Auditory processing disorder (APD) can also be known as Central Auditory Processing Disorder (CAPD). It is a complex disorder that affects how the brain processes sound, most notably the sounds composing speech. Children with APD often do not recognise subtle differences between sounds in words, even when the words are loud and clear enough to be heard. They cannot process the information they hear in the same way as others as their ears and brain do not fully coordinate. They have basic difficulty of understanding any speech signal presented in less than optimal conditions.

Children with APD can have difficulty concentrating and reading when background noise is present. They will have difficulty understanding and remembering instructions. Their difficulties will impair the acquisition of reading and literacy skills. It is not a hearing impairment but a processing disorder. It prevents the sufferer processing auditory (verbal) information. Pupils benefit from small class sizes. In some cases pupils may need to wear an assisted listening device, such as an ‘iSense’, which helps with speech comprehension in noisy environments. APD is often misunderstood as many of the behaviours can also appear in other conditions. It is possible that it co-exists with other learning difficulties.