On differentiating auditory processing disorder (APD) from attention deficit disorder (ADD): an illustrative example using the Cattell-Horn-Carroll (CHC) model of cognitive abilities.

To clarify the distinction between Auditory Processing Disorder (APD) and Attention Deficit Disorder (ADD) using the CHC Model. A cross-sectional study compared responses of caregivers about their children's behaviour to identify characteristics of APD (CHC Model) and ADD (DSM-5). Caregivers, mostly mothers (92%), of 149 children (M 61%; F 39%) aged from 6 to 16 years, referred for "Auditory Processing Assessment" of their child, were shown an A4 card displaying the characteristics of AP from the CHC Model on one side, and of ADD from DSM-5 on the other. Both sides were untitled. For each side, caregivers were asked if the characteristics were true of their child using a Conners-type four-point scale. The majority of children were rated by caregivers as displaying characteristics of ADD, rather than an APD problem. Comparing problems with AP vs. problems with ADD gave: Wilcoxon  = 9.71;  = 4.86,  < 0.001. The finding that most children referred for an AP Assessment showed characteristics of ADD was surprising. Given the continuing audiological controversies about the nature of AP and about differentiating AP disorders from ADD, the CHC Model offers a different and informative perspective.