Reading proficiency and adaptability in orthographic processing: an examination of the effect of type of orthography read on brain activity in regular and dyslexic readers

Repetition Suppression for Familiar Visual Words Through Acceleration of Early Processing

The visual N1 (N170) component with occipito-temporal negativity and fronto-central positivity is sensitive to visual expertise for print. Slightly later, an N200 component with an increase after stimulus repetition was reported to be specific for Chinese, but found at centro-parietal electrodes against a mastoid reference. Given the unusual location, temporal proximity to the N1, and atypical repetition behavior, we aimed at clarifying the relation between the two components. We collected 128-channel EEG data from 18 native Chinese readers during a script decision experiment. Familiar Chinese one- and two-character words were presented among unfamiliar Korean control stimuli with half of the stimuli immediately repeated. Stimulus repetition led to a focal increase in the N1 onset and to a wide-spread decrease in the N1 offset, especially for familiar Chinese and also prominently near the mastoids. A TANOVA analysis corroborated robust repetition effects in the N1 offset across ERP maps with a modulation by script familiarity around 300 ms. Microstate analyses revealed a shorter N1 microstate duration after repetitions, especially for Chinese. The results demonstrate that the previously reported centro-parietal N200 effects after repetitions reflect changes during the N1 offset at occipito-temporal electrodes including the mastoids. Although larger for Chinese, repetition effects could also be found for two-character Korean words, suggesting that they are not specific for Chinese. While the decrease of the N1 offset after repetition is in agreement with a repetition suppression effect, the microstate findings suggest that at least part of the facilitation is due to accelerated processing after repetition.

The relations between reading and spelling: an examination of subtypes of reading disability

Three groups of reading-disabled children were found in studies of English, German, and French: a group with a double deficit in reading and spelling, a group with a single spelling deficit, and a more rarely reported group presenting a single reading deficit. This study set out to examine whether these groups can be found in adults, readers and spellers of Hebrew, which differs from the previously studied orthographies in many aspects. To this end, Hebrew-speaking adults with or without reading disability were administered various literacy and literacy-related tests. Results confirm the existence of the same three groups. While all shared a phonological deficit, subtle differences in phonological decoding ability and in speed of processing distinguished between the groups. The study therefore suggests that the previously reported associations and dissociations between reading and spelling are not restricted to English, German, or French and may not be only developmental in nature.

Functional neuroanatomy of developmental dyslexia: the role of orthographic depth

Orthographic depth (OD) (i.e., the complexity, consistency, or transparency of grapheme-phoneme correspondences in written alphabetic language) plays an important role in the acquisition of reading skills. Correspondingly, developmental dyslexia is characterized by different behavioral manifestations across languages varying in OD. This review focuses on the question of whether these different behavioral manifestations are associated with different functional neuroanatomical manifestations. It provides a review and critique of cross-linguistic brain imaging studies of developmental dyslexia. In addition, it includes an analysis of state-of-the-art functional neuroanatomical models of developmental dyslexia together with orthography-specific predictions derived from these models. These predictions should be tested in future brain imaging studies of typical and atypical reading in order to refine the current neurobiological understanding of developmental dyslexia, especially with respect to orthography-specific and universal aspects.