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Talk;infancy

Thursday stream 2 Session 09.00 - 11.10 Length 25 minutes

Event-related potentials and consonant differentiation in newborns with a familial risk for dyslexia

T. Guttorm , P. H. T. Leppanen and H. Lyytinen

Department of Psychology, University of Jyväskylä, Finland (2) Center for Molecular and Behavioral Neuroscience, Rutgers University, USA tguttorm@psyka.jyu.fi

Abstract

We measured ERPs generated by synthetic consonant-vowel syllables (/ba/, /da/, /ga/) from 26 newborns with a familial risk for dyslexia and 23 control infants participating in the Jyväskylä Longitudinal Study of Dyslexia (JLD). The stimuli were presented with equal probability and with long interstimulus intervals of 3010 to 7285 ms. An analysis of average ERPs on the basis of principal component analysis revealed latency windows during which groups differed significantly. Between 50 and 170 ms there was an early obligatory response where the responses of the at-risk group to /ga/ at the right hemisphere were more positive than those of the control group. Also between 540 and 630 ms the responses to /ga/ differed between groups at the right hemisphere: the responses were positive in the at-risk group, and negative in the control group. Between 740 and 940 ms the responses of the control group to /da/ at the posterior electrode sites were less negative than those of the at-risk group. These results indicate that the cortical electric activation generated by speech elements is different between children with and without a risk for dyslexia already immediately after birth. Keywords: brain event-related potentials, newborns, developmental dyslexia, auditory speech processing, consonant differentiation