Auditory processing disorder (APD), also known as central auditory processing disorder (CAPD) is an umbrella term for a variety of disorders that affect the way the brain processes auditory information. Individuals with APD usually have normal structure and function of the outer, middle and inner ear (peripheral hearing). However, they cannot process the information they hear in the same way as others do, which leads to difficulties in recognizing and interpreting sounds, especially the sounds composing speech. It is thought that these difficulties arise from dysfunction in the central nervous system (i.e., brain). APD has been referred to as dyslexia for the ears.
APD does not feature in mainstream diagnostic classifications such as the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). APD is not a coherent syndrome with clear diagnostic criteria. Rather, it is a label applied when a person has difficulties in recognizing and interpreting sounds that are not due to peripheral hearing loss.
APD can affect both children and adults, although the actual prevalence is currently unknown. It has been suggested that males are twice as likely to be affected by the disorder as females, but there are no good epidemiological studies.
