Auditory and cognitive abilities of children suspected of auditory processing disorder (APD)

Objective: Auditory processing disorder (APD) is typically characterised by difficulties in 'listening', particularly to speech in a noisy environment, despite normal peripheral function. In school-age children, APD has attracted considerable interest because of suspicions that it may lead to learning difficulties, especially affecting language and literacy. Here, we evaluated auditory and cognitive abilities in a group of children referred for an auditory evaluation on the grounds of a suspected auditory processing disorder (susAPD), and in age-matched children who were typically developing, in order to determine the extent to which any deficits in cognitive abilities could be related to auditory deficits.

Methods: A battery of auditory and cognitive tests was applied to 20 susAPD school-age children, all reported as having listening/hearing problems but performing within normal limits for standard audiometric assessments. Also tested was a group of 28 age-matched controls. The auditory tasks consisted of two simple same/different discrimination tasks, one using speech, and one nonspeech. The cognitive evaluation comprised a vocabulary test, a test of grammar and four non-verbal IQ measures. Symptoms of Attention Deficit Hyperactivity Disorder (ADHD) were assessed in the susAPD group through a standardised questionnaire.

Results: A significant proportion of susAPD children appeared to display genuine auditory deficits evidenced by poor performance on at least one of the auditory tasks, although about 1/3 had no detectable deficit. Children in the susAPD group scored consistently lower than the controls on cognitive measures that were both verbal (vocabulary and grammar) and non-verbal. Strikingly, susAPD children with relatively good auditory performance did not differ in cognitive ability from susAPD children with poor auditory performance. Similarly, within-group correlations between auditory and cognitive measures were weak or non-existent. Measures of ADHD did not correlate with any aspect of auditory or cognitive performance.

Conclusions: Although children suspected of having APD do show, on average, poorer performance on a number of auditory tasks, the presence or absence of an auditory deficit appears to have little impact on the development of the verbal and non-verbal skills tested here.