Research Group ExpORL, Department of Neuroscience, KU Leuven, Leuven, Belgium.
Department of Cognitive Neuroscience and Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
Dev Sci. 2020 Jan;23(1):e12857. doi: 10.1111/desc.12857. Epub 2019 Jun 21.
There is an ongoing debate whether phonological deficits in dyslexics should be attributed to (a) less specified representations of speech sounds, like suggested by studies in young children with a familial risk for dyslexia, or (b) to an impaired access to these phonemic representations, as suggested by studies in adults with dyslexia. These conflicting findings are rooted in between study differences in sample characteristics and/or testing techniques. The current study uses the same multivariate functional MRI (fMRI) approach as previously used in adults with dyslexia to investigate phonemic representations in 30 beginning readers with a familial risk and 24 beginning readers without a familial risk of dyslexia, of whom 20 were later retrospectively classified as dyslexic. Based on fMRI response patterns evoked by listening to different utterances of /bA/ and /dA/ sounds, multivoxel analyses indicate that the underlying activation patterns of the two phonemes were distinct in children with a low family risk but not in children with high family risk. However, no group differences were observed between children that were later classified as typical versus dyslexic readers, regardless of their family risk status, indicating that poor phonemic representations constitute a risk for dyslexia but are not sufficient to result in reading problems. We hypothesize that poor phonemic representations are trait (family risk) and not state (dyslexia) dependent, and that representational deficits only lead to reading difficulties when they are present in conjunction with other neuroanatomical or-functional deficits.
目前,对于阅读障碍者的语音缺陷是否应归因于(a)语音表示不够具体,就像有阅读障碍家族风险的幼儿研究所表明的那样,或者(b)语音表示的获取受损,就像阅读障碍成人的研究所表明的那样,这一问题仍存在争议。这些相互矛盾的发现源于研究之间在样本特征和/或测试技术上的差异。本研究使用与之前在阅读障碍成人中使用的相同的多变量功能磁共振成像(fMRI)方法,来研究 30 名有阅读障碍家族风险的初学阅读者和 24 名无阅读障碍家族风险的初学阅读者的语音表示,其中 20 名后来被回顾性地分类为阅读障碍者。基于对不同 /bA/ 和 /dA/ 声音的聆听所引起的 fMRI 反应模式,多元体分析表明,在低家族风险的儿童中,这两个音素的基础激活模式是不同的,但在高家族风险的儿童中则没有。然而,无论其家族风险状况如何,在后来被分类为典型阅读者与阅读障碍者的儿童之间,都没有观察到组间差异,这表明语音表示较差是阅读障碍的风险因素,但不足以导致阅读问题。我们假设,语音表示较差是特质(家族风险)而不是状态(阅读障碍)依赖性的,并且只有在与其他神经解剖学或功能缺陷同时存在时,才会导致阅读困难。