Behavioral performances in participants with phonological dyslexia and different patterns on the N170 component.

Adults with phonological dyslexia and controls performed a lexical decision task while ERPs were recorded in the occipitotemporal pathway. Based on N170 durations, two subgroups were formed: dysl1 showing longer N170 durations and dysl2 showing normal N170 durations. While the dysl1 subgroup had poorer accuracy for infrequent words and pseudo-words, the dysl2 group responded more slowly than controls to pseudo-words. N170 amplitudes were larger in the left hemisphere for controls irrespective of items. In the dysl1 subgroup, N170 amplitudes were larger in the left hemisphere than the right for words but not for pseudo-words, a sign of hemispheric compensation, while in the dysl2 subgroup signs of bilateralization were observed. Moreover, in the dysl1 subgroup, P100 amplitudes were smaller than controls. These results indicate different behavioral profiles of dyslexics with different patterns of P100 and N170 components. The ERP changes may be due to different behavioral strategies employed by each subgroup, logographic in dysl2 and phonological in dysl1.