Sequential information processing in children with and without auditory processing disorder

Background. It is a controversial issue whether sequential processing in children with auditory processing disorders (APD) is a unimodal auditory impairment. Patients and methods. Normal achieving controls (n=12; mean age: 101.1 months; SD 20.3) and children referred to clinical facilities for assessment including children with monosymptomatic APD (n=25; mean age: 90.8 months; SD 9.8), children with developmental language disorder (DLD]) + APD (n=11; mean age: 89.5 months; SD 14.9), children with dyslexia + APD (n=10; mean age: 113.8 months; SD 17.1) were compared using the subtest digit recall of the German version of the K-ABC (Melchers & Preu beta 2001) and the K-ABC subtest hand movements in the visual modality. Results. On average all groups tended to perform alike in visual sequential processing and memory (T-score>50). Normal controls (non-APD) showed on average the best test performance (T-score 57.4; SD 10.5), but the mean performance did not differ significantly from children with APD. All groups also presented on average normal test performance in the auditory modality however, children of the clinical groups were below the age mean (DLD + APD: T-W 43.1; SD 6.8; monosymptomatic APD: T-W 45.8; SD 9.8; dyslexia + APD: 46.7; SD5.8). Children with DLD + APD and those with monosymptomatic APD exhibited a significantly lower but not poor performance in auditory processing of sequences compared to their performance in visual sequential processing. The results of auditory and visual processing of sequences were significantly correlated in the clinical groups DLD + APD (0.58) and monosymptomatic APD (0.34), but not in the smallest group dyslexia + APD (0.48) and in normal achieving controls (0.32). Conclusion. On the basis of the results of the present study it may be concluded that a normal test performance on visual measure does not exclude a bimodal or pansensory seriation disorder in children with APD. It does, however, indicate the existence of a primary auditory sequential processing deficit, because at least the processing of phonological and visual stimuli was not separately carried out in children with DLD + APD.