Banai Karen, Ahissar Merav
Department of Neurobiology, Hebrew University of Jerusalem, Jerusalem, Israel.
Audiol Neurootol. 2004 Nov-Dec;9(6):328-40. doi: 10.1159/000081282. Epub 2004 Oct 1.
Substantial difficulties in performing simple auditory discriminations were previously found in some individuals with a specific reading disability but not in others. This high variability in psychoacoustic performance raises the question of whether this difficulty is related to the reading deficit. Addressing this question, we compared adult dyslexics with and without difficulty in simple auditory discriminations, using 2-tone frequency discrimination as our probe. The distribution of their frequency discrimination scores was bimodal. On this basis, we divided our participants into subgroups having either poor or adequate psychoacoustic performance. Only dyslexics with poor psychoacoustic scores had significantly impaired verbal working memory compared to their matched controls. Furthermore, and only in this subgroup, working memory scores were correlated with both cognitive abilities and reading-related tasks. Consistent with the hypothesis that in this subgroup poor working memory impedes performance in a broad range of academically related tasks, we found that the majority of dyslexics in this subgroup had more extensive academic difficulties and consequently needed special support in schools. We propose that dyslexics with poor psychoacoustic abilities form a distinct subtype of dyslexia in which the core deficit is not specific to phonological components. For these individuals, poor verbal working memory may be the main impediment to success in academic environments.
先前发现，一些患有特定阅读障碍的个体在进行简单听觉辨别时存在很大困难，而另一些人则没有。心理声学表现的这种高度变异性引发了一个问题，即这种困难是否与阅读缺陷有关。为了解决这个问题，我们以双音频率辨别作为测试指标，比较了在简单听觉辨别方面有困难和没有困难的成年阅读障碍者。他们的频率辨别分数分布呈双峰状。在此基础上，我们将参与者分为心理声学表现差或良好的亚组。与匹配的对照组相比，只有心理声学分数低的阅读障碍者的言语工作记忆有显著受损。此外，且仅在这个亚组中，工作记忆分数与认知能力和阅读相关任务均相关。与该亚组中工作记忆差会阻碍广泛的学业相关任务表现这一假设一致，我们发现这个亚组中的大多数阅读障碍者有更广泛的学业困难，因此在学校需要特殊支持。我们提出，心理声学能力差的阅读障碍者构成了阅读障碍的一个独特亚型，其核心缺陷并非特定于语音成分。对于这些个体而言，言语工作记忆差可能是在学术环境中取得成功的主要障碍。
