Auditory Processing Disorder
Professionals began clinically assessing central auditory dysfunction in the 1950s. (C)APD is diagnosed using two primary types of tests: behavioral (psychosocial) and electrophysiological. APD can only be diagnosed by an audiologist that has been trained in the area. Behavioral tests for central auditory processing require that the individual be at least seven or eight years of age. While younger children can receive behavioral diagnostic testing, it should be done with extreme caution. Behavioral tests can be divided into two types: speech, or non-speech tests. While non-speech tests are being used more as of late, speech test stimuli are still more widely used. It is worth noting that there are psychometric limitations in many of the commonly used tests for central auditory processing. Professionals should choose their evaluation materials with that in mind. It is important to address possible comorbid and associated disorders during evaluation and management of APD. Goals for APD evaluation include indicating normal versus abnormal performance and to describe areas of strength and weaknesses in auditory performance. This is important when the clinician is coming up with intervention goals to target in therapy.
As was previously mentioned, there are two primary types of tests used for the diagnosis of (C)APD. The first battery of tests are the behavioral tests. Behavioral tests may include: tests of specific auditory processes, tests of temporal processes (The Gaps-in-Noise (GIN) Test, temporal sequencing tests), dichotic listening tasks, tests of monaural low-redundancy speech perception, tests of localization and lateralization and other binaural functions, auditory discrimination tests, and behavioral central auditory tests. Auditory electrophysiological tests evoke auditory responses from the auditory brainstem. These responses can be elicited using acoustic signals such as tone-bursts, clicks, and speech signals. Specific types of auditory electrophysiological tests include: Auditory Brainstem Response (ABR), Auditory Middle Latency Response (AMLR), and other cortical auditory evoked responses.
Intervention for (C)APD should begin as soon as it is diagnosed by a qualified professional. Intervention for APD often involves two components: bottom-up and top-down treatments. Bottom-up intervention involves auditory training skills remediation and environmental modifications. Environmental modifications are used to increase the clarity of the auditory signal or improve the listening environment. Improving the listening environment may involve using clear speech, assistive listening systems or improve the acoustics of the room). Top down intervention includes: educational intervention, central resource training, and accommodations made in the workplace or home environment. Bottom-up intervention is a more stimulus driven approach while top-down intervention involves a more strategy driven approach. The goal of both approaches is to build listening strategies and skills for the individual, to promote efficient allocation of language, memory, and attention, and to provide compensatory strategies and methods to minimize any deficits the individual may have. It is important that intervention for individuals having difficulty be undertaken by a multidisciplinary team that may include: audiologists, SLPs, teachers, psychologists, and parents. Also, treatment should be individualized to ensure that the intervention chosen is best for the individual taking diagnostic data, peer reviewed research and clinical expertise into account.
– Alexandra F.