Auditory processing disorder (APD) 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 recognizing and interpreting sounds, especially the sounds composing speech. It is thought that these difficulties arise from dysfunction in the central nervous system. In the majority of cases of developmental APD, the cause is unknown. There is, however, no consensus as to which tests should be used for diagnosis. Experts attempting to define diagnostic criteria have to grapple with the problem that a child may do poorly on auditory tests for reasons other than poor auditory perception: for instance, failure could be due to inattention, difficulty in coping with task demands, struggling with semantic density or specificity, or limited language ability.
A diagnosis of Auditory Processing Disorder is controversial and not formally recognized among psychologists and psychiatrists, since there is no known agreed upon etiology (scientifically identifiable cause) and no set of tests to diagnose it. For a psychologist like myself, formally recognized conditions consist of those which are listed in the DSM-5 Manual (Diagnostic and Statistical Manual of Mental Disorders), the primary reference text and ‘Bible’ for mental health professionals. The term Auditory Processing Disorder arose from auditory and speech pathologists, and has a generally recognized meaning that a student has a challenge with processing verbal information, a challenge which is not due to a hearing impairment.
In the case of students who struggle to efficiently process auditory/verbal information, I find this is basically always due to one of two causes: moments of inattention, or difficulty processing dense semantic information efficiently. The former is part and parcel of ADHD whereas the latter occurs in students with dyslexia. . In fact, research shows that 84% of children with APD have confirmed or suspected ADHD.
A challenge in the field of learning disabilities is a lack of full consensus across professionals; psychologists and speech pathologists can assess the same student and reach seemingly different conclusions regarding the same symptoms. It is like the old idiom about a blind man touching different parts of an elephant; we describe different facets of the same student and reach seemingly different conclusions. This is challenging for parents and students alike and does not help consumers understand the etiology of the condition described. As a psychologist, I base my assessment on the conditions in the DSM-5 and explain the known sources of these to students and families. That said, reaching a level of diagnostic certainty is not always possible, though often it is. Consumers appreciate their conditions being demystified and having the opportunity to make better sense of their symptoms.