Co-morbidity of auditory processing, language, and reading disorders
Purpose: We assessed co-morbidity of auditory processing disorder (APD) language impairment (LI), and reading disorders (RD) in school-aged children.
Method: Children (N = 68) with suspected APD and non-verbal IQ standard scores of 80 or more were assessed using auditory, language, reading, attention, and memory measures. Auditory processing tests included the Frequency Pattern Test (FPT), Dichotic Digit Test (DDT), Random Gap Detection Test (RGDT), masking level difference (MLD), and a monaural low redundancy speech test (compressed and reverberant words). The Clinical Evaluation of Language Fundamentals Fourth Edition was used to assess language abilities (including auditory memory). Reading accuracy and fluency and phonological awareness abilities were assessed using the Wheldall Assessment of Reading Passages and the Queensland Inventory of Literacy. Attention was measured using a continuous performance test.
Results: Seventy two percent of the children had APD based on these test results. Most of these children (25%) had difficulty with the FPT bilaterally. A further 22% had difficulty with the FPT bilaterally and had right ear deficits for the DDT. About half of the children (47%) had problems in all three areas (APD;LI;RD); these children had the poorest FPT scores. More had APD/RD, or APD/LI, than APD, RD, or LI alone. There were modest correlations between FPT scores and attention and memory and between DDT scores and memory.
Conclusions: LI and RD commonly co-occur with APD. Attention and memory are linked to performance on some auditory processing tasks, but only explain a small amount of the variance in scores. Comprehensive assessment across a range of areas is required to characterize the difficulties experienced by children with APD.