What is Central Auditory Processing?
Central auditory processing (CAP) or auditory processing (AP) is defined as the execution and coordination of specific auditory mechanisms in an interactive manner. This processing allows the central nervous system to detect, decode, synthesize and interpret auditory information. CAP disorder or dysfunction will act like an acoustic filter that distorts the reception and/or interpretation of verbal language. The process of differential diagnosis is very important because verbal information processing problems can result from: a central auditory processing problem; a language processing problem; a combination of both types of processing problems; and/or deficits in cognitive decision making or memory or attention or emotional factors.
How does the Audiologist test Central Auditory Processing?
In choosing formal behavioral measures, the audiologist will include tests that meet accepted psychophysical and scientific standards (e.g., sensitivity and specificity), control for higher-order confounds (e.g., limit language, attention and cognition loads), and are appropriate to the client (e.g., address presenting symptoms, age appropriate). Audiologic tests presented to the listener are pre-recorded on CDs. The test stimuli are presented via a clinical audiometer and through earphones. This method of presentation allows for the control of acoustic parameters. It also allows for separate testing of each ear as well as binaural presentation of different test items. Testing occurs in a sound attenuated suite and without any visual cues. These audiologic tests stress the auditory system more extensively than does a peripheral hearing evaluation. Informal behavioral tests may also be included and possibly electrophysiologic measures as well.