Data to calculate the incidence and prevalence of CAPD are not available due to the lack of universal, standardized diagnostic criteria. Guidance from national organizations varies. CAPD diagnosis varies widely depending on the criteria and the assessment instruments used. Some studies have estimated prevalence (the number of cases at a given point in time) as the following:

• Children:
  • 2%–3% (Chermak & Musiek, 1997; Palfery & Duff, 2007).
  • 7.3%–96% (Wilson & Arnott, 2013).
• Male to female ratio of 2:1 (Chermak & Musiek, 1997; Palfery & Duff, 2007).
• Adults 55 and older: 23%–76% (Cooper & Gages, 1991; Golding, Carter, Mitchell, & Hood, 2004; Stach, Spretnjak, & Jerger, 1990).

With the transition to the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM; American Medical Association, 2017), audiologists and physicians are able to assign a diagnostic code for CAPD in the medical record and for health insurance claims. Although coding does not address confounding factors of diagnostic criteria or assessment instrument variations, use of the new code will provide data on patients receiving care for CAPD.

Signs and symptoms of CAPD may include one or more of the following behavioral characteristics:

• Difficulty localizing sound
• Difficulty understanding spoken language in competing messages, in noisy backgrounds, in reverberant environments, or when presented rapidly
• Taking longer to respond in oral communication situations
• Frequent requests for repetitions, saying “what” and “huh” frequently
• Inconsistent or inappropriate responding
• Difficulty comprehending and following rapid speech
• Difficulty following complex auditory directions or commands
• Difficulty learning songs or nursery rhymes
• Misunderstanding messages, such as detecting prosody changes that help to interpret sarcasm or jokes
• Poor musical and singing skills
• Difficulty paying attention
• Being easily distracted
• Poor performance on speech and language or psychoeducational tests in the areas of auditory-related skills
• Associated reading, spelling, and learning problems
• Difficulty learning a new language

This list is illustrative, not exhaustive, and these behavioral characteristics are not exclusive to CAPD. They may be present with other disorders (e.g., learning disability, language impairment, ADHD, and autism spectrum disorder). The variability in specific auditory processing skill deficits may contribute to the variability in observed behaviors.

The etiology of CAPD may be linked to a specific lesion or disorder, or may be unknown. Causes and risk factors for CAPD may include the following (Bamiou, Musiek, & Luxon, 2001; Baran & Musiek, 1999; Chermak & Musiek, 2011):

• Age-related changes in CANS function
• Genetic determinants
• Neurological disorder, disease, or damage
  • Brain injury (e.g., head trauma, meningitis)
  • Cerebrovascular disorder (e.g., stroke)
  • Degenerative diseases (e.g., multiple sclerosis)
  • Exposure to neurotoxins (e.g., heavy metals, organic solvents)
  • Lesions of the central nervous system (CNS)
  • Seizure disorders
• Neuromaturational delay secondary to deafness/auditory deprivation
• Otologic disorder, disease, or injury (e.g., auditory deprivation secondary to recurrent otitis media)
• Prenatal/neonatal factors
  • Anoxia/hypoxia
  • Cytomegalovirus (CMV)
  • Hyperbilirubinemia
  • Low birth weight
  • Prematurity
  • Prenatal drug exposure

Roles and Responsibilities of Audiologists

Audiologists play a central role in the screening, assessment, diagnosis, and management of persons with CAPD as part of an interdisciplinary team. Professional roles and activities in audiology include clinical/educational services (diagnosis, assessment, planning, and management); prevention and advocacy; and education, administration, and research. See ASHA's Scope of Practice in Audiology (ASHA, 2018) and ASHA's Preferred Practice Patterns for the Profession of Audiology (ASHA, 2006).

Appropriate roles for audiologists involved in the assessment, diagnosis, and management of CAPD include the following:

• Remaining informed of research in the area of CAPD as related to the audiologist's contribution to patient management
• Educating other professionals about the needs of individuals with CAPD and the role of audiologists in CAPD management
• Participating in interdisciplinary team consultation (see ASHA's resource on Interprofessional Education/Interprofessional Practice [IPE/IPP]) for the assessment and management of CAPD
• Conducting comprehensive audiologic evaluations
• Obtaining a CAPD-specific case history
• Selecting an appropriate and individualized CAPD test battery
• Administering CAPD-specific assessments and interpreting the results
• Diagnosing CAPD
• Communicating results and recommendations to the patient/family and other appropriate parties
• Developing and implementing culturally and linguistically appropriate assessment and intervention plans as part of an interdisciplinary team
• Proceeding with assessment and fitting for hearing assistive technology systems (HATS), as appropriate
• Providing education and counsel to the patient and family
• Referring the patient to other professionals, as needed, to facilitate access to comprehensive services (e.g., speech-language pathology, psychology, neuro-otology, and neuropsychology)

As indicated in the Code of Ethics (ASHA, 2016a), audiologists who work in this capacity should be specifically educated and appropriately trained to do so.

Roles and Responsibilities of Speech-Language Pathologists

Speech-language pathologists (SLPs) play a role in the screening, assessment, and management of persons with CAPD as part of an interdisciplinary team. Professional roles and activities in speech-language pathology include clinical/educational services, prevention and advocacy, education, administration, and research. See ASHA's Scope of Practice in Speech-Language Pathology (ASHA, 2016b) and ASHA's Preferred Practice Patterns for the Profession of Speech-Language Pathology (ASHA, 2004).

Appropriate roles and responsibilities for SLPs involved in the assessment and management of CAPD and language processing disorders include the following:

• Remaining informed of research in the area of CAPD as related to the SLP's contribution to patient management
• Educating other professionals about the needs of individuals with CAPD and the role of SLPs in CAPD management
• Participating in interdisciplinary team consultation (see ASHA's resource on Interprofessional Education/Interprofessional Practice [IPE/IPP]) for the assessment and management of CAPD
• Collecting information about skills related to auditory processing (e.g., auditory working memory, auditory comprehension) using a variety of screening and assessment instruments
• Conducting comprehensive cognitive-communication and speech and language assessments.
• Obtaining a CAPD-specific case history
• Identifying the cognitive-communicative and/or speech and language factors that may be associated with CAPD
• Providing a clinical description of the patient's speech perception
• Helping to identify or differentiate disorders in phonology or language processing that may be comorbid to CAPD
• Helping to determine the precise nature of the diagnosed disorder(s) and the functional implications associated with the disorder(s)
• Communicating results and recommendations to the patient/family and other appropriate parties
• Developing and implementing culturally and linguistically appropriate assessment and intervention plans as part of an interdisciplinary team
• Providing education and counsel to the patient and family
• Referring the patient to other professionals, as needed, to facilitate access to comprehensive services (e.g., audiology, psychology, and neuropsychology)

As indicated in the Code of Ethics (ASHA, 2016a), SLPs who work in this capacity should be specifically educated and appropriately trained to do so.

Team Approach

Diverse perspectives among interdisciplinary team members involved in the evaluation process may result in different diagnoses (e.g., CAPD, phonological awareness disorder, language processing disorder; McNamara, Bailey, & Harbers, 2008; Richard, 2012). Therefore, a team including both audiologists and SLPs is valuable in the diagnosis of CAPD and the identification of language disorders that occur in association with CAPD.

• Audiologists are responsible for evaluating and diagnosing problems in the reception and/or transference of auditory signals in the peripheral auditory system and the CANS.
• SLPs are responsible for evaluating and diagnosing problems in the linguistic processing of the auditory signal.
• Audiologists and SLPs share responsibility for diagnosing problems in the phonemic processing of the auditory signal (Richard, 2013).

Screening

The goal of screening for a CAPD is to identify individuals who are potential candidates for a more comprehensive central auditory testing battery. Screening can be accomplished using abbreviated test protocols. A number of questionnaires and checklists are available to probe auditory behaviors related to academic achievement, listening skills, and communication and to allow for systematic observation of listening behavior.

There is no universally accepted method for screening for CAPD. There remains a need for valid and efficient screening tools.

Comprehensive Assessment

There is currently no reference standard for diagnosing CAPD (American Academy of Audiology [AAA], 2010; ASHA, 2005; Vermiglio, 2016). The audiologist, on the basis of clinical presentation and the findings of assessment measures, makes the diagnosis of CAPD. There may be difficulties associated with diagnosing CAPD due to its heterogeneous presentation and the frequent overlap in symptoms with language disorders.

Assessment data may be gathered by the audiologist, the SLP, and other members of the interdisciplinary team (e.g., psychologist, special educator). These assessment data may identify the presence of disorders with symptoms similar to CAPD (e.g., peripheral hearing loss, ADHD, speech-language disorder, cognitive deficits) and help determine if further CAPD testing is warranted. The order in which assessments are completed may vary depending on the referral source and the needs of the individual (e.g., symptoms, case history information).

Case History

Case history information is obtained by one or more professionals involved in the comprehensive assessment process and may include the following:

• Age, including chronological and mental age in early childhood and age-related decline in older adults
• Auditory/behavioral complaints (e.g., difficulty understanding speech in noisy or reverberant environments, difficulty localizing sound, difficulty hearing on the phone, difficulty following rapid speech, difficulty following directions, inability to detect humor or sarcasm [prosody], distractibility, inattention)
• Cognitive status and psychological factors (e.g., attention, memory, motivation)
• Cultural and linguistic background (e.g., native language)
• Educational achievement (e.g., academic, learning, reading difficulties)
• Family/genetic history
• Health status (e.g., medical history and medications, previous illness or injury)
• Hearing status (e.g., peripheral auditory system)
• Pre-, peri-, and postnatal course (e.g., congenital and early infancy events)
• Prior and current related therapies
• Risk factors and comorbidities (e.g., learning disabilities, traumatic brain injury [TBI], epilepsy)
• Social development
• Speech, language, and literacy concerns

Audiologic Assessment Components

Audiologic Evaluation of Peripheral Auditory System

An undiagnosed hearing loss may contribute to behavioral complaints. The presence of a peripheral hearing loss does not necessarily preclude the assessment of CAPD; however, it may differentially affect testing (Baran & Musiek, 1999). When evaluating an individual with hearing loss, tests that use stimuli minimally affected by peripheral impairment should be used whenever possible (Musiek, Baran, & Pinheiro, 1990). In some cases (e.g., profound hearing loss), testing cannot be completed.

Peripheral auditory disorders include conductive, sensorineural, and mixed hearing loss, as well as auditory neuropathy (Norris & Velenovsky, 2014) and cochlear synaptopathy (i.e., hidden hearing loss; Liberman, Epstein, Cleveland, Wang, & Maison, 2016). These disorders can affect an individual's ability to hear and understand speech in background noise to varying degrees. See the assessment sections of ASHA's Practice Portal pages on Hearing Loss in Adults and Hearing Loss in Children for information on assessing the peripheral auditory system.

Audiologic Evaluation of Central Auditory System

The audiologist selects the appropriate CAP test battery, on the basis of findings from the case history, interdisciplinary assessment (e.g., results of language and cognitive assessments), and peripheral audiologic evaluation. Audiologists should have knowledge of the strengths and weaknesses of the individual tests, required response mode, and areas of the CANS to which each test is most sensitive (Chermak, Bamiou, Iliadou, & Musiek, 2017).

The test battery may be used to diagnose impairment in one or more neurophysiologic processes that occur as auditory signals travel through the CANS. The identification of specific deficits in the CANS can lead to targeted recommendations and treatment plans.

There are two types of audiologic evaluation measures that can be used to assess auditory processing skills.

• Behavioral—assesses the functional capabilities of the auditory system
  • Auditory discrimination tests to assess the ability to differentiate similar acoustic stimuli that differ in frequency, intensity, and/or temporal parameters.
  • Auditory temporal processing and patterning tests to assess the ability to analyze acoustic events over time.
  • Dichotic speech tests to assess the ability to separate (i.e., binaural separation) or integrate (i.e., binaural integration) disparate auditory stimuli presented to each ear simultaneously.
  • Monaural low-redundancy speech tests to assess the recognition of degraded speech stimuli presented to one ear at a time, including speech-in-noise, speech-in-competition, low-pass filtered speech, or compressed (rapid) speech.
  • Binaural interaction tests to assess the ability to combine complementary inputs distributed between the ears, synthesizing intensity, time, or spectral differences of otherwise identical stimuli presented simultaneously or sequentially.

  For a discussion of behavioral tests, see McNamara and Hurley (2017).

• Electrophysiologic—assesses neural processes in the central auditory pathway and provides information about the integrity of the CANS from the vestibulocochlear nerve (also known as the "auditory vestibular nerve" or "eighth cranial nerve") to the auditory cortex. These measures include auditory brainstem response (ABR), middle latency response (MLR), late cortical response, P300, and mismatch negativity.

  Electrophysiologic measures may be useful in cases where behavioral procedures are not feasible (e.g., infants and very young children, non-English speakers), when there is suspicion of frank neurologic disorder, when a confirmation of behavioral findings is needed, or when behavioral findings are inconclusive.

Test Principles of an Audiologic Evaluation of the Central Auditory System

Principles applied when determining the composition of a central auditory test battery include the following:

• The test battery process should not be test-driven; rather, it should be motivated by the referring complaint(s) and the relevant information available to the audiologist.
• A central auditory test battery should include measures that are sensitive to the integrity of the CANS.
• Tests should examine different central processes, tasks, and the integrity of multiple levels and regions of the CANS.
• Most available behavioral central auditory tests are more appropriate for administration to children 7 years of age and older due to the challenging nature of the tasks and considerable performance variability.
• Communication checklists, language tests, and cognitive tests can be used to identify younger children that may be "at risk" for auditory difficulties (Moore et al., 2013). A diagnosis should be withheld until formal testing can be completed.
• Tests should generally include both nonverbal and verbal stimuli to examine different aspects of auditory processing and different levels of the auditory nervous system.
• Individuals who are medicated successfully for attention, anxiety, or other disorders that may confound test performance should be tested under the influence of their medication.
• Neuromaturation, subject state, and cognitive factors may affect the outcomes of many electrophysiologic procedures when used with children younger than 10 years of age. These measures need to be administered and interpreted accordingly.
• The duration of the test session should be appropriate to the individual's attention, motivation, and energy level. As with all behavioral tests, it is important to monitor the individual's level of attention and effort and to take steps to maintain motivation throughout testing.
• Referral to the appropriate professional(s) should be made when there is a suspected speech or language impairment or intellectual, psychological, or other deficit. In some cases, this referral should precede CAP testing to ensure accurate interpretation of test results. Comorbid diagnoses may preclude CAP testing (e.g., significant intellectual deficit, severe hearing loss).
• Test findings should be corroborated by relating them to the individual's primary symptoms or complaints (e.g., difficulty hearing with the left ear vs. the right ear, difficulty understanding rapid speakers, difficulty hearing in the presence of competing noise).

Interpretation of Central Auditory Diagnostic Test Battery

Norm-based interpretation of test results involves comparing the individual's performance to normative group data. Patient-based interpretation involves comparing the individual's performance to their own baseline performance. Comparison of results observed across disciplines can also be helpful with interpretation.

Examples of suggested diagnostic criteria and interpretations of test results include the following:

• Performance deficits are noted in one or both ears of at least two standard deviations below the mean on two or more tests in the battery (Chermak & Musiek, 1997).
• If poor performance is observed on only one test:
  • Diagnosis may be withheld unless performance falls at least three standard deviations below the mean or the finding is accompanied by significant functional difficulty in auditory behaviors that rely on the process being assessed.
  • The failed test—and other tests that assess the same process—should be re-administered to confirm initial findings.
• Administering and comparing results for several tests that measure the same auditory process can be used to look for patterns in auditory processing abilities and to support the findings of the evaluation.
• Inconsistencies across tests might signal the presence of a non-auditory confound, even when CAPD criterion is met. Likewise, pervasive deficits on all tests may signal a cognitive deficit or other non-auditory confound.

Interdisciplinary Contributions to Assessment

Various professionals may be involved in providing essential information during the assessment period.

Speech and Language Assessment

A comprehensive speech and language assessment includes assessment of spoken and written language; phonemic awareness (e.g., ability to segment and blend sounds in syllables and words); phonological working memory and phonological retrieval; and social communication. See ASHA's Practice Portal pages on Spoken Language Disorders, Written Language Disorders, Speech Sound Disorders: Articulation and Phonology, and Social Communication Disorders.

Psychoeducational or Cognitive Assessment

These assessments include tests of memory, executive functioning, and attention. An educational psychologist or cognitive psychologist may perform these assessments.

Differential Diagnosis

CAPD is an auditory deficit; therefore, the audiologist is the professional who makes the diagnosis (ASHA, 2005). "However, many disorders present behavioral characteristics similar to CAPD that can cause the listener to perform poorly on behavioral central auditory function tests and/or exhibit similar functional listening difficulties" (Ferre, 2014, p. 589). Interdisciplinary assessment and differential diagnosis of CAPD and related/comorbid disorders is important in the development of appropriate intervention strategies. See also De Wit et al. (2017).

SLPs diagnose cognitive-communication and language-related disorders (including language processing disorders) that may co-occur with CAPD. Differentiating between language and phonological processing disorders and CAPD requires collaboration between audiologists and SLPs.

CAPD may affect listening, communication, academic success, and psychosocial wellness. The overall goal of intervention is to provide the individual with the ability to communicate more effectively in everyday contexts (e.g., home, classroom, work, community). Efforts to improve acoustic access and communication for individuals of any age requires an analysis of functional deficits and specific recommendations for change across settings.

A team approach to treatment is often utilized. Depending on the needs of the individual, team members may include an audiologist, an SLP, a teacher, parents, and a counselor. The approach, frequency, and intensity of treatment should be individualized based on communication strengths and needs, cultural background and values, preferred language, severity of the disorder, and available research evidence. See ASHA'S Practice Portal pages on Bilingual Service Delivery and Cultural Responsiveness.

Treatment goals are based on

• needs identified during the assessment process;
• the individual's case history;
• related speech-language and psychoeducational assessment data;
• remediation of deficit skills; and
• management of the disorder's impact on the individual.

Treatment approaches should

• be based on the best available evidence;
• follow learning principles;
• strive to reduce functional deficits;
• strive to maximize generalization; and
• occur in multiple settings as appropriate—home, classroom, workplace, and community.

Three treatment approaches for individuals diagnosed with CAPD, often used concurrently, include the following (ASHA, 2005):

1. Direct skills remediation (auditory training, "bottom-up")
2. Compensatory strategies (recruiting higher-order skills to help compensate for the disorder "top-down")
3. Environmental modifications (changing the learning or communication environment).

It is essential to consider the comorbidity of CAPD with other spoken and written language disorders (Sharma, Purdy, & Kelly, 2009) and the heterogeneity of CAPD when providing treatment (Fey et al., 2011; Richard, 2012). The focus of treatment is guided by the findings of a comprehensive assessment. Some treatment approaches and tasks may be the same as those used for spoken or written language disorders (Kamhi, 2011; Richard, 2013), given the overlap in functional symptoms of CAPD and language disorders. See the treatment sections of ASHA's Practice Portal pages on Spoken Language Disorders and Written Language Disorders.

This list of treatment approaches is not exhaustive, and the inclusion of any specific treatment does not imply endorsement by ASHA.

Direct Skills Remediation

Direct skills remediation (e.g., auditory training; sometimes referred to as "bottom-up" or "traditional listening treatments") includes procedures to target multiple skills associated with auditory processing (Bellis, 2002, 2003; Chermak & Musiek, 2002; cf. British Society of Audiology [BSA], 2011).

Direct skills remediation may address the following:

• Auditory discrimination—training to distinguish the intensity, frequency, and duration of one sound from another
• Phoneme discrimination—training to distinguish between speech sounds that make a difference in meaning in a particular language (e.g., /p/ vs. /b/ in English) and phoneme–grapheme skills (written representation of phonemes)
• Temporal aspects of audition—training to perceive acoustic signals over time, including
  • temporal integration;
  • temporal gap discrimination; and
  • temporal ordering or sequencing.
• Auditory pattern recognition—training to distinguish similarities and differences in sound patterns
• Sound localization and lateralization—training to identify the location, origin, direction, and distance of a sound reaching each ear
• Recognition of auditory information presented within a background of noise or competition (i.e., binaural separation)—dichotic listening training or speech-in-noise training
• Recognition of disparate auditory stimuli presented to each ear simultaneously (i.e., binaural integration)—binaural interaction training (Bamiou, Campbell, & Sirimanna, 2006; Bellis, 2003; Bellis & Anzalone, 2008)

Computer-Based Training

Direct skills remediation includes computer-based training programs that may address both auditory and language components. Consequently, it may be difficult to isolate the specific factors contributing to treatment outcomes (Gillam et al., 2008; Richard, 2012). Some programs "are designed to capitalize on the plasticity of the [auditory] system" (Tremblay & Kraus, 2002). As with all other treatments, it is important that computer-based training be individualized and carefully monitored by an audiologist or SLP. More research is needed in the area of direct skills computer-based treatment approaches (Musiek, Shinn, & Hare, 2002; Phillips, 2002).

Available programs focus on

• temporal processing;
• linguistic and nonlinguistic auditory memory;
• linguistic and non-linguistic dichotic ability,
• speech-in-noise;
• binaural integration and separation skills;
• phonological awareness; and
• reading decoding and comprehension.

Computerized delivery may provide

• multisensory stimulation;
• engaging formats;
• feedback and reinforcement; and
• facilitation of intensive training.

Interhemispheric Transfer Training

Direct skills remediation also includes exercises to train interhemispheric transfer (Bellis, 2002, 2003; Musiek, Baran, & Schochat, 1999). Interhemispheric transfer of information underlies binaural hearing and binaural processing. Efficacy data in this area are still emerging (Weihing, Chermak, & Musiek, 2015).

Exercises to train interhemispheric transfer include

• tasks that address interaural temporal offsets and intensity differences;
• unimodal tasks (e.g., linking prosodic and linguistic acoustic features); and
• multimodal tasks (e.g., writing to dictation, verbally describing a picture while drawing).

Compensatory Strategies

Compensatory strategies (e.g., metalinguistic and metacognitive; sometimes referred to as "top-down") are designed to minimize the impact of CAPD on language, cognition, and academics. They focus on strengthening higher-order central resources (e.g., language, memory, and attention) to enhance listening skills, communication, social skills, and learning outcomes.

• Metalinguistic strategies include
  • schema induction (i.e., predicting elements in a message) and discourse cohesion devices (i.e., grammatical means to link and establish relationships between sentences and paragraphs);
  • use of graphic organizers (e.g., problem–solution map; story map; semantic network tree);
  • use of context to understand and build vocabulary;
  • phonological awareness (see BSA, 2011, Appendix K);
  • semantic network expansion; and
  • active listening (see BSA, 2011, Appendix N).
• Metacognitive strategies include
  • self-instruction;
  • organization skills;
  • metamemory techniques (e.g., mnemonics, mind mapping);
  • problem solving; and
  • assertiveness training.

Language/Curricular-Based Treatment Approaches

Some students may benefit from carefully targeted individualized language interventions.

This applied curricular approach falls within the area of "top-down" or compensatory strategies. It "places CAPD symptoms within a broader framework and takes into account the complex interaction among the language knowledge, skills, and strategies needed for academic success" (Wallach, 2011, p. 273).

This broader-based information and linguistic processing framework (Cowan, Rosen, & Moore, 2008; Gillam, Hoffman, Marler, & Wynn-Dancy, 2002; Kamhi, 2004; Nittrouer, 1999, 2002) focuses on the linguistic aspects of auditory processing deficits and includes linguistic goals.

Considerations for a strategic-based language/curriculum-relevant approach (based on Wallach, 2011) include the following:

• Focus on enhancing language comprehension and production skills to help students with auditory weaknesses access curricular content (Kaderavek, 2011). For example, help students learn concepts and skills such as paraphrasing, explaining differences, knowing word meanings, and using complex syntax.
• Address language knowledge, skills, and strategies that underlie academic tasks (Ehren, 2000; Ehren, Lenz, & Deshler, 2006).
• Select goals for contextualized (e.g., language accompanied by gesture, facial, and other supports) and decontextualized (e.g., language within testing contexts, many written materials) aspects of language (Wallach, 2008).
• Recognize that metalinguistic aspects are involved in auditory tasks (e.g., sentence memory tasks involve metalinguistic knowledge of sentence structure; auditory discrimination tasks involve phonemic judgments and the metalinguistic ability to analyze the sound structure of language (Schuele & Boudreau, 2008; van Kleeck, 1994).
• Identify curricular and instructional demands across grades, and determine the impact on language use. Recognize the need for disciplinary literacy—each academic subject has its own language (Ehren et al., 2006; Heller & Greenleaf, 2007; VanSledright, 2002, 2004).
• Develop language interventions that focus on content-area subjects. Connect with school-based colleagues, and consider curriculum demands placed on students (Brozo, 2010; Wallach, Charlton, & Christie, 2009).
• Teach strategies to help students derive meaning from spoken and written language and organize incoming information (Blachowicz & Fisher, 2004; Ehren, 2009; McKeown, Beck, & Blake, 2009; Nippold, 2009). For example, create expectancies for what they are likely to hear in the classroom; expectancies will influence what is attended to, perceived, and remembered.
• Understand the reciprocal nature of spoken and written language. Written language skills can facilitate auditory processing by improving metalinguistic awareness and by introducing various language forms and new vocabulary (Schuele & Boudreau, 2008; Scott, 2009; van Kleeck, 2006; Zucker, Justice, & Piasta, 2009).

Environmental Modifications

Environmental modifications improve access to auditorily presented information (ASHA, 2005). They include enhancement of the auditory signal and the listening environment ("bottom-up") to improve clarity and/or audibility of the signal itself (Crandell & Smaldino, 2000, 2001) and management approaches ("top-down") to improve access to information in various settings (Bellis, 2002, 2003; Chermak & Musiek, 1997; Hedu, Gagnon-Tuchon, & Bilideau, 1990).

Enhancement of the Auditory Signal and Listening Environment (Bottom-Up)

• Enhancement of the auditory signal—using remote microphone hearing assistive technology, including individual and group assistive listening devices such as FM/DM or infrared technology—
  • may be indicated for some individuals with CAPD when deficits are found on monaural low redundancy speech and dichotic speech tests (Bellis, 2003; Rosenberg, 2002), both of which involve degraded signals, figure ground, or competing speech—factors similar to the effects of noise and reverberation in various settings; and
  • may be considered initially for individuals with CAPD as an accommodation strategy due to their signal-to-noise (S/N) enhancement capabilities (Crandell, Charlton, Kinder, & Kreisman, 2001).
  • Prior to fitting, performance should be verified using electroacoustic, real-ear, and behavioral measures, including norm-referenced speech recognition in noise testing (AAA, 2008).
  • Subsequent to fitting, benefits should be validated in typical listening conditions experienced by the individual using a variety of outcomes tools (AAA, 2008).

  More research is needed regarding the use of personal HATS as a management strategy for CAPD (Lemos et al., 2009; Rosenberg et al., 1999; Stach, Loiselle, Jerger, Mintz, & Taylor, 1987).

• Modifications to the listening environment—improving acoustics that can affect speech intelligibility—can include
  • covering reflective surfaces (e.g., black/white boards not in use, linoleum or wood floors, untreated ceilings) to decrease reverberation;
  • using properly placed acoustic dividers;
  • using various absorption materials throughout open or empty spaces; and
  • reducing competing signals by eliminating or moving external noise sources (e.g., aquariums, fluorescent lights that hum) from the learning space.

See ASHA's technical report on school facilities (2002), ASHA's Practice Portal page on Classroom Acoustics, and The Stationery Office's bulletin on the acoustic design of schools (The Stationery Office Department for Education and Skills, 2003).

Management Approaches (Top-Down)

• Top-down management approaches—compensatory strategies designed to strengthen higher order resources (i.e., language, memory, attention) and buttress deficient auditory processing skills and enhance listening, including
  • advising the speaker to speak more slowly, pause more often, emphasize key words, and "chunk" their instructions;
  • asking the speaker to check that the listener has understood and knows to use repetition and rephrasing when communication breakdowns occur;
  • pairing verbal presentations or instructions with visuals;
  • using written supports such as e-mail or mind maps; and
  • providing support for focused/attentive listening (e.g., use notetakers, preview information prior to instruction, and use organizers).

Assessing Treatment Progress

Test–retest of standardized measures as well as academic/learning measures may be used to assess treatment progress. Measures may include indices of auditory performance (e.g., pattern tests, dichotic digits, speech recognition for time-compressed speech), functional indices of metalanguage (e.g., phonemic analysis, phonemic synthesis), and/or global measures of listening and communication (e.g., self-assessment or informant communication and education scales).

As listening and learning demands change over time, alterations to the treatment and management plan will be indicated. It is important that the relative efficacy of each treatment and management approach implemented be monitored on an ongoing basis and that changes be made as needed.

Special Considerations: Adolescents and Adults

Children with processing deficits may have more difficulty as they enter noisy auditory-based learning environments with high demands on their listening skills. As educational and vocational communication demands change or increase, adolescents and adults may experience more difficulties with understanding and listening. In addition, an acquired deficit, such as TBI or a stroke, may lead to spoken language disorders, which may have an auditory component.

The following considerations may be applicable for adolescents and adults with a CAPD diagnosis:

• Make adjustments based on different contextual demands at home, school, work, and in the community (e.g., focusing in an open cubicle at work; processing information in challenging listening environments, such as large classrooms or lecture halls)
• Provide multiple treatment options, such as academic and vocational training, career counseling, and transition planning
• Assist with self-advocacy

Service Delivery

In addition to determining the type of treatment that is optimal for individuals diagnosed with CAPD, audiologists and SLPs should consider other service delivery variables that may have an impact on treatment outcomes.

Dosage

Dosage refers to the frequency, intensity, and duration of service and the culmination of those three variables (Warren, Fey, & Yoder, 2007).

Format

Format refers to the structure of the treatment session (e.g., individual or part of a group). The appropriateness of treatment format (individual vs. group vs. both) depends on the primary goal for the individual at a particular point in the treatment process.

Provider

Provider refers to the person providing the treatment (e.g., audiologist, SLP, trained volunteer, caregiver). It is important for audiologists and SLPs to collaborate with each other and with other professionals regarding treatment alternatives, including opportunities for co-treatment.

Timing

Timing refers to timing of intervention relative to diagnosis. When an individual is diagnosed with CAPD, they may present with speech, language, and communication disorders that warrant immediate intervention.

Setting

Setting refers to the location of treatment (e.g., home, school, work, community-based,). A naturalistic treatment environment is important for facilitating generalization and carryover of skills, and home practice is essential for helping an individual make optimal progress.

Regulations

A recent court decision by the United States Ninth Circuit Court of Appeals (2012) determined that an auditory processing disorder constitutes an "other health impairment" under the Individuals with Disabilities Education Improvement Act (IDEA, 2004). See E. M. . . . v. Pajaro Valley Unified School District [PDF]. This court case helped define CAPD under the IDEA for school administrators and educators, parents, the judiciary, and administrative bodies and legal representatives in the western states.

Court filings related to the case described CAPD (also referred to as "auditory processing disorder") as a deficiency in neurological processing that adversely affects an individual's ability to identify and distinguish similar sounds and understand oral communication. In addition, evidence introduced in court established that CAPD requires a diagnosis by an audiologist.

In addition to helping define CAPD, this court case could also improve access to services under IDEA in public school settings. Court documents revealed that, given the similarity of symptoms caused by CAPD and ADHD, CAPD clearly falls within the scope of identified illnesses that could be covered by "other health impairment." CAPD can satisfy the three elements of an "Other Health Impairment:" (1) a chronic medical condition (2) that impacts a child's alertness in a classroom and 3) adversely affects the child's ability to learn.

Some state education departments may review eligibility for CAPD under the IDEA disability categories of "Speech or Language Impairment" or "Specific Learning Disability." However, establishing CAPD in the category of "Other Health Impairment" provides a specific and recognized category with which to argue for service eligibility.

Reimbursement

CAPD Coding

The International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) is a set of diagnostic codes used by physicians, hospitals, and health care professionals, including audiologists and SLPs, to indicate diagnoses for all patient encounters.

In October 2015, the ICD-10-CM diagnostic category for CAPD changed (World Health Organization, 2015). Previously, the International Classification of Diseases, Ninth Revision (ICD-9) described CAPD as part of "Developmental Speech-Language Deficits"—specifically, "Mixed Receptive-Expressive Language Disorder; Central Auditory Processing Disorder." In the new code, CAPD is no longer described as a developmental speech-language disorder. It is listed in the chapter, "Diseases of the Ear and Mastoid Process," indicating the medical nature of the deficit. This could help with coverage by public and private payers because developmental conditions are often denied coverage. As a medical condition, CAPD may better meet medical necessity criteria.

Billing for Services

Providing appropriate procedure codes for evaluation and treatment is an important aspect of successfully billing for services. Payer policies often outline specific coverage guidelines and list relevant ICD-10-CM and Current Procedural Terminology (CPT) codes (American Medical Association, 2017).

Diagnostic and procedure codes that audiologists and SLPs use to describe CAPD-related evaluation and treatment include CPT codes and ICD-10-CM diagnostic codes. Coding options are different for each discipline. For more information about coding, see the following ASHA resources:

• Coding for Reimbursement Frequently Asked Questions: Audiology—What code/s should I use for auditory processing (AP) evaluation and treatment?
• Coding for Reimbursement Frequently Asked Questions: Speech-Language Pathology—What code/s should I use for auditory processing (AP) evaluation and treatment?

Payer policies regarding coverage of CAPD vary. SLPs working with private insurance should verify coverage based on each individual.

Medicaid may provide for CAPD services. For example, in North Carolina, services are covered—but only in the school setting. See Medicaid and Health Choice Clinical Coverage Policy No. 10C [PDF] (North Carolina Division of Medical Assistance, 2015).

ASHA Resources

• ASHA Blog: Does Auditory Processing Disorder Meet the Criteria for a Legitimate Clinical Entity?
• ASHA Blog: Dig Deeper If Treating a Child With Suspected APD
• ASHA Leader: Don't Wait to Diagnose Auditory Processing Disorder
• Central Auditory Processing and the Common Core
• (Central) Auditory Processing Disorders—The Role of the Audiologist
• Coding for Reimbursement Frequently Asked Questions: Audiology—What code/s should I use for auditory processing (AP) evaluation and treatment?
• Coding for Reimbursement Frequently Asked Questions: Speech-Language Pathology—What code/s should I use for auditory processing (AP) evaluation and treatment?
• Interprofessional Education/Interprofessional Practice (IPE/IPP)
• Understanding Auditory Processing Disorders in Children
• Tips for the Differential Diagnosis of Central Auditory Processing Disorder (CAPD) - [ASHA Case Study Video; Ferre, 2016]
• Understanding the Differences Between Auditory Processing, Speech and Language Disorders, and Reading Disorders [PDF]

Other Resources

This list of resources is not exhaustive and the inclusion of any specific resource does not imply endorsement from ASHA.

• American Academy of Audiology Clinical Practice Guidelines—Diagnosis, Treatment and Management of Children and Adults With Central Auditory Processing Disorder [PDF]
• Audiology Australia Professional Practice Standards—Part B Clinical Standards [PDF]
• Auditory Processing Disorder Foundation
• British Society of Audiology—Practice Guidance: An Overview of Current Management of Auditory Processing Disorder [PDF]
• Canadian Guidelines on Auditory Processing Disorder in Children and Adults: Assessment and Intervention [PDF]
• E.M. . . . v. Pajaro Valley Unified School District [PDF]—Court Decision Establishes CAPD as an Other Health Impairment Under IDEA
• National Acoustic Laboratories (NAL)—Position Statement on Auditory Processing Disorders
• North Carolina Medicaid and Health Choice Clinical Coverage Policy No. 10C [PDF]
• Understood—Understanding Auditory Processing Disorder

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Acknowledgements

Content for ASHA's Practice Portal is developed through a comprehensive process that includes multiple rounds of subject matter expert review. ASHA extends its gratitude to the following subject matter experts who reviewed content and provided feedback during the development of this page.

• Jane A. Baran, PhD, CCC-A/SLP
• Gail D. Chermak, PhD, CCC-A
• Ellen de Wit, MSc 
• Tatyana Elleseff, MA, CCC-SLP
• Jeanane M. Ferre, PhD, CCC-A
• Alan G. Kamhi, PhD, CCC-SLP
• Georgina T. Lynch, PhD, CCC-SLP
• Tena L. McNamara, AuD, CCC-A/SLP
• Cynthia McCormick Richburg, PhD, CCC-A
• Deborah Ross-Swain, EdD, MS, CCC-SLP
• Andrew J. Vermiglio, AuD, CCC-A
• Geraldine P. Wallach, PhD, CCC-SLP

In addition, ASHA thanks the members of the American Speech-Language-Hearing Association (ASHA) Working Group on Auditory Processing Disorders whose work was foundational to the development of this content. Members of the working group (2002–2004) were Teri James Bellis (chair), Gail D. Chermak, Jeanane M. Ferre, Frank E. Musiek, Gail G. Rosenberg, and Evelyn J. Williams (ex officio). Members of the Working Group (2002–2003) included Jillian A. Armour, Jodell Newman Ryan, and Michael K. Wynne. Susan J Brannen, member 2004 and vice president for professional practices in audiology (2001–2003) and Roberta B. Aungst, vice president for professional practices in audiology (2004–2006) served as monitoring vice presidents.

Citing Practice Portal Pages

The recommended citation for this Practice Portal page is:

American Speech-Language-Hearing Association. (n.d.). Central Auditory Processing Disorder. (Practice Portal). Retrieved month, day, year, from www.asha.org/Practice-Portal/Clinical-Topics/Central-Auditory-Processing-Disorder/.