Rae C, Lee M A, Dixon R M, Blamire A M, Thompson C H, Styles P, Talcott J, Richardson A J, Stein J F
MRC Biochemical and Clinical Magnetic Resonance Unit, John Radcliffe Hospital, Oxford, UK.
Lancet. 1998 Jun 20;351(9119):1849-52. doi: 10.1016/S0140-6736(97)99001-2.
Neurological and physiological deficits have been reported in the brain in developmental dyslexia. The temporoparietal cortex has been directly implicated in dyslexic dysfunction, and substantial indirect evidence suggests that the cerebellum is also implicated. We wanted to find out whether the neurological and physiological deficits manifested as biochemical changes in the brain.
We obtained localised proton magnetic resonance spectra bilaterally from the temporo-parietal cortex and cerebellum of 14 well-defined dyslexic men and 15 control men of similar age.
We found biochemical differences between dyslexic men and controls in the left temporo-parietal lobe (ratio of choline-containing compounds [Cho] to N-acetylaspartate [NA] p< or =0.01) and right cerebellum (Cho/NA, p< or = 0.01; creatine [Cre] to NA p< or =0.05; (not significant). We found lateral biochemical differences in dyslexic men in both these brain regions (Cho/NA in temporo-parietal lobe, left vs right, p< or =0.01; Cre/NA in cerebellum, left vs right, p< or =0.001). We found no such lateral differences in controls. There was no significant relation between the degree of contralateral chemical difference and handedness in dyslexic or control men.
We suggest that the observed differences reflect changes in cell density in the temporo-parietal lobe in developmental dyslexia and that the altered cerebral structural symmetry in dyslexia is associated with abnormal development of cells or intracellular connections or both. The cerebellum is biochemically asymmetric in dyslexic men, indicating altered development of this organ. These differences provide direct evidence of the involvement of the cerebellum in dyslexic dysfunction.
发育性阅读障碍患者大脑中存在神经和生理缺陷的报道。颞顶叶皮质直接与阅读障碍功能障碍有关，大量间接证据表明小脑也与之相关。我们想弄清楚神经和生理缺陷是否表现为大脑中的生化变化。
我们从14名明确诊断为阅读障碍的男性和15名年龄相仿的对照男性的双侧颞顶叶皮质和小脑中获取了局部质子磁共振波谱。
我们发现阅读障碍男性与对照者在左侧颞顶叶（含胆碱化合物[Cho]与N - 乙酰天门冬氨酸[NA]的比值，p≤0.01）和右侧小脑（Cho/NA，p≤0.01；肌酸[Cre]与NA的比值，p≤0.05）存在生化差异。我们还发现阅读障碍男性在这两个脑区均存在侧别生化差异（颞顶叶的Cho/NA，左侧与右侧相比，p≤0.01；小脑的Cre/NA，左侧与右侧相比，p≤0.001）。而对照者未发现此类侧别差异。阅读障碍或对照男性中，对侧化学差异程度与利手之间无显著关联。
我们认为观察到的差异反映了发育性阅读障碍患者颞顶叶细胞密度的变化，且阅读障碍中大脑结构对称性的改变与细胞或细胞内连接或两者的异常发育有关。阅读障碍男性的小脑存在生化不对称性，表明该器官发育异常。这些差异为小脑参与阅读障碍功能障碍提供了直接证据。
