The contribution of AERPs (MMN and LDN) to studying temporal vs. linguistic processing deficits in children with reading difficulties

One of the factors responsible for the appearance of reading problems seems to be a difficulty in discriminating auditory stimuli presented in rapid succession, known as the ‘temporal processing hypothesis’. In this study automatic discrimination processes were evaluated in 31 children with reading difficulties and 24 control children between 4 and 8 years of age, using a passive oddball paradigm, in which syllables (/ba/ and /da/) and complex tones were presented. Analysis of the MMN component revealed significant differences between the groups only in the task involving linguistic stimuli, detecting longer latency of the component in the experimental group. The LDN component showed lower amplitudes and delayed latencies in the experimental group during the processing of both types of stimuli. These differences, however, were more marked in the task involving syllables, where a higher mean amplitude was observed in the experimental group than in the control group in the right hemisphere. The task involving complex tones also revealed differences between the groups at the frontal electrodes, indicating different maturative courses of the potential. The findings demonstrate the existence of a strongly pronounced preattentional auditory deficit during phonological processing, and also reveal important differences between the various stages of automatic information processing in children with and without reading disabilities.