Impaired non-speech auditory processing at a pre-reading age is a risk-factor for dyslexia but not a predictor: An ERP study

Impaired auditory sensitivity to amplitude rise time (ART) has been suggested to be a primary deficit in developmental dyslexia. The present study investigates whether impaired ART-sensitivity at a pre-reading age precedes and predicts later emerging reading problems in a sample of Dutch children. An oddball paradigm, with a deviant that differed from the standard stimulus in ART, was administered to 41-month-old children (30 genetically at-risk for developmental dyslexia and 14 controls) with concurrent EEG measurement. A second deviant that differed from the standard stimulus in frequency served as a control deviant. Grade two reading scores were used to divide the at-risks in a typical-reading and a dyslexic subgroup. We found that both ART- and frequency processing were related to later reading skill. We however also found that irrespective of reading level, the at-risks in general showed impaired basic auditory processing when compared to controls and that it was impossible to discriminate between the at-risk groups on basis of both auditory measures. A relatively higher quality of early expressive syntactic skills in the typical-reading at-risk group might indicate a protective factor against negative effects of impaired auditory processing on reading development. Based on these results we argue that ART- and frequency-processing measures, although they are related to reading skill, lack the power to be considered single-cause predictors of developmental dyslexia. More likely, they are genetically driven risk factors that may add to cumulative effects on processes that are critical for learning to read. (C) 2012 Elsevier Ltd. All rights reserved.