Diagnosis, Treatment, and Management of Children and Adults with Central Auditory Processing Disorder
American Academy of Audiology. (2010).
Reston (VA): American Academy of Audiology, 3-51.
This guideline provides recommendations for the diagnosis, treatment and management of children (age 7 and above) and adults with (central) auditory processing disorders. The guideline includes recommendations for case history, screening, diagnosis, intervention, and education and training for audiologists.
American Academy of Audiology
Intervention for central auditory processing disorders should be initiated "as soon as evidence is obtained from behavioral and/or electrophysiologic measures demonstrating [central auditory nervous system] CANS involvement that results in a diagnosis of (C)APD" (p. 23). Individuals experiencing communicative or academic difficulty should receive intervention provided by a multidisciplinary team and requires collaboration with related professionals such as physicians, speech-language pathologists, and neurologists (Class 5 Evidence).
"In addition to commercially available tests, audiologists can create, manipulate and record verbal and non-verbal stimuli using a number of software programs.... [These tools] should not be used for diagnostic purposes until sufficient research has been conducted establishing their efficiency and clinical utility" (p. 19).
"Effective intervention should be evidence-based and individualized" (p. 25) based on assessment data. When recommending a treatment protocol, "bottom-up and top-down treatment approaches are complementary and should both be incorporated to maximize treatment effectiveness" (p. 26).
"Speech-language pathologists are the professionals whose scope of practice includes assessment of the cognitive-communicative and language abilities associated with (C)APD. Speech-language pathologists frequently refer individuals to audiologists for central auditory testing on the basis of observed behavioral characteristics and/or results of a screening questionnaire or screening test. Speech-language pathologists can explore the possible impact of auditory processing-related deficits on specific aspects of language processing. Speech-language pathologists also are best prepared to provide a number of the interventions elaborated in the preceding section of these guidelines (e.g., central resources training)" (Class 5 Evidence; p. 30).
Central auditory processing disorders [(C)APD] must be diagnosed by an audiologist who is properly educated and trained in the area of (C)APD, including the administration and interpretation of tests and procedures. Other "professionals can and should be involved in the broad assessment of the functional deficits experienced by the individual with (C)APD and in planning the intervention activities needed to minimize those deficits" (p. 4).
<p>"Prior to administration of the central auditory test battery, the individual's peripheral auditory function should be evaluated with the goal of confidently ruling out or confirming middle ear and/or cochlear auditory dysfunction. A suggested test battery for assessment of peripheral auditory function includes:</p>
<ul>
<li>distortion product otoacoustic emissions (DPOAE) with multiple stimulus frequencies per octave from 500 to 8000 Hz and analysis with reference to normative data to detect objectively cochlear (outer hair cell) dysfunction;</li>
<li>immittance measures, including tympanometry and acoustic reflexes in uncrossed and crossed stimulus conditions;</li>
<li>pure-tone audiometry with air conduction stimuli at the conventional octaves, plus 3000 and 6000 Hz (bone conduction may not be necessary if findings are normal for DPOAEs and immittance measures; [and]</li>
<li>word recognition performance in quiet at a comfortable intensity level using recorded PB [phonetically balanced] word lists" (p. 19).</li>
</ul>
<p>A case history is recommended as an essential part of the diagnosis and management of individuals with central auditory processing disorders. The case history should obtain information about the: </p>
<ul>
<li>"auditory and/or communication difficulties experienced by the individual;</li>
<li>family history of hearing loss and/or central auditory processing deficits;</li>
<li>medical history, including birth, otologic and neurologic history;</li>
<li>general health history and medications;</li>
<li>speech and language development and behaviors;</li>
<li>educational history and/or work history;</li>
<li>existence of any known comorbid conditions, including cognitive, intellectual, and/or medical disorders;</li>
<li>social development and linguistic and cultural background;</li>
<li>prior and/or current therapy for any cognitive, linguistic, or sensory disorder or disability" (Class 4 & Evidence; p. 6-7).</li>
</ul>
When considering tests to assess central auditory processing disorders (C)APD, audiologists should consider test batteries with proven validity and efficiency for identification of central auditory nervous system dysfunction and for describing auditory behaviors in individuals affected by (C)APD. However, due to the lack of rigorous psychometric design, construction, and validation of tests for central auditory processing disorders, "clinicians are advised to peruse a test's manual and the published literature to fully evaluate a specific test's utility" (Class 2 & 3 Evidence; p. 15).
<p>Electrophysiological assessments may include:</p>
<ul>
<li>The auditory middle latency response (AMLR): the AMLR "appears to be underutilized at this time for evaluation of central auditory processing in children and adults.... Intra- rather than inter-subject comparisons provide better diagnostic information, based on data that reveals highly similar amplitudes from electrodes placed over each hemisphere in normal subjects" (Class 2 & 3 Evidence; p. 20).</li>
<li>Auditory late response (ALR): "Latencies beyond 50 ms elicited with non-speech and speech signals, which is comprised of the N1 and P2 evoked potentials and the P300 response.... N1 and P2 are sensitive to children with learning problems and related auditory processing problems" (Class 2 Evidence; p. 20).</li>
</ul>
Behavioral diagnostic testing for central auditory processing disorders should be undertaken with extreme caution for children ages 8 and under (Class 3, 4, & 5 Evidence; pp. 10, 14).
"Dichotic interaural intensity difference training and multimodal exercises (e.g., linking emotion of facial expression to prosody of a message, sound-symbol association) might be appropriate treatment procedures given findings of interhemispheric transfer deficits based on pattern test and dichotic test results and multidisciplinary assessment" (p. 26).
"There are no widely accepted criteria as to when [Auditory Evoked Responses] AERs should be included in the clinical evaluation of (C)APD ... although electrophysiologic results can provide objective information regarding acoustic signal transmission throughout the [central auditory nervous system] CANS, it should be remembered that neurophysiologic responses may be entirely normal in many cases of (C)APD because neurophysiologic deficits may be diffuse and not sufficiently localized to alter electrophysiologic recordings, such as in some cases of head injury.... In addition, even when neurophysiologic abnormalities are noted, these results provide little additional information (beyond that provided by the behavioral test results) regarding the functional difficulties experienced by the individual with (C)APD" (pp. 21-22).
<p>Clinicians considering alternative sound-based treatment programs (e.g., Beard Auditory Integration, Tomatis Approach, Listening Program) are advised to analyze the programs to:</p>
<ul>
<li>determine if they target the auditory deficit;</li>
<li>ensure the patient is an active, rather than passive, participant; and</li>
<li>determine if the treatment is consistent with the science and physiology of (C)APD (Class 4 & 5 Evidence; p. 27).</li>
</ul>
<p>The following behavioral tests are recommended as an important component of the central auditory test battery: </p>
<ul>
<li>Dichotic listening tests (Class 2, 3, & 4 Evidence).</li>
<li>Temporal sequencing tests such as the Frequency (or Pitch) Pattern Sequence Test, the Duration Patterns Test, and the Newcastle Auditory Test Battery (Class 2, 3, & 4 Evidence).</li>
<li>Monaural low-redundancy speech procedures (Class 3 & 4 Evidence).</li>
</ul>
<p>"Screening measures can be used to identify individuals who are 'at-risk' for [central auditory processing disorders] (C)APD and should be referred for diagnostic evaluation" (p. 13). The presence of one or more of the following behaviors characterize an individual as at-risk for central auditory processing disorders:</p>
<ul>
<li>"difficulty understanding speech in the presence of competing background noise or in reverberant acoustic environments;</li>
<li>problems with the ability to localize the source of a signal;</li>
<li>difficulty hearing on the phone;</li>
<li>inconsistent or inappropriate responses to requests for information;</li>
<li>difficulty following rapid speech;</li>
<li>frequent requests for repetition and/or rephrasing of information;</li>
<li>difficulty following directions;</li>
<li>difficulty or inability to detect the subtle changes in prosody that underlie humor and sarcasm;</li>
<li>difficulty learning a foreign language or novel speech materials, especially technical language;</li>
<li>difficulty maintaining attention;</li>
<li>a tendency to be easily distracted;</li>
<li>poor singing, musical ability, and/or appreciation of music; [and/or]</li>
<li>academic difficulties, including reading, spelling and/or learning problems" (Class 4 & 5 Evidence; p. 9).</li>
</ul>
"With appropriate speech stimuli, the Auditory Brainstem Response (ABR) appears to reflect processing of the temporal features of speech, in addition to documenting brainstem activation in response to stimulus onset. Speech-evoked ABR findings may also provide a prognostic indicator of benefit from (C)APD intervention" (Class 2 & 3 Evidence; p. 20).
"For young children suspected or 'at-risk' for (C)APD but for whom a definitive diagnosis has not yet been reached, enriched auditory stimulation and auditory 'games' (e.g., musical chairs, Simon Says) and/or software that exercises auditory sound recognition in noise, phoneme discrimination, etc. should be initiated and can involve families and educators" (p. 25).
