Auditory Processing Disorders: Considerations for the Speech-Language Pathologist

Introduction

According to the American Speech-Language-Hearing Association (ASHA), central auditory processing disorder (CAPD/APD) is an observed deficiency in one or more of a group of mechanisms and processes related to a variety of auditory behaviors (1996). It involves difficulty in processing or interpreting verbal and/or nonverbal auditory stimuli usually in the absence of a peripheral hearing loss. APD may be associated with a lesion somewhere in the central auditory nervous system (CANS). According to Katz, it's "What we do with what we hear." (Katz, 1992).

The purpose of this article is to advocate early and efficient identification of auditory processing difficulties in children. A multidimensional team approach will be suggested for early analysis during kindergarten, with follow-up at second grade. The goal of this program is to identify, assess and successfully intervene at the earliest possible time with maximal positive impact for the child.

Children with APD

Children with APD may experience difficulties with: 1) localizing sound sources; 2) comprehending the meaning of environmental sounds; 3) discriminating among sounds and words; 4) reproducing the pitch, rhythm, and melody of music; 5) distinguishing important sounds from other sounds; or 6) combining syllables to form words and sentences (Barr, 1976), and other deficits may be apparent too.

APD can appear as the primary diagnosis or in combination with other disorders, such as learning disabilities, cluttering, or attention deficit disorder. Hearing loss (an acuity rather than perceptual problem) can complicate APD.

Chermak and Musiek (1997) estimated that APD affected approximately 3% of the school-age population. Goldberg (1998) maintained that auditory processing deficits impacted 5% of children. Incidence estimates are higher for the special education population.

The impact of APD upon language and language-dependent behaviors has been widely examined (Rampp, 1977; Cohen, 1980; Lasky and Cox, 1983; Sanger, Freed, and Decker, 1985; Tallal, 1990; Friel-Patti, 1994; Mody, Studdert-Kennedy and Brady, 1997; Cacace and McFarland, 1998). Although many clinicians agree that APD exists and can negatively affect language performance, there is disagreement concerning identification and intervention. Audiologists generally support a signal-based "bottom-up" model, while speech-language pathologists tend to advocate a "top-down" model. An integrated approach is consistent with the American Speech-Language-Hearing Association's (1996) inclusive definition of APD, as well as its recommendations for assessment and intervention.

Not all children who display APDs are diagnosed with APD. Many children with APD are misdiagnosed or not diagnosed at all. When APD presents as a secondary diagnosis, for example, to learning disabilities or attention deficit disorder, symptoms may be incorrectly associated with the primary diagnosis.