Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA.
Autism Res. 2010 Dec;3(6):350-8. doi: 10.1002/aur.162. Epub 2010 Dec 2.
Biological measurements that distinguish individuals with autism from typically developing individuals and those with other developmental and neuropsychiatric disorders must demonstrate very high performance to have clinical value as potential imaging biomarkers. We hypothesized that further study of white matter microstructure (WMM) in the superior temporal gyrus (STG) and temporal stem (TS), two brain regions in the temporal lobe containing circuitry central to language, emotion, and social cognition, would identify a useful combination of classification features and further understand autism neuropathology.
WMM measurements from the STG and TS were examined from 30 high-functioning males satisfying full criteria for idiopathic autism aged 7-28 years and 30 matched controls and a replication sample of 12 males with idiopathic autism and 7 matched controls who participated in a previous case-control diffusion tensor imaging (DTI) study. Language functioning, adaptive functioning, and psychotropic medication usage were also examined.
In the STG, we find reversed hemispheric asymmetry of two separable measures of directional diffusion coherence, tensor skewness, and fractional anisotropy. In autism, tensor skewness is greater on the right and fractional anisotropy is decreased on the left. We also find increased diffusion parallel to white matter fibers bilaterally. In the right not left TS, we find increased omnidirectional, parallel, and perpendicular diffusion. These six multivariate measurements possess very high ability to discriminate individuals with autism from individuals without autism with 94% sensitivity, 90% specificity, and 92% accuracy in our original and replication samples. We also report a near-significant association between the classifier and a quantitative trait index of autism and significant correlations between two classifier components and measures of language, IQ, and adaptive functioning in autism.
将个体自闭症与正常发育个体以及其他发育和神经精神障碍个体区分开来的生物学测量必须具有非常高的性能，才能作为潜在的成像生物标志物具有临床价值。我们假设进一步研究颞叶中包含语言、情感和社会认知核心回路的两个脑区——颞上回（STG）和颞干（TS）的白质微观结构（WMM），将确定一组有用的分类特征，并进一步了解自闭症的神经病理学。
从满足特发性自闭症全部标准的 30 名 7-28 岁高功能男性和 30 名匹配的对照组中检查 STG 和 TS 的 WMM 测量值，并对先前参加过特发性自闭症和 7 名匹配对照组的扩散张量成像（DTI）研究的 12 名男性进行了复制样本检查。还检查了语言功能、适应功能和精神药物使用情况。
在 STG 中，我们发现两个可分离的方向扩散相干性测量指标——张量偏度和各向异性分数的反向半球不对称性。在自闭症中，张量偏度在右侧较大，各向异性分数在左侧减小。我们还发现双侧的扩散平行于白质纤维增加。在右侧而不是左侧的 TS 中，我们发现各向同性、平行和垂直的扩散增加。这六个多元测量值具有非常高的能力，可以将自闭症个体与非自闭症个体区分开来，在我们的原始和复制样本中，敏感性为 94%，特异性为 90%，准确性为 92%。我们还报告了分类器与自闭症定量特征指数之间的接近显著关联，以及分类器两个组成部分与自闭症中语言、智商和适应功能测量值之间的显著相关性。
