Selected Performances in Speech Perception in Children with APD

Abstract

Background: The ability to detect phonemes in spoken language (phonological processing) is equally important for first and secondary language acquisition (reading, spelling, orthography). Nevertheless, it is a subject of some controversy whether psychometric tests of auditory verbal stimuli (linguistic load) are to take in account in the diagnostics of (central) auditory processing disorders (C)APD. Methods: Data in phonological synthesis and in verbal auditory closure, obtained from a research database of children who were audiologically and psychologically diagnosed as with auditory processing deficits, were analyzed retrospectively. These data were collected by a clinical psychologist in the diagnostic setting, who administered the subtests Sound Blending and Auditory Closure out of the German version of the Illinois Test of Psycholinguistic Abilities. Participants: Three clinical groups: n = 51 with monosymptomatic APD; n = 33 with APD + developmental language impairment; n = 15 with APD and developmental dyslexia and one control group (typically developing children without clinical developmental disorders). Inclusion criteria: normal hearing status and nonverbal intelligence, monolingual German-speaking, no suspicion of attention deficit hyperactivity disorders and visual perception disorders and scoring : 2 SDs below the reference mean in at least 2 auditory symptoms. Results: The controls showed the best performance in "Sound Blending" (T-score 49.2; SD 8.8), followed by children with monosymptomatic APD (T-score 48.0; SD 9.5) and children with co-morbid conditions (APD + developmental dyslexia: T-score 45.9; SD 6.0; APD + language impairment: T-score 44.4; SD 8.7). The differences between the groups did not reach statistical significance. Test scores in "Auditory Closure" were consistently poorer in the APD-groups (children with monosymptomatic APD: T-score 50.9; SD 8.8; children with APD + developmental dyslexia: T-score 49.6; SD 7.7; children with APD + developmental language impairment: T-score 47.1; SD 10.5) than for the normal group (T-score 54.9; SD 7.5). None of the groups performed any differently from the controls. Conclusions: Because the acoustic-verbal automatic dimensions of sound blending and auditory closure did not differentiate the 4 study groups, experts should renounce of them in the diagnostics of (C)APDs.