Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Munich, Pettenkoferstr. 8a, 80336 Munich, Germany.
Institute of Psychology, University of Graz, Universitätsplatz 2/DG, 8010 Graz, Austria.
Clin Neurophysiol. 2018 Mar;129(3):526-540. doi: 10.1016/j.clinph.2017.12.010. Epub 2017 Dec 24.
In consistent orthographies, isolated reading disorders (iRD) and isolated spelling disorders (iSD) are nearly as common as combined reading-spelling disorders (cRSD). However, the exact nature of the underlying word processing deficits in isolated versus combined literacy deficits are not well understood yet.
We applied a phonological lexical decision task (including words, pseudohomophones, legal and illegal pseudowords) during ERP recording to investigate the neurophysiological correlates of lexical and sublexical word-processing in children with iRD, iSD and cRSD compared to typically developing (TD) 9-year-olds.
TD children showed enhanced early sensitivity (N170) for word material and for the violation of orthographic rules compared to the other groups. Lexical orthographic effects (higher LPC amplitude for words than for pseudohomophones) were the same in the TD and iRD groups, although processing took longer in children with iRD. In the iSD and cRSD groups, lexical orthographic effects were evident and stable over time only for correctly spelled words.
Orthographic representations were intact in iRD children, but word processing took longer compared to TD. Children with spelling disorders had partly missing orthographic representations.
Our study is the first to specify the underlying neurophysiology of word processing deficits associated with isolated literacy deficits.
在一致性拼写中，孤立性阅读障碍（iRD）和孤立性拼写障碍（iSD）与读写障碍（cRSD）一样常见。然而，孤立性与读写障碍相比，其潜在的单词处理缺陷的具体性质尚未得到很好的理解。
我们在 ERP 记录期间应用了语音词汇决策任务（包括单词、假同形同音字、合法和非法的伪词），以研究 iRD、iSD 和 cRSD 儿童与正常发育（TD）9 岁儿童相比，词汇和亚词汇单词处理的神经生理相关性。
与其他组相比，TD 儿童对单词材料和违反正字法规则的反应表现出更强的早期敏感性（N170）。在 TD 和 iRD 组中，词汇正字法效应（单词的 LPC 振幅高于假同形同音字）相同，尽管 iRD 儿童的处理时间更长。在 iSD 和 cRSD 组中，只有正确拼写的单词才能显示出词汇正字法效应，且随着时间的推移，这种效应保持稳定。
iRD 儿童的正字法表征完好，但与 TD 相比，单词处理时间更长。拼写障碍儿童的正字法表征部分缺失。
本研究首次明确了与孤立性读写障碍相关的单词处理缺陷的潜在神经生理学基础。
