Characteristics of auditory processing disorder in primary school-aged children

Abstract

The aims of this research were to identify and compare auditory processing, speech intelligibility, cognitive, listening, language and communication abilities in (i) typically developing, mainstream school (MS) children (n = 122) for direct comparison with (ii) children presenting to clinical services with auditory processing disorder (APD) (n = 19) or specific language impairment (SLI) (n = 22), and in (iii) a large population sample (n = 1469) who were categorised by their functional listening and communication abilities according to parental report rather than clinical diagnosis. All had normal hearing sensitivity. The clinically referred APD and SLI groups shared many behavioural characteristics across the broad range of measures. Both clinical groups significantly underperformed compared to the MS children, and the APD and SLI groups were virtually indistinguishable. This suggests diagnosis was based more on the referral route than on the actual differences. There was little association of auditory processing deficits with listening or language problems in either the clinical or the population sample after accounting for nonverbal IQ. The only exceptions were backward masking and frequency discrimination, the AP tests with the highest cognitive load. Poor general cognitive abilities were evident in those children with listening or language problems. These results suggest that top-down processing influences listening and language more than bottom-up sensory processing. It is argued that the term APD is a misnomer and should be renamed listening impairment. The co-occurrence of APD, or listening impairment, with both language impairment and autistic behaviours in the clinical and population samples suggests that APD is not a discrete and categorical disorder. Instead, APD as it is currently conceptualised, is dimensional, positioned more towards the language than the autistic extreme. Children with listening impairment who attend Audiology or ENT clinics should be screened for functional everyday measures of language and autistic behaviours to ensure appropriate onward referrals