Miles J, Stelmack R M
University of Ottawa, Canada.
J Clin Exp Neuropsychol. 1994 Feb;16(1):43-64. doi: 10.1080/01688639408402616.
Three learning-disability (LD) subtype groups and a normal control group of children were compared in their visual event-related potentials (ERPs) to primed and unprimed words. The LD subtypes were defined by deficient performance on tests of arithmetic (Group A), reading and spelling (Group RS), or both (Group RSA). The primed words were preceded by pictures or spoken words having a related meaning, while unprimed words were preceded by non-associated pictures or spoken words. For normal controls, N450 amplitude was greater to unprimed words than to words primed by pictures and spoken words. For Group A, N450 amplitude was reduced by spoken-word primes, but not by picture primes, an effect that demonstrates a deficit in processing visual-spatial information. For Group RS and Group RSA, neither picture nor spoken-word primes reduced N450 amplitude. These effects can be understood in terms of deficiencies in processing auditory-verbal information. Normal controls displayed a greater left- than right-hemispheric asymmetry in frontal N450 amplitude to unprimed words, an effect that is consistent with the association of skilled reading with hemispheric specialization. This asymmetry was absent in the ERPs of all the LD subtypes. The distinct ERP effects for the groups endorses the value of defining LD subtypes on the basis of patterns of deficits in arithmetic and reading and spelling.
对三组学习障碍（LD）亚型儿童和一组正常对照组儿童进行了比较，观察他们对启动词和未启动词的视觉事件相关电位（ERP）。LD亚型根据算术测试表现缺陷（A组）、阅读和拼写测试表现缺陷（RS组）或两者皆有缺陷（RSA组）来定义。启动词之前会出现具有相关意义的图片或口语单词，而未启动词之前会出现不相关的图片或口语单词。对于正常对照组，未启动词的N450波幅大于由图片和口语单词启动的词。对于A组，口语单词启动会降低N450波幅，但图片启动则不会，这一效应表明在处理视觉空间信息方面存在缺陷。对于RS组和RSA组，图片和口语单词启动均未降低N450波幅。这些效应可以从处理听觉语言信息的缺陷方面来理解。正常对照组在额叶N450波幅上对未启动词表现出左半球比右半球更大的不对称性，这一效应与熟练阅读与半球特化的关联一致。所有LD亚型的ERP中均不存在这种不对称性。各小组不同的ERP效应支持了基于算术以及阅读和拼写缺陷模式来定义LD亚型的价值。
