Auditory processing disorder (APD), rarely known as King-Kopetzky syndrome or auditory disability with normal hearing (ADN), is a neurodevelopmental disorder affecting the way the brain processes sounds. 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. It is highly prevalent in individuals with other neurodevelopmental disorders, such as attention deficit hyperactivity disorder, autism spectrum disorders, dyslexia, and sensory processing disorder. The American Academy of Audiology notes that APD is diagnosed by difficulties in one or more auditory processes known to reflect the function of the central auditory nervous system. It can affect both children and adults. Although the actual prevalence is currently unknown, it has been estimated to be 2–7% in children in US and UK populations. APD can continue into adulthood. Cooper and Gates (1991) estimated the prevalence of adult APD to be 10 to 20%. It has been reported that males are twice as likely to be affected by the disorder as females, and that prevalence is higher in the elderly and increases with age. Neurodevelopmental forms of APD are differentiable from aphasia in that aphasia is by definition caused by acquired brain injury, but acquired epileptic aphasia has been viewed as a form of APD. Signs and symptoms Many people experience problems with learning and day-to-day tasks with difficulties over time. Adults with this disorder can experience the signs and symptoms below: talk louder than necessary talk softer than necessary have trouble remembering a list or sequence often need words or sentences repeated have poor ability to memorize information learned by listening interpret words too literally need assistance hearing clearly in noisy environments rely on accommodation and modification strategies find or request a quiet work space away from others request written material when attending oral presentations ask for directions to be given one step at a time Relation to attention deficit hyperactivity disorder It has been discovered that APD and ADHD present overlapping symptoms. Below is a ranked order of behavioral symptoms that are most frequently observed in each disorder. Professionals evaluated the overlap of symptoms between the two disorders. The order below is of