Central Auditory Processing
University of Kansas Medical Center
State University College of New York at Fredonia
Central auditory processing (CAP) tends to be a confusing topic for many professionals and for the public. In part, people have difficulty understanding what CAP is because CAP disorder (CAPD) (a) can express itself in many ways, (b) is associated with many disorders, and (c) is evaluated by a variety of tests that often show little resemblance to one another. This chapter's purpose is to clarify what CAP is and to show how to divide the problem into its component parts. In this way, CAP is not only more understandable, but also quite predictable, and this knowledge gives us the ability to better remediate the auditory and related difficulties. When we take into account the large proportion of the central nervous system (CNS) devoted to auditory and auditory-related functions, it not surprising that so many academic and communicative problems are associated with CAPD (see also Leppänen et al., chap. 4, this volume).
In 1994, the American Speech-Language and Hearing Association (ASHA) convened a task force to develop a definition of CAPD. The report published in 1996 indicated that CAPD consists of preconscious events resulting in the inability to discriminate auditory patterns, localize sound, and understand speech with competing or degraded stimuli.
We define CAP as what we do with what we hear. Thus, CAPD is not a hearing problem (although it often resembles one), but rather what the CNS does to make what we hear most valuable and efficient. Hearing loss is closely associated with the peripheral auditory system (e.g., the middle