[(Central) Auditory Processing Disorders in Childhood--a Chimera or are Useful Clinical Diagnostic Tests Missing?]

(Central) Auditory Processing Disorders (C)APD are becoming ever more diagnosed in children, though there is no agreement on diagnostic markers (gold standard for (C)APD diagnosis). In Germany, the diagnostics of (C)APD in the paediatric population is based on test measurements including phonological processing rather than on a valid theoretical model to guide clinicians. The evaluation of the clinical significance of central auditory functions as well as the number of the behavioural tests which should be performed are left to the diagnostician.

The present study reviewed retrospectively test scores from a health care research database containing 167 children suspected of having a (C)APD. A total of 51 children participated in the study: 39 children identified with monosymptomatic (C)APD (on the basis of commonly used (C)APD tests with scores > or = 2 SDs below the mean on at least 2 tests) and 12 children who did not receive a (C)APD diagnosis (non-(C)APD). A stepwise discriminant analysis was performed with the five phonological measures of the psychological (C)APD-diagnostics in the German language: Nonword repetition by the Mottier-Test; the subtest "Recall of sentences" by the Heidelberger Sprachentwicklungstest for Language Development; "Digit Recall" by the German version of the K-ABC-subtest; "Auditory Closure" and "Sound Blending" by the subtests of the German version of the Illinois Test of Psycholinguistic Abilities. Next the discriminant function of the model was examined.

Performance in the normed tests (K-ABC Digit Recall: T-score 44.2, p = 0.0029; Sentence Recall: T-score 42.4, p = 0.0002; Auditory Closure: T-score 49.9, p = 0.0130; Sound Blending: T-score 47.2 p = 0.0121) and in nonword repetition (Mottier: 15.9 raw scores, p < .0001) was on average significantly reduced in the (C)APD group compared to the non-(C)APD-group, although the mean test results in the standardized tests were in the norm range. Only nonword repetition (F = 21.05; R (2) = 0.30; p < 0.0001) and recall of sentences (F = 3.74; R (2) = 0.07; p = 0.059) differentiated significantly in both groups. The posterior probability to classify the children was 80 % respectively the error-rate estimate was 20 %.

Children with (C)APD have a diminished temporal processing and perception ability which expresses itself in the limited capacity of their phonological short-term memory. A success in the discriminant function of no more than 80 % makes possibly aware of deficits in both validity and reliability of the diagnostic instruments.