[Test Diagnosis of Processing Disorders (APD) in Primary School - a factor analytical study]

Our eclectic test battery for diagnosing Auditory Processing Disorders (APD) was applied in some pre-studies. Now, its underlying content structure should be examined by a factor analytic study.

Test results from 143 children with APD with an average age of 8.3 (SD 1.1) yrs. went into several Exploratory Factor Analyses (EFA; principal component analysis). Considering the underlying correlations of the test variables, and in consideration of the results of discriminant analysis pre-studies, an EFA with 12 (of a total of 16) diagnostic test variables seemed appropriate.

The Kaiser-Meyer-Olkin-measure of sampling adequacy was moderate middling to good (0.739). The determination of the optimal number of factors was based on the Kaiser criterion (eigenvalue > 1) and spoke in favour of four factors accounting for a cumulative variance of 63.7 %. A Scree-Test confirmed the four-component-solution. The component matrix showed that the loadings of the unrotated factors was mostly large on the first factor and therefore hardly to interpret. To obtain a better representation of the components, a Promax rotation was conducted. A clearly interpretable pattern of the rotated loadings resulted, forming these four components: phonematic processing; verbal-auditory memory; fundamental hearing processing, and a processing component of low redundance speech.

Based on these findings, a preliminary model of the central auditory processes of our APD-test battery was drafted as well as a contribution to construct validity made.