Hugdahl Kenneth, Heiervang Einar, Ersland Lars, Lundervold Arvid, Steinmetz Helmuth, Smievoll Alf Inge
Department of Biological and Medical Psychology, University of Bergen, Arstadveien 21, N-5009 Bergen, Norway.
Neuropsychologia. 2003;41(6):666-75. doi: 10.1016/s0028-3932(02)00224-5.
In the present study, we investigated differences between dyslexic and normal reading children in asymmetry of the planum temporale area in the upper posterior part of the temporal lobe and dichotic listening performance to consonant-vowel syllables. The current study was an extension of previous studies in our laboratory on the same participants, now including also girls and left-handers. There were 20 boys and 3 girls in the dyslexic group and 19 boys and 4 girls in the normal reading group. The age of the participants was 10-12 years for both groups. The participants were screened from a population of 950 students in the fourth school grade in the greater Bergen district. The planum temporale area was measured in sagittal magnetic resonance (MR) images. Mean left and right area and asymmetry index were compared between the groups. Dichotic presentations of consonant-vowel syllables made it possible to separately probe left and right hemisphere phonological function, and to correlate this with planum temporale area. The results showed a significantly larger left than right planum temporale area for both groups. However, while the right planum temporale area was similar for the dyslexic and control groups, the left planum temporale was significantly (one-tailed t-test) smaller in the dyslexic group. Both groups also showed a significant right ear advantage to the consonant-vowel syllables in the dichotic listening test. The relation between planum temporale and dichotic listening asymmetry showed a significant correlation for the dyslexic group only, indicating a positive relation between brain structure and function in dyslexic children. The results are discussed in terms of important subject characteristics with regard to brain markers of dyslexia.
在本研究中，我们调查了诵读困难儿童与正常阅读儿童在颞叶上部颞平面区域不对称性以及对辅音 - 元音音节的双耳分听表现方面的差异。本研究是我们实验室之前对相同参与者研究的扩展，现在研究对象还包括女孩和左撇子。诵读困难组有20名男孩和3名女孩，正常阅读组有19名男孩和4名女孩。两组参与者的年龄均为10 - 12岁。参与者是从卑尔根大区四年级的950名学生中筛选出来的。通过矢状面磁共振（MR）图像测量颞平面区域。比较了两组之间的左右平均面积和不对称指数。辅音 - 元音音节的双耳呈现使得能够分别探究左右半球的语音功能，并将其与颞平面区域相关联。结果显示，两组的左侧颞平面区域均显著大于右侧。然而，虽然诵读困难组和对照组的右侧颞平面区域相似，但诵读困难组的左侧颞平面区域明显更小（单尾t检验）。在双耳分听测试中，两组对辅音 - 元音音节也均表现出显著的右耳优势。仅诵读困难组的颞平面与双耳分听不对称之间的关系显示出显著相关性，这表明诵读困难儿童的脑结构与功能之间存在正相关。我们从诵读困难脑标志物的重要受试者特征方面对结果进行了讨论。
