Language and Brain Lab, School of Education, Tel Aviv University, Israel.
Cortex. 2010 Sep;46(8):982-1004. doi: 10.1016/j.cortex.2009.08.007. Epub 2009 Aug 27.
Letter position dyslexia (LPD) is a deficit in the encoding of letter position within words. It is characterized by errors of letter migration within words, such as reading trail as trial and form as from. In order to examine whether LPD is domain-specific, and to assess the domain-specificity of the visual analysis system, this study explored whether LPD extends to number reading, by testing whether individuals who have letter migrations in word reading also show migrations while reading numbers. The reading of words and numbers of 12 Hebrew-speaking individuals with developmental LPD was assessed. Experiment 1 tested reading aloud of words and numbers, and Experiment 2 tested same-different decisions in words and numbers. The findings indicated that whereas the participants with developmental LPD showed a large number of migration errors in reading words, 10 of them read numbers well, without migration errors, and not differently from the control participants. A closer inspection of the pattern of errors in words and numbers of two individuals who had migrations in both numbers and words showed qualitative differences in the characteristics of migration errors in the two types of stimuli. In word reading, migration errors appeared predominantly in middle letters, whereas the errors in numbers occurred mainly in final (rightmost) digits. Migrations in numbers occurred almost exclusively in adjacent digits, but in words migrations occurred both in adjacent and in nonadjacent letters. The results thus indicate that words can be selectively impaired, without a parallel impairment in numbers, and that even when numbers are also impaired they show different error pattern. Thus, the visual analyzer is actually an orthographic visual analyzer, a module that is domain-specific for the analysis of words.
字母位置失读症（LPD）是一种在单词内编码字母位置的缺陷。它的特征是单词内字母迁移错误，例如将 trail 读成 trial，form 读成 from。为了检验 LPD 是否具有特定领域性，并评估视觉分析系统的特定领域性，本研究通过测试具有单词阅读中字母迁移的个体是否在阅读数字时也表现出迁移，来探究 LPD 是否扩展到数字阅读。测试了 12 名具有发展性 LPD 的希伯来语个体的单词和数字阅读。实验 1 测试了大声朗读单词和数字，实验 2 测试了单词和数字的相同-不同判断。研究结果表明，尽管患有发展性 LPD 的参与者在阅读单词时表现出大量迁移错误，但其中 10 人阅读数字时没有迁移错误，并且与对照组参与者没有区别。对在数字和单词中都有迁移的两名个体的单词和数字的错误模式进行更仔细的检查表明，两种类型刺激的迁移错误特征存在质的差异。在单词阅读中，迁移错误主要出现在中间字母中，而数字中的错误主要出现在最后（最右侧）数字中。数字中的迁移几乎只发生在相邻的数字中，但在单词中，迁移既发生在相邻字母中，也发生在非相邻字母中。因此，结果表明单词可以被选择性地损伤，而数字不会出现平行损伤，即使数字也受到损伤，它们也会表现出不同的错误模式。因此，视觉分析器实际上是一个特定于单词分析的正字法视觉分析器模块。
