Evolving the concept of APD

Objective: To consider the evolving concept of auditory processing disorder (APD). Design: Narrative review and opinion piece. Study sample: Eight approaches to APD described in the literature and its definitions by ten societies or groups from around the world. Results: The dominant conceptualisation of APD remains one of disorders (or at least deficits) in the bottom-up processing of sound in the primary auditory nervous system that are not due to higher order (top-down) language or cognitive deficits. Challenges to this conceptualisation question the relevance of (bottom-up) AP to listening, learning and language. These challenges are rejected by some groups who maintain the dominant bottom-up conceptualisation of APD, but accepted by others who suggest APD be reconceptualised to include top-down processing of sound or attempts to define APD be de-emphasised in favour of a hierarchical approach to listening difficulties. Conclusions: To reconcile these challenges, the concept of APD could be better evolved by considering it as a spectrum disorder spanning from bottom-up AP to the top-down cognitive processes (particularly attention) that affect it.