Mostofsky Stewart H, Burgess Melanie P, Gidley Larson Jennifer C
Kennedy Krieger Institute, 707 N. Broadway, Baltimore, MD 21205, USA.
Brain. 2007 Aug;130(Pt 8):2117-22. doi: 10.1093/brain/awm129. Epub 2007 Jun 15.
Careful consideration of motor impairments, such as those documented in autism, can afford valuable insights into the neurological basis of developmental disorders. Motor signs are highly quantifiable and reproducible and can serve as markers for deficits in parallel systems important for socialization and communication. Correlations of motor signs with anatomic MRI (aMRI) measures therefore offer an important means of investigating brain abnormalities contributing to autism. Prior aMRI studies have revealed increased cerebral volume in young children with autism, particularly in 'outer zone' radiate white matter; however functional correlates of these findings have not been reported. In this study, we examined whether radiate white matter within the primary motor cortex would predict impaired motor performance in children with autism. Subjects included children ages 8-12 years: 20 with autism, 36 typically developing (TD) controls and 20 clinical controls with attention-deficit/hyperactivity disorder (ADHD). Regional tissue volumes were measured using an automated tissue classification algorithm followed by a semi-automated parcellation method. Motor performance was assessed using the Physical and Neurologic Examination of Subtle Signs (PANESS), with higher scores indicating poorer performance. Independent linear regression analyses revealed that for TD controls there was a significant negative correlation between total PANESS score and primary motor cortex white matter volume in both the right and left hemispheres, such that increased white matter volume predicted improved motor skill. In contrast, children with autism showed a robust positive correlation between total PANESS score and left hemisphere primary motor and premotor white matter volumes, such that increased white matter volume predicted poorer motor skill. No significant correlations were found for ADHD. Multivariate regression analyses revealed that the correlation between PANESS score and left motor cortex white matter volume in children with autism significantly differed from those in both ADHD and TD children. The correlation in ADHD did not significantly differ from that in TD children. The findings for the first time demonstrate an association between increasing radiate white matter volume and functional impairment in children with autism, in this case basic motor skill impairment. The observed association, which appears specific to autism, may be representative of global patterns of brain abnormality that not only contribute to motor dysfunction in autism, but also deficits in socialization and communication that define the disorder.
仔细考虑运动障碍，比如那些在自闭症中记录的障碍，能够为发育障碍的神经学基础提供有价值的见解。运动体征具有高度可量化和可重复性，并且可以作为对社交和沟通重要的并行系统中缺陷的标志物。因此，运动体征与解剖磁共振成像（aMRI）测量值之间的相关性为研究导致自闭症的大脑异常提供了一种重要手段。先前的aMRI研究显示，自闭症幼儿的脑容量增加，尤其是在“外层区域”的放射状白质中；然而，这些发现的功能相关性尚未见报道。在本研究中，我们检查了初级运动皮层内的放射状白质是否能预测自闭症儿童的运动表现受损。研究对象包括8至12岁的儿童：20名自闭症儿童、36名发育正常（TD）的对照儿童和20名患有注意力缺陷多动障碍（ADHD）的临床对照儿童。使用自动组织分类算法，随后采用半自动分割方法测量区域组织体积。使用细微体征的体格和神经学检查（PANESS）评估运动表现，分数越高表明表现越差。独立线性回归分析显示，对于TD对照儿童，左右半球的总PANESS分数与初级运动皮层白质体积之间存在显著负相关，即白质体积增加预示着运动技能提高。相比之下，自闭症儿童的总PANESS分数与左半球初级运动和运动前区白质体积之间存在强烈正相关，即白质体积增加预示着运动技能较差。ADHD儿童未发现显著相关性。多变量回归分析显示，自闭症儿童的PANESS分数与左运动皮层白质体积之间的相关性与ADHD儿童和TD儿童的相关性显著不同。ADHD儿童的相关性与TD儿童的相关性无显著差异。这些发现首次证明了自闭症儿童放射状白质体积增加与功能损害之间的关联，在这种情况下是基本运动技能损害。观察到的这种关联似乎是自闭症特有的，可能代表了大脑异常的整体模式，这种模式不仅导致自闭症中的运动功能障碍，还导致定义该疾病的社交和沟通缺陷。
