Intervention for auditory processing disorder (APD) is most effective when speech-language pathologists and audiologists play a key role in assessment and treatment, with additional input from an interdisciplinary team that includes teachers, parents, physicians, and psychologists.
The area of APD is very broad, encompassing divergent opinions among clinical audiologists, and assessment procedures that result in a diagnosis of APD vary widely. Audiologic testing procedures for APD require memory and language concept knowledge to accurately respond. For example, in a dichotic listening task, an audiologist might ask a child to repeat the first word heard in the left ear. This requires a child to know serial order number concepts as well as left and right, while retaining the words in memory to recall upon demand. A child with a significant language disorder or attention problem might fail an auditory processing assessment battery due to language problems rather than auditory perceptual difficulties.
Providing treatment for "auditory processing" could include anything and everything that is involved with "the ability to abstract meaning from an acoustic stimulus" (Massaro, 1975). Audiologists specializing in APD are challenged to define parameters of the disorder, both behaviorally and neurologically. Differentiating aspects of APD is critical to effective intervention. The SLP who provides treatment needs to engage in additional evaluation procedures to determine a focus for intervention efforts.
The first aspect of auditory processing that should be examined is the acoustic integrity of the signal. While the audiologic evaluation can examine acoustic parameters in more detail-such as discrimination of tone duration, pitch, or loudness-the SLP should determine if the student is receiving an intact auditory signal. In other words, is the acoustic stimulus presented being received accurately by the listener? This can be informally assessed quickly and easily with a simple word repetition task. The SLP can ask the child to repeat a word or phrase immediately after hearing it. Nonsense words can be used if vocabulary development is a concern. Another easy method is to ask the student to point to items in the room that you name. If the student is successful in this task, then the general acoustic signal is being received as grossly intact.
The second step in follow-up assessment for an SLP would be to evaluate functional discrimination of the acoustic signal. This could involve tasks in auditory closure, auditory segmentation, auditory blending, or phoneme discrimination. Careful evaluation of a child's ability to manipulate and analyze acoustic features of an auditory signal will help determine specific treatment goals.
The third area of assessment for the SLP should be in the area of "language processing," or the ability to use the linguistic code to attach meaning to the acoustic signal. A child might be hearing an acoustic stimulus accurately, but not know what it means. For example, I can hear someone speak in a foreign language. I might be able to repeat what they said, but I have no idea what the content of their message is unless I know the language. The SLP must evaluate the child's ability to "decode" or attach meaning to the words received. Deficits could be more in the language realm of vocabulary acquisition, conceptual development, expressive word retrieval, or problem solving/reasoning.
These steps can be summarized by determining if the problem or breakdown occurs in:
To determine the appropriate and effective treatment goals, the SLP needs to engage in further assessment to differentiate the level of breakdown. This assessment can be conducted informally or formally, but intervention will only be as effective as the SLP's detective work to determine the crux of the problem. Once these areas have been evaluated, then intervention approaches and objectives can be determined. A differential analysis of the broad area of auditory processing disorders can result in more focused and effective treatment.
If the child experiences difficulty receiving the acoustic signal intact, then intervention would focus on enhancing or maximizing the signal while minimizing any signal disruptions. Many of the intervention methods for difficulty in signal detection will be compensatory in nature. Treatment might include improving the signal-to-noise ratio by reducing extraneous background noise, recommending an FM system, and encouraging seating near the instructor.
Direct intervention might include work on speechreading, auditory localization, auditory figure ground, attention techniques for careful listening, supplementing auditory presentation with visual reinforcement, and tape recording to allow repetition of a signal until "heard" accurately. Auditory memory also could be a component that needs to be addressed.
Signal manipulation difficulties will be addressed through treatment that emphasizes phonemic analysis skills. Treatment might include direct instruction and drill on phoneme identification, grapheme-phoneme correspondence, sound blending/phonemic synthesis, sound segmentation (e.g., first sound, last sound), rhyming, auditory closure, and auditory association.
Signal interpretation at a linguistic level enters a language realm, rather than an auditory realm. Treatment goals for interpretation problems might include teaching vocabulary labels, conceptual terminology, expressive language retrieval and organization, word meanings, and semantic relationships.