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Event Related Potentials (ERPs) from thirty children (9-13 years old); fourteen of whom were dyslexic and sixteen normal-reading controls, were recorded during the performance of a memory scanning task. Visually presented stimuli consisted of either digits (lexical) or unfamiliar (non-lexical) characters. The subjects had to indicate whether a probe stimulus was a member of a preceding memorized set, or not. The memorized sets included 1, 2 or 3 items. Performance accuracies were significantly lower and reaction times longer in the dyslexic group. The significant Group x Lexicality interaction demonstrated P3 amplitudes which were smaller to lexical compared to non-lexical stimuli in dyslexics compared to skilled readers. Brain activity in response to the probes was more prominent over the right scalp in dyslexics, in contrast to controls that had left side prominence. The results suggest that dyslexic children relate to the physical features of stimuli as opposed to skilled readers, who rely more on the linguistic features of the stimuli. We suggest that remembering visually presented items in dyslexics involves different cognitive strategies and brain structures compared to skilled readers.

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The assumption that specific learning disabilities are not causally related to emotional disturbances is crucial for the cognitive research approaches that endeavor to isolate specific malfunctioning cognitive-computational processes. Because there are conflicting data regarding the emotional status of subjects with learning difficulties, the purpose of this study was the evaluation of the emotional status of subjects with specific learning difficulties in comparison with that of subjects from several relevant control groups. The HSCL-90 profiles of 38 subjects suffering developmental dyslexia, 28 subjects with subjective complaints regarding general concentration and reading comprehension difficulties, and 23 psychiatric patients were compared with those of 44 skilled readers without any known emotional difficulties. All subjects were adolescents and young adults (age range = 15 to 23). A cluster analysis of subjects' HSCL-90 profiles did not reveal any significant differences between subjects with dyslexia and control subjects. Both groups, on the other hand, were easily differentiated from psychiatric patients. Subjects with severe deficits in their ability to remember details of a text, and with subjective complaints regarding concentration difficulties, tended to generate emotional profiles that testify to a high level of anxiety. Although these subjects, as well as individuals with dyslexia, may be regarded at the functional level as inefficient readers, the two groups seem to clearly differ regarding the failure factors that underlie their phenotypic difficulties.