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

We measured event-related potentials (ERPs) to synthetic consonant-vowel sy llables (/ba/, /da/, /ga/) from 26 newborns with familial risk for dyslexia and 23 control infants participating in the Jyvaskyla Longitudinal Study o f Dyslexia, The syllables were presented with equal probability and with in terstimulus intervals ranging from 3,010 to 7,285 ms. Analyses of averaged ERPs from the latencies identified on the basis of principal component anal ysis (PCA) revealed significant group differences in stop-consonant process ing in several latency ranges. At the latencies of 50-170 ms and 540-630 ms , the responses to /ga/ were larger and more positive than those to /ba/ an d /da/ in the right hemisphere in the at-risk group. Between 740 and 940 ms , the responses to /ba/ and /da/ differed between anterior and posterior el ectrode sites in the control group. These results indicate that the cortica l electric activation evoked by speech elements differs between children wi th and without risk for dyslexia even immediately after birth. Group-relate d effects at early and late latency ranges of ERPs suggest differences both in the early sound processing based on activation of afferent elements and in later phases of syllable encoding.