Evolving concepts of developmental auditory processing disorder (APD): A British Society of Audiology APD Special Interest Group ‘white paper’
Abstract Children with listening difficulties, but normal audiometry, may be diagnosed with APD. The diagnosis is typically based on poor performance on tests of perception of both non-speech and speech stimuli. However, non-speech test results correlate only weakly with evaluations of speech-in-noise processing, cognitive skills, and caregiver evaluations of listening ability. The interpretation of speech test results is confounded by the involvement of language processing mechanisms. Overall, listening ability is associated more with higher-level, cognitive and analytic processing than with lower-level sensory processing. Current diagnosis of a child with APD, rather than another problem (e.g. language impairment, LI), is determined more by the referral route than by the symptoms. Co-occurrence with other learning problems suggests that APD may be a symptom of a more varied neurodevelopmental disorder. Alternately, APD has been proposed as a cause of language-based disorders, but there is no one-to-one mapping between listening and language among individuals. Screening for APD may be most appropriately based on a well-validated, caregiver questionnaire that captures the fundamental problem of listening difficulties and identifies areas for further assessment and management. This approach has proved successful for LI, and may in future serve as a metric to help assess other, objective testing methods. Foreword Auditory processing disorder (APD) has a long (>?30 years) and controversial history. The controversies concern absolutely fundamental issues: the definition of APD, its neural basis, test validity and standardization, differentiation from other disorders, and even whether it exists as an independent disorder (Jerger, 2009). To evaluate and interpret the scientific evidence on APD, and to advise the audiology profession, the British Society of Audiology (BSA) established a Special Interest Group (BSA SIG) on APD in 2003. That group has recently published two key documents, a ?Position Statement? and a ?Management Overview? (BSA, 2011, a,b. See www.thebsa.org.uk ?Procedures and Publications?). In formulating the new position statement, it became clear to the group that several significant differences were developing between their interpretation of the evidence concerning APD and that of the American Academy of Audiology (AAA), as stated in their recently published ?Guidelines for the diagnosis, treatment and management of children and adults with central auditory processing disorder? (AAA, 2010). To address these differences, and borrowing from British Parliamentary procedure, the BSA SIG decided to develop a ?white paper?, a discussion document that could then receive an international set of commentaries from other research groups working on APD. An approach was made to the editor of the International Journal of Audiology who agreed to this suggestion. This paper, and the associated commentaries that follow, are the result.