| Auditory Perceptual Processing
(ICD 388.40; 389.14)
Auditory perceptual processing disorder is also referred to as an auditory perceptual problem, central auditory dysfunction or central auditory processing disorder (CAPD). It can be defined as difficulty in listening to or comprehending auditory information, especially under less optimal listening conditions (e.g., background noise). Simply put, it is a condition wherein a person does not process speech/language correctly. They may have difficulties knowing where sound has occurred and identifying the source of the sound or in distinguishing one sound from another. For example, “bear” may sound like “pear”, or “lair” may sound like “rare.” Children and adults with CAPD are diverse and have difficulty using auditory information to communicate and learn. CAPD is a deficit in the processing of auditory input, which may be exacerbated in unfavorable acoustic environments and is associated with difficulty in listening, speech, understanding, language development and learning (Jerger and Musick, 2000).
This disorder has been debated for many years among researchers in speech-language pathology. Due to the fact that no research has precisely and concretely identified areas of dysfunction in the brain or auditory pathway (nerve chain leading from the inner ear to the brain), some researchers question the disorder, and may call it a language disorder. However, audiological testing can determine the presence of CAPD. In terms of treatment, one researcher, Tallal, was able to demonstrate that this disorder could be addressed by practicing listening tasks including speech sound discrimination (repeatedly hearing the differences between sounds, such as “mud” vs “bud”). However, other researchers have been unable to replicate (reproduce) Tallal’s work, and thus the controversy for remediation remains unresolved.
This disorder is commonly seen in clinical practice, however, and Tallal’s program (called “Fast ForWord”) is one method that may be used to treat it. CAPD may cause delay in development of receptive and expressive communication skills. The disorder may be evident in a toddler or preschooler (i.e. failure to follow commands correctly, difficulty following conversation, difficulty reciting nursery rhymes), but it will be much more evident when the child enters elementary school; reading and writing difficulties are likely to emerge due to the child’s confusion regarding speech sounds. Early intervention (treating a child as soon as symptoms are evident) is important.
It is likely that research may find auditory perceptual processing disorder, or CAPD, to be a component in a broader language disorder. For example, as mentioned in the section on developmental language disorders, recent brain imaging research has shown that the brains of children with developmental language disorders are shaped differently in the “language areas.” Certain areas of the brain are dedicated to language processing, and these are the affected areas in children with language disorders.
An auditory perceptual processing disorder, or CAPD, may coexist with other disorders and must be differentiated. For example, there should be a differential diagnosis between CAPD and such issues as: normal variations in auditory processing skills, hearing loss, auditory neuropathy, hypersensitivity/hyposensitivity to sound, language impairment, learning disability, attention deficit, or cognitive impairments. An audiologist performs the evaluation for CAPD. A speech pathologist assesses language processing to assist in the differential diagnosis, determine types of problems present secondary to the dysfunction, and develop a treatment plan. Parents and classroom teachers are in key positions to help these professional in evaluation and treatment.