Central Auditory Processing Disorder
Central auditory processing refers to the efficiency and effectiveness by which the central nervous system utilizes auditory information. A central auditory processing disorder (CAPD) occurs when there are deficiencies in the central auditory nervous system and the neurobiologic activity that underlies that processing. A central auditory processing disorder may co-exist with other disorders such as attention deficit hyperactivity disorder, language impairment, and learning disability.
Several skills are dependent on normal processing of auditory information in the central nervous system, including:
Sound localization and lateralization
Temporal aspects of audition
Auditory performance with degraded or competing acoustic signals
Individuals with Central Auditory Processing Disorders
A person with a CAPD has trouble making sense out of what they hear, despite normal hearing sensitivity. Thus, they may act like someone who has a hearing loss. The individual or their parents or teachers may notice the following behaviors:
- Difficulty understanding speech in the presence of background noise or in rooms with high reverberation
- Decreased attention to or inconsistent/inappropriate responses to auditory information or requests made by others
- Frequent requests for repetition and/or rephrasing of information
- Difficulty comprehending and following rapid speech.
- Breakdown in following directions or remembering auditory instructions
- Difficulty in detecting changes in speech that impact the understanding of sarcasm or jokes
- Poor singing, musical ability, and/or appreciation of
- Poor phonological/phonemic awareness
- Poor auditory discrimination skills for speech sounds
- Difficulty localizing the source of an auditory signal.
- Weakness in speech-language or psychoeducational tests with an emphasis on auditory comprehension or auditory related skills
- Difficulty learning a foreign language or novel speech materials, especially technical language
- Academic difficulties, including reading, spelling,
and/or learning problems
The above characteristics may also be noted in other co-morbid conditions. As such, the complexity of CAPD requires the need for a collaborative approach via a multidisciplinary team.
Assessment for Central Auditory Processing Disorders
The assessment and diagnosis of CAPD is completed by an audiologist, although evaluations from other disciplines, such as speech-language pathology and psychology, are needed to rule out any co-morbid conditions that may contribute to listening difficulties. Behavioral test batteries for CAPD should include both verbal and non-verbal tasks that assess different levels and regions of the central auditory nervous system and a variety of auditory mechanisms. These procedures may include, but are not limited to, assessing the following auditory processes:
- Sound localization and lateralization
- Auditory discrimination
- Auditory temporal processing
- Auditory pattern processing
- Dichotic listening
- Auditory performance in competing acoustic signals
- Auditory performance with degraded acoustic signals