Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.
Department of Clinical and Experimental Medicine, University of Pisa, Italy.
Autism Res. 2016 Mar;9(3):382-92. doi: 10.1002/aur.1533. Epub 2015 Aug 17.
Recent diffusion tensor imaging studies in adolescents and children with Autism Spectrum Disorder (ASD) have reported a loss or an inversion of the typical left-right lateralization in fronto-temporal regions crucial for sociocommunicative skills. No studies explored atypical lateralization in toddlers and its correlation with clinical severity of ASD. We recruited a cohort of 20 subjects aged 36 months or younger receiving a first clinical diagnosis of ASD (15 males; age range 20-36 months). Patients underwent diffusion MRI (High-Angular-Resolution Diffusion Imaging protocol). Data from cortical parcellation were combined with tractography to obtain a connection matrix and diffusion indexes (DI ) including mean fractional anisotropy (DFA ), number of tracts (DNUM ), and total tract length (DTTL ). A laterality index was generated for each measure, and then correlated with the Autism Diagnostic Observation Schedule-Generic (ADOS-G) total score. Laterality indexes of DFA were significantly correlated with ADOS-G total scores only in two intrafrontal connected areas (correlation was positive in one case and negative in the other). Laterality indexes of DTTL and DNUM showed significant negative correlations (P < 0.05) in six connected areas, mainly fronto-temporal. This study provides first evidence of a significant correlation between brain lateralization of diffusion indexes and clinical severity in toddlers with a first diagnosis of ASD. Significant correlations mainly involved regions within the fronto-temporal circuits, known to be crucial for sociocommunicative skills. It is of interest that all correlations but one were negative, suggesting an inversion of the typical left-right asymmetry in subjects with most severe clinical impairment.
最近的一项针对自闭症谱系障碍（ASD）青少年和儿童的弥散张量成像研究报告称，在与社交沟通技能相关的额颞叶区域，存在典型的左右侧化丧失或反转。目前尚无研究探讨幼儿的非典型侧化及其与 ASD 临床严重程度的相关性。我们招募了一组 20 名年龄在 36 个月或以下的 ASD 首次临床诊断患者（15 名男性；年龄范围 20-36 个月）。患者接受了弥散 MRI（高角度分辨率弥散成像方案）检查。皮质分区数据与束追踪相结合，以获得连接矩阵和弥散指数（DI），包括平均各向异性分数（DFA）、束数（DNUM）和总束长（DTTL）。为每个指标生成一个侧化指数，然后将其与自闭症诊断观察量表-通用（ADOS-G）总分进行相关性分析。仅在两个额内连接区域，FA 的侧化指数与 ADOS-G 总分呈显著正相关（在一个区域为正相关，在另一个区域为负相关）。在六个连接区域，主要是额颞叶区域，DTTL 和 DNUM 的侧化指数呈显著负相关（P < 0.05）。这项研究首次提供了证据表明，在首次诊断为 ASD 的幼儿中，弥散指数的大脑侧化与临床严重程度之间存在显著相关性。显著相关性主要涉及到额颞叶回路内的区域，这些区域被认为对社交沟通技能至关重要。有趣的是，除了一个以外，所有的相关性都是负的，这表明在临床症状最严重的患者中，存在典型的左右侧化的反转。
