Auditory processing is what happens as your brain identifies and interprets sound. Hearing is something that occurs when sound waves travel through the air and reach our ears. Once there, sound energy is transformed into electrical pulses: information our brains can interpret. When we speak of a Central Auditory Processing Disorder (CAPD or APD) or impairment, this means that a factor is present that has a negative effect on how someone processes and so interprets auditory information.
People with APD will have difficulties with the interpretation, retention, and retrieval of auditory information, in spite of the fact that they have normal peripheral hearing.
Besides making it difficult to develop speech and language skills, APD can have an adverse effect on reading and writing. It appears that APD is caused by neurological deficits.
Children with APD may not recognize small differences in word sounds, even when those sounds are spoken with careful clarity or at high volume. Such subtle differences can make verbal communication and understanding quite difficult. If you should ask a child with APD, “Explain how a cow and a cat are alike,” he may hear the words transposed, “Explain how a cat and a cow are alike,” or perhaps understand you to mean, “Explain how a couch and a hat are alike.” These ‘hearing’ issues crop up with greater frequency when the child is in a noise-filled environment or when he’s listening to complicated information. APD is sometimes referred to as ‘word deafness’.
Kids with APD often have accompanying learning difficulties such as ADD, dyslexia, language impairment, PDD, delayed development or autism. Figures vary as to just how often such learning disabilities coexist with APD. While 5 – 10% of school-aged children will be found to have APD, 45 – 75% of children with ADHD also experience APD (Riccio-et al., 1994; Tannock & Brown, 2000). Though learning issues are pervasive in kids with APD, most have normal intelligence and peripheral hearing.