Auditory Processing Disorder and Its Comorbidities: A Need for Consistency in Test Cutoff Scores.

Purpose No gold standard criteria exist for diagnosing developmental auditory processing disorder (APD). This study aimed to identify APD criteria, which are consistent with that used for comorbidities, and how comorbidities predicted APD. Method A retrospective study of 167 participants (males = 105, females = 62; age: 6-16 years; nonverbal IQ > 80) with suspected APD is presented. Five SCAN-3 tests evaluated auditory processing (AP). Comorbidities included attention-deficit/hyperactivity disorder, language impairment, and impaired manual dexterity, which were identified using percentile ≤ 5 in the Swanson, Nolan and Pelham parental rating scale; Children's Communication Checklist-2; and Movement Assessment Battery for Children-2, respectively. Results Percentiles ≤ 9, ≤ 5, and < 2 in two or more AP tests had sensitivities (specificities) of 76% (70.6%), 59.3% (76.5%), and 26% (82.4%), respectively, in predicting comorbidities, which were present in 150 of the 167 participants. The criterion of "≤ 9 percentile in two or more AP tests" (Approach I) diagnosed APD in 119 participants, and criterion "≤ 5 percentile in two or more AP tests or ≤ 5 percentile in one AP plus one or more measures of comorbidities" (Approach II) diagnosed 123. The combination of approaches diagnosed 128 participants (76.6%) with APD, of which 114 were diagnosed by each approach (89%). Language impairment and impaired manual dexterity, but not attention-deficit/hyperactivity disorder, predicted APD. Conclusions "Percentile ≤ 9 in two or more AP tests" or "percentile ≤ 5 in one AP plus one or more measures of comorbidities" are evidence-based APD diagnostic criteria. Holistic and interprofessional practice evaluating comorbidities including motor skills is important for APD.