Lecture 13 Central Auditory Processing Disorder

Nomenclature

• Name of disorder is not universal.

• Professional organization commonly refer to disorder as:

  • Central Auditory Processing Disorder (CAPD)

  • Auditory Processing Disorder (APD)

  • Auditory Processing (AP)

CAPD as defined by ASHA (2005)

“central auditory processing (CAPD) refers to the efficiency and effectiveness by which the central nervous system (CNS) utilizes auditory information....(CAPD) refers to the difficulties in the perceptual processing of auditory information in the central nervous system and the neurobiological activity that underlies that processing and give rise to the electrophysiologic auditory potentials...CAPD may co-exist with other disorders (e.g., attention- deficit/hyperactivity disorder (ADHD), language impairment, and learning)...”

CAPD simply defined

• Deficit with the neural processing of auditory information in the central auditory nervous system (CANS) which is not caused by peripheral hearing loss, higher-order language deficits, or cognitive deficits.

• "Auditory processing is what the brain does with what the ears hear." - Jack Katz, Ph.D., CCC-A/SLP

Prevalence of CAPD

• Difficult to answer due differences between test batteries and criteria.

• Studies have shown very different results in the prevalence of CAPD

  • Likely due to no “gold standard” test battery

    • Disagreement in criteria

• There is a tremendous need for further CAPD research

• CAPD affects both children and adults

Symptoms of CAPD Examples (ASHA)

• difficulty localizing sound

• difficulty understanding spoken language in competing messages, in noisy backgrounds, in reverberant environments, or when presented rapidly

• longer response time during oral communication

• frequent requests for repetitions

• inconsistent or inappropriate responses during oral communication

• difficulty comprehending rapid speech

• difficulty following complex auditory directions

• difficulty learning songs or nursery rhymes

• misunderstanding messages (e.g., difficulty detecting prosody changes that help to interpret sarcasm or jokes)

• poor musical and singing skills

• difficulty paying attention or avoiding distractions

• reading, spelling, and/or learning problems

Symptoms of CAPD (ASHA)

• No one behavior exclusively represents CAPD

• Differential diagnosis can be difficult

  • CAPD vs

    • ASD?

    • AD/HD?

    • Language deficit?

Possible Scenario (Case History)

• Patient presents with significant concerns and complaints about their ability to understand friends and family.

• Family reports patient seems hard of hearing or does not pay attention.

• Patient reports difficulty localizing the source of sounds.

Possible Scenario (Test Results)

• Normal otoscopy and tympanogram

• Normal otoacoustic emissions

• Normal pure tone thresholds

• Normal SRT and WRS

Who can be tested for CAPD?

• Traditionally, testing was not administered until a child was at least seven years old

• Concerns with increased inconsistently and weaker reliability

• Limited availability of normative data

• Some tests have started to be completed by children younger than seven

• AAA (2010) discusses using a limited test battery with tests designed for young children to identify those “at-risk”.

• Those children identified would be monitored closely, provided with enrichment activities, and tested for a definitive diagnosis as early as possible

• Even if a child is too young for CAPD testing, they should be referred for hearing evaluation

Role of SLPs

Are part of an interdisciplinary team playing a role in the identification, screening, assessment, and treatment.

• Educate other professionals about the needs of individuals with CAPD and the role of SLPs in CAPD treatment.

• Screen auditory processing skills in individuals identified as at risk for CAPD and determine if a referral for a diagnostic CAPD evaluation is warranted.

• Conduct a comprehensive and culturally and linguistically responsive evaluation of speech, language, cognitive, social, and communication skills.

• Identify or differentiate disorders in phonology or language processing that may co-occur with CAPD.

• Provide education and counseling to the patient and their family

Role of Audiologists

Play a primary role in the identification, screening, assessment, diagnosis, and treatment of individuals with central auditory processing disorder (CAPD).

• Conduct a comprehensive, culturally and linguistically responsive, audiologic evaluation.

• Select an individualized and person-centered CAPD test battery.

• Administer CAPD-specific assessments and interpret the results.

• Diagnose CAPD.

• Communicate results and recommendations to the patient, their family, and other relevant parties (e.g., interprofessional team members) in a health-literate and person- and family-centered manner.

• Develop and implement a comprehensive and person-centered intervention plan as part of an interdisciplinary team.

• Proceed with evaluation and fitting for hearing assistive technology systems to address central auditory deficits.

Assessment of CAPD

• CAPD cannot be diagnosed from one test alone, and there is no “gold standard” test battery.

• Assessment should not take longer than two hours.

CAPD Treatment

Environmental modifications

• Example - optimal seating in the classroom or at work

Compensatory strategies

• Example – requesting clarification when there is difficultly comprehending direction

Auditory training

• Therapy is customized based on areas with deficits

• See Table 20.3 on page 511 in text book for detailed examples.

Speech and language intervention as determined by the SLP

Why Teamwork is Important

• A cooperative team is essential for addressing auditory skill deficits in children

• AuDs provide a perspective for why a child may not interpret auditory information accurately

• SLPs offer insight on how language skills are affected by the breakdown in auditory-related skills.

Behavioral measures

identify auditory cognitive deficits

Dichotic listening

assesses hemispheric function and transfer of auditory information between hemispheres

Temporal processing/sequencing

assesses ability to interpret timing aspects

of acoustic stimuli

Low-redundancy speech

assesses ability to interpret degraded speech

Binaural interaction

how auditory input works together from both ears

Auditory discrimination

ability to identify frequency, intensity, and duration of phonemes

Electrophysiologic measures

identify true auditory sensory deficits along the

CNS

Monaural low-redundancy speech training

• a process-based auditory remediation

• process: auditory discrimination/closure

• decifict: decoding

• goal: train the listener to fill in missing or distorted auditory information

• activities: vocabulary building enrichment, phonemic awareness activities

Dichotic speech tests

• a process-based auditory remediation

• process: binaural integration/separation

• decifict: integration

• goal: designed so the listener can integrate information from both hemispheres

• activities: listening training, localization training, speech-in-noise training

temporal processing/pattern

• a process-based auditory remediation

• process: temporal resolution, frequency discrimination, intensity discrimination, duration discrimination, temporal ordering

• decifict: prosodic

• goal: designed to enhance the ability to recognize prosodic aspects of speech such as intonation, stress, and rhythm

• activities: prosody training, self-auditorization, keyword extraction, word meaning