Auditory processing disorder

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ICD9 = ICD9|388.4, ICD9|389.9, ICD9|389.12, or ICD9|389.14
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MeshID = D001308

Auditory Processing Disorder (APD) (previously known as "Central Auditory Processing Disorder" (CAPD)) is a disorder in the way auditory information is processed in the brain. It is not a sensory (inner ear) hearing impairment; individuals with APD usually have normal peripheral hearing ability. APD is an umbrella term that describes a variety of problems with the brain that can interfere with processing auditory information.

Definitions

The American Speech-Language-Hearing Association (ASHA) published their first definitive Technical Report "(Central) Auditory Processing Disorders" in January 2005" as an update to the "Central Auditory Processing: Current Status of Research and Implications for Clinical Practice (ASHA, 1996)" [cite web
title = Central Auditory Processing: Current Status of Research and Implications for Clinical Practice. Technical Report, (1996)
work = Working Group on Auditory Processing Disorders
publisher = American Speech-Language-Hearing Association
url = http://www.asha.org/docs/html/TR1996-00241.html
accessdate = ] , and complements the UK's "Medical Research Council's Institute of Hearing Research's" "Auditory Processing Disorder (APD) pamphlet, Oct 2004" [cite web
title = Auditory Processing Disorder (APD). Pamphlet, (2004).
work = British Society of Audiology APD Special Interest Group
publisher = MRC Institute of Hearing Research
url = http://www.ihr.mrc.ac.uk/downloads/research/apd/apd_booklet.pdf
accessdate = 2008-01-15 ] .

Auditory processing disorder can be a congenital or an acquired condition (for example; resulting from ear infections and head injuries) which refers to difficulties in the processing of auditory information within the central nervous system, such as problems with: "...sound localization and lateralization; auditory discrimination; auditory pattern recognition; temporal aspects of audition, including temporal integration, temporal discrimination (e.g., temporal gap detection), temporal ordering, and temporal masking; auditory performance in competing acoustic signals (including dichotic listening); and auditory performance with degraded acoustic signals." "(Quote from: (Central) Auditory Processing Disorders, Technical Report, Jan 2005)"

It is recommended, and in some areas a legal requirement that Auditory Processing Disorder is assessed and diagnosed by an Audiologist. (Better still, an Assessment Team comprised of an Audiologist, a Speech and language Pathologist, and an Educational Psychologist) [ http://www.infolinks.apduk.org/international_page.htm from where you can still download a copy of Arkansas Department of Education GUIDELINES FOR DETERMINING A CENTRAL AUDITORY PROCESSING DISORDER ]

The Committee of UK Medical Professionals Steering the UK Auditory Processing Disorder Research Program have developed the following working definition of Auditory Processing Disorder

"APD results from impaired neural function and is characterized by poor recognition, discrimination, separation, grouping, localization, or ordering of non-speech sounds.It does not solely result from a deficit in general attention, language or other cognitive processes." [http://www.thebsa.org.uk/apd/Home.htm The British Society of Audiology and the UK APD Steering Group ]

Diagnosis

APD is recognized as a major cause of dyslexia [ [http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=retrieve&db=pubmed&list_uids=12114001&dopt=Abstract Disruption of posterior brain systems for reading in children with developmental dyslexia.] Biol Psychiatry 2002; 52: Shaywitz BA, Shaywitz SE, Pugh KR, Mencl WE, Fulbright RK, Skudlarski P, et al.] . As APD is one of the more difficult information processing disorders to detect and diagnose, it may sometimes be misdiagnosed as ADD/ADHD, Asperger and other forms of autism, but it may also be a comorbid aspect of those conditions if it is considered a significant part of the overall diagnostic picture. APD shares common symptoms in areas of overlap such that professionals who were not aware of APD would diagnose the disabilities as those which they were aware of. APD can also be confused with Language Processing Disorder. Unlike APD, LPD is more specifically a problem associated with the linking of words, both written and spoken, to semantics (meaning) and someone can have both APD and LPD. Unlike those with LPD, those with APD can usually get the meaning of language from written words where those with LPD show problems with both heard and read words, demonstrating that the basic issue is not an auditory one.

People with APD intermittently experience an inability to process verbal information. When people with APD have a processing failure, they do not process what is being said to them. They may be able to repeat the words back word for word, but the meaning of the message is lost. Simply repeating the instruction is of no use if a person with APD is not processing. Neither will increasing the volume help.

People with APD have a disorder processing auditory information "within" the brain. The written word is a visual notation of verbal language, thus Auditory Processing Disorder can extend into reading and writing. As a consequence, APD has been recognised as one of the major causes of dyslexia.

There are also many other hidden implications, which are not always apparent even to the person with the disability. For example, because people with APD are used to guessing to fill in the processing gaps, they may not even be aware that they have misunderstood something.

Causes

There are many possible causes of APD. For many APD can be inherited as part of their Genetic make up. APD can be acquired especially via severe Ear Infections such as Otitis Media with effusion (Glue Ear).APD can also be acquired due to an accident that causes head trauma or by lead poisoning. Adults of advancing years can also acquire APD as their information processing faculties reduce as part of the ageing process. Because there are many different possibilities, each person must be assessed individually.

Characteristics

Persons with CAPD often:
* have trouble paying attention to and remembering information presented orally; cope better with visually acquired information
* may have trouble paying attention and remembering information when information is simultaneously presented in multiple modalities
* have problems carrying out multi-step directions given orally; need to hear only one direction at a time
* appear to have poor listening skills, and need people to speak slowly
* need more time to process information.
* develop a dislike for locations with background noise such as bar, clubs or other social locations
* prefer written communication (e.g. text chat)It appears to others as a problem with listening. Somebody with APD may be accused of "not listening".
* have behavioral problems.

APD can manifest as problems determining the direction of sounds, difficulty perceiving differences between speech sounds and the sequencing of these sounds into meaningful words, confusing similar sounds such as "hat" with "bat", "there" with "where", etc. Fewer words may be perceived than were actually said, as there can be problems detecting the gaps between words, creating the sense that someone is speaking unfamiliar or nonsense words. Problems relating what has been said with its meaning, despite obvious recognition that a word has been said, as well as repetition of the word. Separating speech sounds from background noise, pink sound, such as the sound of a radio, television or a noisy bar, it can be difficult to impossible to understand speech, depending on the severity of the auditory processing disorder. Using a telephone can be problematic, due to low quality audio, poor signal, intermittent sounds and the chopping of words can be a problem for someone with Auditory processing disorder to cope with, in comparison with someone with normal auditory processing. [cite web
title = (Central) Auditory Processing Disorders. Technical Report, (2005).
work = Working Group on Auditory Processing Disorders.
publisher = American Speech-Language-Hearing Association.
url = http://www.asha.org/docs/html/TR2005-00043.html
accessdate = ] Many who have auditory processing disorder subconsciously develop visual coping strategies, such as lip reading, reading body language, and eye contact, to compensate for their auditory deficit, and these coping strategies are not available when using a telephone.

econdary characteristics

Those who have APD tend to be quiet or shy, even withdrawn from mainstream society due their communication problems, and the lack of understanding of these problems by their peers.

One who fails to process any part of the communication of others may be unable to comprehend what is being communicated. This has some obvious social and educational implication, which can cause a lack of understanding from others. In adults this can lead to persistent interpersonal relationship problems.

Some of these symptoms can be shared with other related disorders which can also have areas of overlap, such as acquired brain injury, attention deficits, dyslexia or learning difficulties, hearing loss, and psychologically-based behavioral problems.

APD may be related to cluttering [William O. Haynes, Rebekah Hand Pindzola, Michael J. Moran, Communication Disorders in the Classroom: An Introduction for Professionals in School Settings, ISBN 0763727431, Jones & BartlettPublishers (2006), p. 251] , a fluency disorder marked by word and phrase repetitions.

Treatment

Remediations and training

There are no research supported treatments for APD available, however a variety of treatments have been offered commercially in the absence of solid empirical research support for their efficacy.

* [http://resources.apduk.org/manage_apd.htm Management of Auditory Processing Disorders] is taken from the notes provided at a presentation by Dr. Dilys Treharne as part of her UK NHS fund APD Research program.
* [http://www.aitinstitute.org AIT Institute for Auditory Integration Training] . Free resources, information and referrals to AIT Practitioners worldwide.
* Lindamood-Bell Learning Processes (particularly, the Visualizing and Verbalizing program)
* Physical activities which require frequent crossing of the midline (e.g. occupational therapy)
* Sound Field Amplification

Relation to Language Processing Disorder

APD can be distinguished from Verbal Agnosia or Language Processing Disorder.Those with APD have auditory difficulty distinguishing sounds including speech from extraneous sounds, e.g. fans or other chatter. APD is purely about processing what you hear both verbal and non-verbal. For those who have APD processing language although a problems is only one of many symptomsAPD can be one of many issues that could contribute to, or be an underlying cause of a Language Processing Disorder. Those who have a Language Processing Disorder will struggle to access the meaning to both verbal language and its visual notation, the written word, and require non-verbal help to match their stronger learning styles and skills. Which may require more visual aides such as pictures and diagrams, the use of body language, and other alternative forms of communication to work around their problems accessing these man made communication systems. [ [http://learningdisabilities.about.com/od/learningdisabilitybasics/p/rsptvlangdsrdr.htm Learning Disabilities in Receptive Language - Disabilities in Listening Comprehension] ] [ [http://www.soundidears.com/aud_process_differ.html Differentiating a language processing disorder (LPD) from an APD] ] .

APD has been seen as one of many underlying causes of many Developmental Language Disorders such as Dyslexia and Autism. [http://apd.apduk.org/rosalie_seymour.htm Central Auditory Processing Disorders as a key factor in Developmental Language Disorders ] [http://www.audiologyonline.com/articles/article_detail.asp?article_id=725 Temporal Processing Deficits in Children with Dyslexia] [http://www.ingentaconnect.com/search/expand?pub=infobike://jws/dys/2004/00000010/00000003/art00005 Auditory processing skills and phonological representation in Dyslexic children]

Epidemiology

APD is thought to affect 5% of school-aged children. [ [http://kidshealth.org/parent/medical/ears/central_auditory.html Auditory Processing Disorder] ]

ee also

*Pure Word Deafness
*Asperger syndrome
*Attention-Deficit Hyperactivity Disorder

References

External links

*
* [http://www.aitinstitute.org Auditory Integration Training Institute]
* [http://www.neuron-learning.co.uk Neuron Learning suppliers of Fast ForWord family of programmes]
* [http://www.learningrx.com/central-auditory-processing-disorder.htm A Cognitive Approach]
* [http://www.filteredsoundtraining.net Filtered Sound Training]

[Category:Auditory Processing]