trying (just like my daughter) I’m sorry to say even some of my teachers told me I’d never succeed. I now realise this was in part because I could not understand what was being said to me in the classroom. Let me explain further - I can only focus on the first piece of information someone tells me, I can’t listen and write things down at the same time – still to this day I can’t…”

(Auditory processing disorder: New Zealand review. Esplin and Wright, 2014).
Ministry of Health: Report on APD services in NZ

APD and Learning

APD is frequently a barrier to meeting academic potential. Many children with APD will struggle with language and literacy skills, and overall academic progress. Some children with APD may be meeting expectation for their age and year level, yet are not meeting their own potential.

When listening is a challenge, learning is more difficult. Children with APD may under-achieve in school despite great effort.

Because listening is difficult, they may also become less attentive, they may become more anxious and frustrated with their learning. As a result they may become withdrawn or perhaps behaviour becomes a problem. The extra effort required for listening often results in children with APD being exhausted at the end of the school day.

Diagnosis of APD in Children

APD can only be diagnosed by an audiologist. Many hearing clinics and audiology services provide general hearing tests and fit hearing aids but not all provide APD services. At SoundSkills APD Clinic we provide an audiology service that specialises in auditory processing disorder diagnosis and auditory processing disorder treatment. We diagnose APD using specialised hearing tests (APD tests) that evaluate ability to listen in noise, ability to use both ears together, ability to detect subtle changes in sounds, and auditory memory skills. Most tests of auditory processing require a response from the child. We tailor our assessments to meet the individual child’s needs. All our auditory processing disorder tests are age appropriate and we consider the limitations associated with other conditions that the child may have.

At SoundSkills APD Clinic we tailor our assessments to meet the individual child’s ability level.

So that we can make good decisions on how to best assess for APD and interpret our test results, we include assessment of cognitive and language ability as well as standard hearing tests. We also collect information about auditory skills and listening behaviours through questionnaires completed by the child’s teacher and parents.

A number of factors affect the age at which an APD diagnosis can be made with certainty. As with any aspect of child development, hearing skills mature as children grow and more sophisticated tests become possible. Current tests allow us to make definitive diagnoses from the age of six years old, but considerable information about auditory processing skills can be measured at age five and some APD symptoms can be verified at age four. While a formal APD diagnosis is not usually made under the age of 6 years old, we accept referrals from four years of age since, for children who are clearly experiencing hearing difficulties, it’s best for the child to start age-appropriate interventions as early as possible.

Treatment of APD in Children

Auditory processing disorder is usually very treatable because the hearing dysfunction is in the brain. With training, the brain is able to learn new skills and develop strengthened or new neural pathways. This is called neuroplasticity. Because of neuroplasticity, auditory skills can be improved. With treatment many children will improve their hearing ability sufficiently to enable them to no longer be handicapped by APD. Progress depends on a number of factors. The presence of other medical or developmental conditions for example may limit ultimate achievement.

APD treatment requires a team approach. Successful intervention and management of APD occurs when a team of professionals work together to provide treatment and support. At SoundSkills APD Clinic we provide a specialist team of audiologists, a speech language consultant, Education Advisers and an Adviser on autism spectrum disorder (ASD) to contribute to treatment. Our Education Advisers also go into a child’s school and work with the child, teacher and parents. We also collaborate as required with other specialists outside of SoundSkills such as educational psychologists, paediatricians, occupational therapists, ENT Specialists and teachers.

There are three main components to treatment of APD:

  • auditory training to correct hearing weaknesses such as amblyaudia (one-sided hearing weakness),
  • fitting of assistive hearing technology to assist hearing and ultimately improve hearing abilities over time, and
  • language therapy including phonological awareness training.
Auditory Skills Training

Some auditory processing deficits can be improved by auditory training. This can be in-clinic therapy or at home training and includes deficit-specific treatment such as ARIA (Auditory Rehabilitation for Interaural Asymmetry) therapy, and computer-based programmes. There are many auditory training software apps and programmes promoted as home-based treatments for APD but not all have been proven effective in scientific trials. Specific auditory software can be effective when chosen as part of a comprehensive treatment plan. Follow your audiologist’s advice on which auditory training programmes are both evidence-based and appropriate for your child.

There is evidence that listening to mildly amplified speech through audiobook listening is beneficial for children. We recommend books that engage and maintain a child's attention be used so that the child is actively engaged in the listening process. Specific advice on listening mode, level, duration, and type of audiobook is provided when audiobook listening is included in a SoundSkills APD treatment plan.

Learning a musical instrument (including singing coaching) is also beneficial for auditory processing skills.

Remote Microphone Hearing Aid (RMHA) Systems

Remote microphone hearing aid (RMHA) systems consist of small hearing aids worn by the child and a small transmitter microphone worn by the speaker (for example; parent, teacher, coach, friend). The remote microphone transmits the speaker’s voice direct into the hearing aids. RMHA systems (previously referred to as FM systems) have a double effect. RMHA systems assist children to hear while at the same time stimulating neuroplastic changes in the brain leading to long term improvement in hearing ability.

RMHA systems greatly improve the ability of children with APD to hear, learn and participate in multiple life situations. Benefits that have been verified in research studies include improved classroom attention and participation, academic achievement, phonological awareness, reading and social development. Improvements in confidence and self-esteem are seen, and children are less fatigued after school.

Long Term Benefits of Using RMHA Systems

The mild amplification provided by remote microphone hearing aid systems stimulates auditory pathways and centres in the brain. Through neuroplasticity and a process called synaptogenesis new connections can be made and pathways strengthened. Research shows multiple hearing benefits, seen as improved hearing skills (measured when not wearing RMHA systems), over time in children with APD or dyslexia as a result of having worn RMHA systems. Some of these beneficial neuroplastic changes are observable in recordings of brain waves in response to sounds. This therapeutic effect of using RMHA systems means that children may not need hearing assistance long term. On average two to three years of use is common but individual cases vary markedly.

Hearing in School

Classrooms can be difficult listening environments. With the move to large innovative learning environments (ILEs) with many children and multiple teachers in the same acoustic space, children are faced with special hearing challenges including an increase in classroom noise, longer listening distances and multiple learning positions. Studies show that classroom noise levels sometimes exceed 70 decibels (dBA), the level of a vacuum cleaner in a house, or a roadside with passing traffic. In a New Zealand study Park (2018) measured 75dBA in an ILE. RMHA systems assist children to hear and learn by amplifying the teacher’s voice to a level that is clear, safe and consistent no matter where the child is, or what the background noise level is like.

School Guidance

For children, optimising the learning environment is critical. When remote microphone hearing aid systems are trialled in school it is important to have an expert involved at the school to assist the child, teacher and parents with the trial and to ensure the hearing system is used optimally. The SoundSkills team includes Education Advisers, experienced in special education, who work on site with the school’s Special Education Needs Coordinator (SENCo), the teacher and any other education staff who are involved, as well as with the child and parents. They facilitate introduction of remote microphone hearing aid systems, help set up the trial, carry out classroom observation of the child to ascertain the difficulties the child encounters, provide guidance on communication and teaching strategy, and assist with Individual Education Plans.

Treating Phonological and Language Problems

Children with APD often have deficient phonemic perception, that is, they may not recognise or be able to differentiate all of the sounds of language quickly and correctly under all listening conditions. This leads to weaknesses in phonological awareness, the ability to recognise and manipulate the sounds which make up spoken language. Poor phonological awareness often underlies poor spelling, poor vocabulary, reading and language disorders, and dyslexia. A speech language therapist can assess the areas of deficiency and implement a therapy programme to address them. While phonological and language therapy does not directly address the underlying hearing problem as do auditory training therapy and the use of remote microphone hearing aid systems, it addresses the consequences of the poor hearing and as such is an integral part of the management of APD.

Treatments not Supported by Scientific Evidence

Some alternative treatments promoted for APD lack a plausible scientific basis and/or a solid body of peer-reviewed evidence of efficacy published in reputable scientific journals. In particular professional audiology and speech-language organisations warn that franchised systems based on listening to processed music, sometimes utilising bone conduction rather than air conduction, should not be recommended or used by their members. In the same way that watching sport doesn’t improve fitness, research shows that passive listening to music does not improve auditory processing skills. On the other hand active engagement in learning music is excellent for auditory skills.

Further Information and Support

The first thing a family requires if their child receives an APD diagnosis is information. Just understanding the cause of their child’s difficulties can be helpful to both parents and the child. Next, they need to know simple strategies on how to communicate effectively. From there information about treatment is required. As much information as possible is provided in individual consultations, but SoundSkills’ free seminars on APD are very helpful to parents wanting to learn more about APD. Apart from the seminar with audio demonstrations and ample time for questions, parents can also learn from the experiences of others in the audience.

Hearing Technology Funding

The Ministry of Health provides free hearing aids for children with other causes of hearing loss, but specifically excludes hearing loss due to APD. The Ministry of Education provides remote microphone hearing aid (RMHA) systems for high needs school age children diagnosed with APD who meet specific eligibility criteria. SoundSkills assists clients to determine whether they might qualify for a Ministry of Education assistive hearing technology trial.

The Ministry of Education fitting service is variable across New Zealand; some children are provided equipment directly from their school, whereas some other children have their hearing systems fitted by an audiologist.

SoundSkills can provide a fitting service for Ministry of Education funded RMHA systems on request. Hearing technology should always be fitted and verified by an audiologist. Fitting by an audiologist avoids such problems as incorrect volume settings, unbalanced settings between left and right ears, problems with physical fit, and fitting when there are contraindications that can only be identified by examination of the ear.

In accordance with the New Zealand Guidelines on Auditory Processing Disorder we recommend that RMHA systems are fitted by an audiologist to ensure that the physical fit and the sound are set correctly for the individual child.

In the absence of public funding parents can purchase RMHA systems privately from SoundSkills. As a lower cost option manufacturer-refurbished systems are sometimes available. SoundSkills offers a comprehensive service involving selection of a suitable solution, audiological fitting, a trial period of several weeks, and assistance throughout the trial period from one of our Education Advisers who will work with the family and school to carry out an effective trial with classroom observation and measurable goals and assist in reaching a decision on whether to proceed with the selected hearing equipment.

Children with APD who also have a hearing loss evident in a standard hearing test may be eligible for funding from the Hearing Aid Funding Scheme (HAFS) provided by the Ministry of Health. The HAFS covers the cost of hearing aids but not the cost of the fitting service.

When APD is associated with injury, the Accident Compensation Corporation (ACC) may cover the cost of assessment and recommended treatment including RMHA systems, auditory training and language therapy.


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