Abstract: Spelling difficulty is a major type of learning disorders. It refers to children who possess normal reading ability but have poor spelling ability. The orthographic representation deficit of children with spelling difficulties might stem from the global interruption of stroke processing, which is unique to Chinese characters. The current study aimed to examine whether two kinds of global interruption, namely global orthographic and phonological interruptions, would influence Chinese stroke processing respectively.
All participants came from the No. 1 primary school of Guyuan, Ningxia. 564 students took part in the screening, 32 of whom were diagnosed with spelling difficulties. Finally, 29 students with spelling difficulties and 30 healthy controls were chosen for further experiments. Their Raven scores, age, gender and grade were all matched.
Two 2 by 2 factor-designed experiments were conducted respectively. In the first experiment, a “+” was presented on the screen for 150 ms, followed by a target stroke; 300 ms later, a mask was presented for 300 ms, and then a probe pseudo-word was presented, which required the subjects to judge whether it contained the same stroke as the target. There were two kinds of probe pseudo-words with high and low global orthographic integrality. The second experiment was the same as the first one except that the two kinds of pseudo-words were of high and low global phonological accessibility.
The first experiment showed that the judging of stroke was influenced by global orthographic process, which applied to all children but more significantly to children with spelling difficulties. In contrast, the second experiment showed that the stroke judgment was prominently interrupted by disruption of global phonological accessibility for control group, but not significant for children with spelling difficulties.
Based on above findings, the authors proposed two hypotheses about spelling difficulties: global orthographic processing deficit (GOPD) hypothesis and stroke visual processing pattern (SVPP) hypothesis. According to the GOPD hypothesis, the global processing deficit would lead to two results: (1) In order to get legible global orthographic representation, children with spelling difficulties may heavily rely on orthographic process so that their stroke judgment would be much influenced by global orthographic processing. (2) Duration of global phonological accessibility would be prolonged. According to the SVPP hypothesis, the stroke judgment of children with spelling difficulties mainly depends on visual processing. This could also lead to two results: (1) Stroke judgment would be easily interrupted by global orthographic processing. (2) Children with spelling difficulties would not be affected by global phonological processing. However, the reliability of these two hypotheses needs further investigation

Key words: spelling difficulties, stoke processing, global interruption