Neurobehavioral Clinical Research Section, Social and Behavioral Research Branch, National Human Genome Research Institute, National Institute of Mental Health, NIH, Bethesda, MD, USA.
Cerebral Imaging Centre, Douglas Mental Health University Institute, Montreal, QC, Canada.
J Child Psychol Psychiatry. 2018 Oct;59(10):1114-1123. doi: 10.1111/jcpp.12920. Epub 2018 Apr 25.
The cerebellum supports many cognitive functions disrupted in attention deficit hyperactivity disorder (ADHD). Prior neuroanatomic studies have been often limited by small sample sizes, inconsistent findings, and a reliance on cross-sectional data, limiting inferences about cerebellar development. Here, we conduct a multicohort study using longitudinal data, to characterize cerebellar development.
Growth trajectories of the cerebellar vermis, hemispheres and white matter were estimated using piecewise linear regression from 1,656 youth; of whom 63% had longitudinal data, totaling 2,914 scans. Four cohorts participated, all contained childhood data (age 4-12 years); two had adolescent data (12-25 years). Growth parameters were combined using random-effects meta-analysis.
Diagnostic differences in growth were confined to the corpus medullare (cerebellar white matter). Here, the ADHD group showed slower growth in early childhood compared to the typically developing group (left corpus medullare z = 2.49, p = .01; right z = 2.03, p = .04). This reversed in late childhood, with faster growth in ADHD in the left corpus medullare (z = 2.06, p = .04). Findings held when gender, intelligence, comorbidity, and psychostimulant medication were considered.
Across four independent cohorts, containing predominately longitudinal data, we found diagnostic differences in the growth of cerebellar white matter. In ADHD, slower white matter growth in early childhood was followed by faster growth in late childhood. The findings are consistent with the concept of ADHD as a disorder of the brain's structural connections, formed partly by developing cortico-cerebellar white matter tracts.
小脑支持注意力缺陷多动障碍（ADHD）中受损的许多认知功能。先前的神经解剖研究通常受到样本量小、结果不一致以及对横断面数据的依赖的限制，限制了对小脑发育的推断。在这里，我们使用纵向数据进行多队列研究，以描述小脑的发育情况。
使用分段线性回归从 1656 名青少年中估计小脑蚓部、半球和白质的生长轨迹；其中 63%有纵向数据，总计 2914 次扫描。有四个队列参与，所有队列都包含儿童时期的数据（4-12 岁）；其中两个队列有青少年时期的数据（12-25 岁）。使用随机效应荟萃分析结合生长参数。
生长方面的诊断差异仅限于脑桥髓质（小脑白质）。在这里，与对照组相比，ADHD 组在儿童早期的生长速度较慢（左侧脑桥髓质 z=2.49，p=0.01；右侧 z=2.03，p=0.04）。这种情况在儿童后期发生了逆转，ADHD 组左侧脑桥髓质的生长速度更快（z=2.06，p=0.04）。当考虑性别、智力、合并症和精神兴奋剂药物时，结果仍然成立。
在四个独立的队列中，包含主要的纵向数据，我们发现小脑白质的生长存在诊断差异。在 ADHD 中，儿童早期较慢的白质生长随后是儿童后期较快的生长。这些发现与 ADHD 作为大脑结构连接障碍的概念一致，部分由发育中的皮质-小脑白质束形成。
