Pt. Ackerman et al., VISUAL EVENT-RELATED POTENTIALS OF DYSLEXIC-CHILDREN TO RHYMING AND NONRHYMING STIMULI, Neuropsychology, development, and cognition. Section A, Journal of clinical and experimental neuropsychology, 16(1), 1994, pp. 138-154
In a visual event-related potential (ERP) study, children diagnosed as
dyslexic in terms of both age and IQ discrepancy criteria were compar
ed with two contrast groups: poor for age (SLOW) readers and normal re
ading children with Attention Deficit Disorder (ADD). The children vie
wed 200 stimulus pairs and judged whether the second stimulus of each
pair rhymed with the first. The first stimulus was always a three-lett
er word, while half of the second stimuli were pronounceable nonsense
words and half were real words. Rhyme probability was 50%. The ERP wav
eforms of the dyslexics were significantly different from those of the
ADD group in showing less late negativity. The SLOW group's waveforms
more closely paralleled those of the ADD group. The major anomalous f
eature of the dyslexics' waveform was a pronounced late positive peak
(P500), which followed an attenuated N450 peak. Over all groups, the N
450 peak was sensitive to the rhyme manipulation, as has been found in
adults (Rugg, 1984a, 1984b). Real words and nonsense words produced s
imilar waveforms. Hemispheric effects were found but did not interact
with group. Results suggest non-automatic visual cognitive processing
of rhyme in dyslexics.