Orthographic-phonological mapping impairments in Chinese children with developmental dyslexia: insights from an ERP investigation

In the realm of logographic writing systems, such as Chinese characters, orthographic transparency fundamentally differs from alphabetic languages, posing unique challenges for individuals with developmental dyslexia (DD). This study employed event-related potentials (ERPs) and a masked priming paradigm to investigate how Chinese children with DD compared to typically developing (TD) children in their utilization of orthographic-phonological mapping rules during the processing of pseudocharacters. The findings revealed noteworthy distinctions between TD and DD children. TD children exhibited a robust priming effect in radical priming, characterized by an enhanced N170 (100-200 ms) amplitude and a reduced P200 (200-350 ms) amplitude, whereas DD children did not display this differentiation. This observation parallels the difficulties faced by DD children in alphabetic languages. Furthermore, the study found a significant positive correlation between the N170 amplitude in the left posterior brain region of Chinese DD children and their orthographic performance: DD children with poorer orthographic awareness exhibited larger N170 amplitudes in this region. The present study sheds light on the challenges Chinese DD children encounter in processing regular sub-character routes, particularly evident in the early stages of orthographic processing. The orthographic deficits of DD children hinder their processing of Chinese orthography, resulting in increased cognitive demands.