A dual-route perspective on poor reading in a regular orthography: An fMRI study

Abstract

This study examined functional brain abnormalities in dyslexic German readers who – due to the regularity of German in the reading direction – do not exhibit the reading accuracy problem of English dyslexic readers, but suffer primarily from a reading speed problem. The in-scanner task required phonological lexical decisions (i.e., Does xxx sound like an existing word?) and presented familiar and unfamiliar letter strings of existing phonological words (e.g., Taxi-Taksi) together with nonwords (e.g., Tazi). Dyslexic readers exhibited the same response latency pattern (words < pseudohomophones < nonwords) as nonimpaired readers, but latencies to all item types were much prolonged. The imaging results were suggestive for a different neural organization of reading processes in dyslexic readers. Specifically, dyslexic readers, in response to lexical route processes, exhibited underactivation in a left ventral occipitotemporal (OT) region which presumably is engaged by visual-orthographic whole word recognition. This region was also insensitive to the increased visual-orthographic processing demands of the sublexical route. Reduced engagement in response to sublexical route processes was also found in a left inferior parietal region, presumably engaged by attentional processes, and in a left inferior frontal region, presumably engaged by phonological processes. In contrast to this reduced engagement of the optimal left hemisphere reading network (ventral OT, inferior parietal, inferior frontal), our dyslexic readers exhibited increased engagement of visual occipital regions and of regions presumably engaged by silent articulatory processes (premotor/motor cortex and subcortical caudate and putamen).

Estudo piloto de validação do teste de identificação de sinais de dislexia (TISD)

“…A literatura mostra que crianças com sinais de DD possuem baixa proficiência tanto na decodificação quanto na codificação de palavras, provavelmente em razão dos déficits nas rotas supracitadas (Bergmann & Wimmer, 2008;Wimmer et al, 2010), situação que foi confirmada na presente pesquisa.…”

Lexical and sublexical orthographic processing: An ERP study with skilled and dyslexic adult readers

“…To provide a complete scenario, we further manipulated reading competence, so average and impaired dyslexic readers were compared as a between-subject factor. In the recent years, an increasing number of studies have provided evidence for a failure in orthographic processing in dyslexia, as expressed by behavioral (Araújo, Faísca, Bramão, Petersson, & Reis, 2014;Bergmann & Wimmer, 2008;Marinelli, Angelelli, Notarnicola, & Luzzatti, 2009;Marinus & de Jong, 2010) and neural correlates such as dyslexic vOT under activation (Hawelka, Gagl, & Wimmer, 2010;Maurer et al, , 2011van der Mark et al, 2009;Wimmer et al, 2010) or absent modulations of N1 responses to letter strings vs. symbols . Considering previous interpretations of impaired vOT orthographic processing in dyslexia as a tuning deficit at sublexical or lexical level van der Mark et al, 2009;Wimmer et al, 2010), we would expect a condition-specific group effect in N1 waveform as well, depending on whether this component reflects processing at these levels (since selective responses to letters in the N1 time window most likely originate from the inferior occipitotemporal cortex; Maurer & McCandliss, 2007;Tarkiainen, Helenius, Hansan, Cornelissen, & Salmelin, 1999).…”

Psicología cognitiva y neurociencias de la educación en el aprendizaje del lenguaje escrito y de las matemáticas

“…La intervención educacional puede facilitar esta asociación y el reconocimiento de las palabras. También Wimmer, H., Schurz, M., Sturm, D., Richlan, F., Klackl, J., Kronbichler, M. et al (2010), mediante la técnica de FMRI confirmaron que la deficiencia en la conexión visual ortográfica y fonológica observada en un grupo de disléxicos de habla alemana podría estar originadas en alteraciones en el desarrollo de algunos procesos neuropsicológicos subyacentes, fallas que pueden corregirse mediante la intervención psicopedagógica.…”