Frequently Asked Questions About APD

What is APD?

Auditory processing disorder is a generic term for hearing disorders that result from atypical processing of auditory information in the brain. Auditory processing disorder is characterised by persistent limitations in the performance of auditory activities and has significant consequences for participation.


Reference: NZ APD Guidelines 2019 and Canadian Guidelines (CISG, 2012).


The Buffalo Model definition of APD is, "what we do with what we hear." It is how efficiently and effectively people process what they hear. Our notion is that APD refers to rather basic functions of the central nervous system (CNS), but we recognize that any behavioral speech test or therapeutic procedure requires some language and cognitive knowledge. There is no clear line between where auditory processing ends and where language or higher cognitive functions begin. We do believe that understanding speech in quiet as well as in noise, dichotic listening, short-term/working auditory memory, sequencing, and sound localization are among the many functions that are heavily dependent upon auditory processing skills. We feel particularly confident in this, in part, because such difficulties respond so well to basic auditory therapies.


Reference: https://www.audiologyonline.com/articles/apd-evaluation-to-therapy-buffalo-945

How many people and what percentage of people have APD?

The prevalence of APD in children has been estimated at 2-7% in US and UK populations (Chermak & Musiek, 2007; Bamiou et al., 2001). Musiek, Gollegly, Lamb, & Lamb (1990) estimate that 3-7% of school-aged children have learning disabilities, and that a major portion of this number would also have APD. Brewer et al. (2016) state that APD prevalence in children may be approximately 10% taking into account comorbidity with other developmental disorders with which APD occurs.

What is it like to experience APD?

Auditory Processing Disorder (APD) can be confusing to understand. The best way to explain it is this: our five senses are touching, smelling, hearing, seeing, and tasting. All of my five senses work just fine. APD does have the “auditory” in it, which has to do with hearing. The processing part is my brain. My brain and ears don’t work well together, and my brain doesn’t process all the gazillion things I hear correctly. It’s like if someone is half sleeping. They can hear fine, but their brain isn’t fully on. That’s what I deal with on a daily basis, but use strategies to be successful and get around this day to day battle.


“What does Mrs. Jones mean we will be bent tomorrow?” I thought to myself.


“I don’t get it?” I asked my friend.

“We are presenting tomorrow?” she responded, laughing as she walked away after the bell.

“Oh, wow…” I thought, shaking my head.


Reference: https://dm-ed.com/news/what-it-feels-like-auditory-processing-disorder/ 

What do we think causes APD?

Some causes of APD are listed below:

hereditary developmental abnormalities


  • maturational delay

  • antenatal, perinatal and postnatal factors including prematurity and low birth weight, prenatal anoxia, prenatal exposure to cigarette smoke or alcohol, hyperbilirubinemia

  • diseases, toxins and neurological conditions affecting the brain including space-occupying lesions; Moyamoya disease and other cerebrovascular disorders; multiple sclerosis and other neurodegenerative diseases; bacterial meningitis; herpes simplex encephalitis; Landau Kleffner Syndrome and other seizure disorders; Lyme disease; metabolic disease; heavy metal exposure; solvent exposure

  • traumatic brain injury

  • blast injury

  • auditory deprivation

  • aging.

What is auditory processing disorder?

The New Zealand Audiological Society has adapted the definition of APD from the Canadian Guidelines (CISG) and states: Auditory processing disorder is a generic term for hearing disorders that result from atypical processing of auditory information in the brain. Auditory processing disorder is characterised by persistent limitations in the performance of auditory activities and has significant consequences for participation. A more simple definition by Jack Katz describes APD as “what we do with what we hear.” The prevalence of APD in the USA is estimated to be around 5% of school children and is estimated to be around 6.2% of school children in New Zealand, but is said to likely be higher in some populations, such as the aged-population. APD can have implications for academic achievement, participation, career opportunities and psychosocial development. Common symptoms of APD are similar to symptoms of hearing loss, however, the difference is that individuals with APD commonly have normal hearing. Many people with APD can hear the volume of someone speaking to them, but may not be able to accurately interpret what was said. APD is different from hearing loss in that it is not detected by standard audiometric assessments. People with APD may have normal pure tone audiometric thresholds but to refer to them as having “normal hearing”, is inaccurate. They may have a normal pure tone hearing assessment, but by definition they will demonstrate reduced hearing ability on some other measures of hearing. Research shows that auditory processing occurs at all levels of the auditory system. The term central auditory processing disorder (CAPD) is used in some documents with the intention of more precisely denoting processing in the central auditory nervous system (CANS). The abbreviated term APD is also commonly used to refer to auditory processing in the CANS. The current understanding of the auditory brain is that there is no clear boundary between central and peripheral auditory function because efferent signals from the brain modulate outer hair cell activity in the inner ear (cochlea), changing the response of the cochlea and consequently changing the afferent input from the cochlea to the brain.

Other search terms for this query:  

Is auditory processing disorder real?

What does auditory processing disorder mean?

What is central auditory processing disorder?

What does central auditory processing disorder mean?

Is central auditory processing disorder real?

Is auditory processing disorder a disability?
Is auditory processing disorder a learning disability?
Is auditory processing disorder considered a learning disability?
Can a person have auditory processing disorder and a learning disability?

The World Health Organisation (WHO) defines “disability” as “an umbrella term, covering impairments, activity limitations, and participation restrictions. An impairment is a problem in body function or structure; an activity limitation is a difficulty encountered by an individual in executing a task or action; while a participation restriction is a problem experienced by an individual in involvement in life situations. Disability is thus not just a health problem. It is a complex phenomenon, reflecting the interaction between features of a person’s body and features of the society in which he or she lives. Overcoming the difficulties faced by people with disabilities requires interventions to remove environmental and social barriers.” Individuals who have APD may experience such impairments, activity limitations, and participation restrictions. More specifically, an activity is defined as “the execution of a task or action by an individual.” Participation is defined as, “involvement in a life situation.” Activity Limitations are difficulties an individual may have in executing activities. Participation Restrictions are problems an individual may have in involvement in life situations. The Centers for Disease Control and Prevention (CDC) state that, “A disability is any condition of the body or mind (impairment) that makes it more difficult for the person with the condition to do certain activities (activity limitation) and interact with the world around them (participation restrictions).” For a person with APD, the activity limitation would be hearing difficulty and a participation restriction could entail employment, educational, and personal relationship implications. On this topic, I should mention that APD is not specifically a learning disability, however, APD may be classed as a learning disability as a consequence to having an APD diagnosis, not the primary disorder.

Other search queries for this question:

Is auditory processing disorder a learning disability?

Is auditory processing disorder considered a learning disability?

Can a person have auditory processing disorder and a learning disability?

Is auditory processing disorder genetic?
What causes auditory processing disorder?
Can auditory processing be genetic? Auditory processing disorder, is it genetic?
Can auditory processing disorder be genetic?
Auditory processing disorder causes?

There are a multitude of reasons why a person may have difficulty with auditory processing. The following image detailing such causes was derived from the New Zealand Guidelines on Auditory Processing Disorder. Some auditory processing disorders have been evidenced to have a genetic component. It is known that APD often co-occurs with other learning or developmental disabilities, which will be discussed in another segment. There also appears to be a strong correlation in the research that points to auditory deprivation secondary to otitis media (glue ear, fluid behind the eardrum) during early development in children resulting in auditory processing deficits. This makes a lot of sense, because we cannot expect children to accurately produce speech sounds and identify sound/letter correspondence if they are not hearing them correctly in the first place. Traumatic Brain Injury (TBI) is another known cause of APD. Research finds that more than 50% of adults and children who have sustained TBI have auditory processing difficulties. In addition, other causes of acquired brain injury, such as stroke, can also be associated with auditory processing deficits. Finally, research points to aging as a substantial known cause of APD due to the innate changes in the body due to the aging process, including a loss of neural synchrony.

Who can test for/diagnose APD?
How is APD diagnosed/assessed?
Auditory processing disorder how to diagnose?
Who diagnoses auditory processing disorder?
How auditory processing disorder is diagnosed?
What is an auditory processing disorder assessment? 
Who assesses auditory processing disorder?

Auditory Processing Disorder can only be assessed by an Audiologist trained in this specialty. There are many different test batteries that can be utilised to diagnose APD and although there is evidence that APD can sometimes be observed in electrophysiological studies, behavioural tests are typically used for diagnosis. Our clinic utilises the Dr. Jack Katz Central Test Battery, also known as the Buffalo Model. There are many additional ways to assess for APD and there is not currently one model that is considered superior to others currently available for clinical implementation. It is also recommended that screening measures or comprehensive assessment of cognitive and language abilities, usually by psychologists and speech-language therapists/pathologists, be completed before a diagnosis of APD is confirmed. The most commonly used diagnostic criteria state, “Diagnosis of (C)APD generally requires performance deficits on the order of at least two standard deviations below the mean on two or more tests in the battery or if poor performance is observed on only one test, the audiologist should withhold a diagnosis of (C)APD unless the client’s performance falls at least three standard deviations below the mean or when the finding is accompanied by significant functional difficulty in auditory behaviors reliant on the process assessed.”

When is auditory processing disorder diagnosed?
When can auditory processing disorder be diagnosed?

Early detection of auditory processing difficulties is recommended alongside early intervention. Most governing bodies in Audiology now encourage APD assessment below the previously recommended age of seven years using validated assessment tools developed for younger children. It has also been recommended that this assessment proceed in most cases in the presence of comorbidities and peripheral hearing loss, should the need be determined by the Audiologist, as oftentimes, meaningful findings can still be deduced about a child’s current auditory processing abilities and suitable interventions. The earlier the identification, the sooner remediation can begin. There are auditory processing assessments currently available for children down to the age of 3 years. A traditional belief is that APD assessment should not be completed until a child is 7 years of age. Reasoning behind this previously held belief include the fact that early APD tests were only normed on children down to seven years of age, due to the fact that maturation of the CANS does not take place until young adulthood, and due to inter-subject variability in young children. At the current time, it is recommended that APD diagnosis in children below the age range at which a complete test battery is possible, or children not capable of completing age-appropriate tests due to comorbidities, can be diagnosed as being “at risk for”, “provisional”, or “criteria for diagnosis not met but auditory skill deficits are evident”. Regardless, intervention should not be delayed and may take place upon obtaining information regarding a child’s auditory processing abilities even without a formal diagnosis. It should be noted that in this case, a follow-up appointment should still take place at a later date for more comprehensive and definitive testing as the child matures.

Who can treat APD? Can APD be cured? How is APD treated? Who treats auditory processing disorder? Can auditory processing disorder go away? Does APD go away?

APD can be treated by providing therapy and there are many resources to support these individuals. Audiologists and speech-language pathologists are health professionals with the scope of practice to provide these services. Recommendations for managing APD consist of multiple facets including direct treatment, other referrals, and additional information and support. In regard to the treatment aspect of APD, there are many therapy programs currently available in-person or online. It will depend on the age of the individual, among other factors and diagnosis that determine which programs would be most appropriate for the individual. Devices, such as amplification or personal FM/RMHA devices are also sometimes prescribed in conjunction with direct therapy.  Treatment via amplification devices (FM system, hearing aids) must occur via the audiologist, however, direct treatment sessions, including auditory and phonemic training, may take place with an audiologist and/or speech-language pathologist. Referrals may also be made to other professionals depending on the presenting complaints of the individual, such as speech-language pathology, optometry, psychology, paediatrics, as well as others. In addition, information such as strategies to implement in the classroom at home, and strategies to provide to coaches, alongside information for support groups can be equally beneficial to individuals with APD and their families. Generally speaking, via neuroplasticity, auditory processing can be permanently improved with the appropriate intervention. Studies have shown that treatment is largely possible at any age, however, treatment can be slowed or limited by comorbid conditions, and it appears the earlier intervention is initiated, the better these individuals often fare.

Is auditory processing disorder a form of autism? Is auditory processing disorder autism? Can it coincide with Autism? Can auditory processing disorder be confused with other conditions? Are APD and dyslexia related? Are auditory processing disorder and dyslexia related?

APD is not a form of Autism, however, APD can coexist with other learning or developmental disabilities. The current recommendation for children currently diagnosed with ASD, ADD, ADHD, dyslexia, visual processing disorder, children with a history of middle ear dysfunction (i.e., ear infections, glue ear), and language disorder, among others, is to consider APD evaluation if listening concerns are present. Interestingly, “due to overlap of sensory systems in the brain” (AAA, 2010, pp. 6-7), it is commonly found that individuals with APD are more likely to also be diagnosed with visual processing disorder. Relative to ASD, the current research reveals auditory processing weaknesses in individuals diagnosed with ASD are more pronounced for complex auditory signals, such as speech (O’Connor, 2012). For individuals diagnosed with dyslexia and/or a speech, language, and reading impairment, research indicates it is likely these individuals will also show auditory processing difficulties due to an underlying phonological processing weakness and demonstrative difficulty with the discrimination of speech sounds (Sharma et al., 2009).  Due to the common occurrence of APD weaknesses identified alongside other diagnosis, it can at times be difficult to tease out one weakness from another. However, with this information in mind, oftentimes, useful information can be gleaned by performing APD assessment in order to determine appropriate treatment and environmental recommendations. It has previously been recommended that such assessment not be performed due to this difficulty, however, this prevents individuals from access to interventions that may have significantly improved quality of life. For example, if a person experiences difficulty hearing in noise due to APD, ADD, ADHD, Autism, etc., all children will likely benefit from treatment to address this area of concern no matter the root source. For some children, providing additional breaks during assessment may be beneficial in order to obtain results that are demonstrative of their auditory abilities at their peak performance. The findings of such assessment will certainly yield some useful information. For example, if a child with a co-existing diagnosis passed all components of the assessment, even with breaks between items, this would be consistent with no auditory processing weaknesses, whereas if a child struggled significantly in all areas of the assessment, this may indicate auditory processing weaknesses alongside a more primary learning or developmental difficulty. In some instances, complete test batteries may not be able to be obtained, however, it is likely that some useful information would have been gleaned. For individuals with a language or cognitive impairment, assessments may be chosen that correspond to their cognitive age equivalency. In the event there are some gaps that are unable to be filled during assessment, recommending auditory intervention would not harm a child, and if anything, would likely bolster learnings. For example, there is research that demonstrates benefits gained from RMHA systems for children with a variety of diagnosis, such as ADHD, APD, ASD, and dyslexia, among others. Of course, working alongside other professionals to make recommendations for each individual child/individual will be paramount.

Can APD be diagnosed if a person has already been diagnosed with hearing loss?

By default, a person with any form of hearing loss (i.e., sensorineural mixed, conductive hearing loss) will have auditory processing weaknesses, as they are not hearing the speech signal within normal limits. Conductive hearing losses are more common in children due to middle ear infections and sensorineural hearing losses are more common in adults due to noise exposure and the typical changes with aging processes. However, in light of previously diagnosed hearing loss, oftentimes useful information can be gleaned from auditory processing assessment, especially with mild and/or symmetrical forms of hearing loss due to greater ease in making assessment alterations. For some individuals, hearing aids, if recommended, may not significantly improve the individual’s ability to interpret speech signals. In instances where this hearing loss is not severe-profound (wherein other recommendations may be made, such as cochlear implantation), auditory processing should be investigated. The presentation level of auditory processing assessments can be altered to ensure a comfortable listening level for individuals with hearing loss, although such alternation should be noted. For these individuals, APD can be ruled out with passing results. For individuals with a unilateral hearing loss whose results yield weaknesses in the good ear, such findings are consistent with APD. Similarly, if weaknesses are identified in one ear for an individual with a symmetrical hearing loss, these findings will also likely to be consistent with APD. However, if there is no clear pattern of weakness on APD assessment, this could potentially be put down to the influence of hearing loss. However, in this instance, although it would be up to the discretion of the audiologist to withhold or provide an APD diagnosis, therapy should still be considered, as this can only be of benefit to the individual. Likewise, obtaining as much information as possible about how the individual is processing auditory information will be useful to provide recommendations for the educational, home, and social settings to assist in providing appropriate recommendations to most benefit the individual. For individuals who have severe-profound hearing loss or who utilize a cochlear implant, auditory training exercises often recommended for individuals diagnosed with APD will often be highly beneficial as a form of aural re(habilitation).

Can auditory processing disorder get worse?

Generally speaking, due to neuroplasticity, auditory training and amplification often results in permanent improvement in auditory processing. However, there are a number of reasons why the processing abilities of a person might decline and/or an auditory processing difficulty may be later acquired. As mentioned previously, in relation to known causes of auditory processing disorder, research on Traumatic Brain Injury (TBI) finds that more than 50% of adults and children who have sustained TBI have auditory processing difficulties. In addition, other causes of acquired brain injury, such as stroke, can also be associated with auditory processing deficits. Finally, research points to aging as a substantial known cause of APD due to the innate changes in the body due to the aging process, including a loss of neural synchrony. So, put simply, if someone had completed auditory training and an improvement had been documented, it is unlikely that this improvement would worsen unless an injury of some sort took place and/or over a greater length of time the aging process may have some sort of effect on a person's processing abilities.

How does auditory processing disorder affect reading, writing, learning? How auditory processing disorder affects learning?

It is not always possible to identify what came first, the chicken or the egg, however, generally speaking, reading, writing, spelling, and learning, among others, can be secondary difficulties associated with APD. Such difficulties are often signs that a person could be struggling with auditory processing, especially if a person struggles with listening tasks more so than other learning modalities. If a person has difficulty distinguishing differences between similar speech sounds and associating a speech sound with its letter name, which is associated with auditory processing, then it is understandable they may struggle to read, write, or spell. This basic ability, phonological awareness, can be assessed and treated. In relation to learning, individuals with APD often require repetition of spoken-information, which can have implications for their ability to retain learned information and may therefore have an effect on classroom performance. These individuals may face criticism from peers, teachers, and/or family members who may be unaware of the difficulty they may be facing. This can lead to behavior problems in such environments and sometimes lowered self-esteem. For children with APD, the classroom environment can be especially challenging depending on the number of students in the classroom and the noise level. Research shows that a signal to noise ratio (SNR) of at least +15dB between the voice of the teacher and background noise in the classroom is needed for typically developing children (ASHA, Guidelines for fitting and monitoring FM systems. 2002). Due to the high levels of noise in modern day classrooms, especially in open-plan classrooms, this can be challenging to meet making these environments difficult for typically developing children, let alone children who have been diagnosed with APD who may struggle more so to hear in noise. It should be noted that, as previously mentioned, APD can coexist with other learning or developmental disabilities. The current recommendation for children currently diagnosed with ASD, ADD, ADHD, dyslexia, visual processing disorder, children with a history of middle ear dysfunction (i.e., ear infections, glue ear), and language disorder, among others, is to consider APD evaluation if listening concerns are present.

Does auditory processing disorder affect speech?

Speech and language delays may be a secondary difficulty associated with APD. Research by Sharma et al., report approximately 47% of children diagnosed with APD have co-occuring language and reading difficulties, however due to common research formats utilized (i.e., cross-sectional), it is difficult to determine if APD is the root cause of this difficulty or if there is something else that can account for such difficulty (2009). There is also some reason to believe that longstanding otitis media (glue ear/ear infection) may lead to auditory deprivation by way of conductive hearing loss, especially in the early critical development period, that can result in APD and speech-language difficulties.

What does APD look like?

There are no physical characteristics to report in relation to APD, as APD relates to the hearing sense. However, individuals who have been diagnosed with APD may appear to struggle to hear in background noise, may appear to be confused upon mishearing spoken information, and may appear fatigued more so than their peers following a long day at school or work.

What does APD sound like?

There is no specific speech pattern to report in relation to APD, as APD relates to the hearing sense. However, a person may ask for repetition, say “what?”, “huh?”, or “pardon?”, may ask you to speak in a clear manner and/or may ask you to face them when you are speaking to ensure good communication.

How does APD affect adults? How does this compare to children with APD? What is auditory processing disorder in adults? How does auditory processing disorder affect adults?

Many things regarding difficulties with APD amongst children and adults remain the same, such as: requiring repetition of spoken information, difficulty following multiple-step instructions, difficulty hearing speech in noise, taking longer to respond to a verbal query, saying, “what?” or “huh?” often, trouble understanding humor, and listening fatigue, among others. For children with APD, the classroom environment can be especially challenging depending on the number of students in the classroom and the noise level. Research shows that a signal to noise ratio (SNR) of at least +15dB between the voice of the teacher and background noise in the classroom is needed for typically developing children (ASHA, Guidelines for fitting and monitoring FM systems. 2002). Due to the high levels of noise in modern day classrooms, especially in open-plan classrooms, this can be challenging to meet making these environments difficult for typically developing children, let alone children who have been diagnosed with APD who may struggle more so to hear in noise. For adults, hearing in the workplace, such as in meetings and following verbal instructions may be challenged. It is recommended that APD assessment for adults be considered when pure tone results are normal, but listening difficulties are reported, as well as adults with a diagnosed peripheral hearing loss who do not notice a substantial improvement through the use of hearing aids and/or adults who report difficulties disproportionate to their audiogram. There is evidence that adults with otherwise normal pure tone peripheral hearing who have been diagnosed with APD may see benefit from hearing aids alone or from hearing aids in conjunction with an accessory remote microphone. In comparison to children who commonly utilize personal FM systems, hearing aids are more commonly recommended for adults, due to differences in the listening situations such devices would be utilised for (classroom vs. one-on-one conversations). In addition, it has been evidenced that adults do not require as large of a signal to noise ratio (SNR) in comparison to that required by children.

What is the history of APD? Who discovered APD? When was APD discovered?

APD has been known and researched for over 50 years. In 1954 several medical papers were published that first described APD assessment. The use of dichotic listening to test for APD was first described in 1956. Since this time, much has taken place in relation to the development of APD test batteries and treatment programs and many guidelines by audiology and speech-language pathology/therapy professional organizations have been put into place.

 

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