Mary Mackillop Institute for Health Research, Australian Catholic University, Melbourne, Australia; Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia.
Institute for Radiological Research, Chang Gung University and Chang Gung Memorial Hospital, Taoyuan, Taiwan; Department of Child and Adolescent Psychiatry, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan.
Neuroimage Clin. 2021;30:102621. doi: 10.1016/j.nicl.2021.102621. Epub 2021 Mar 10.
Traumatic brain injury (TBI) is one of the leading causes of death and disability in children and adolescents. Young TBI patients suffer from gross motor deficits, such as postural control deficits, which can severely compromise their daily life activities. However, little attention has been devoted to uncovering the underlying white matter changes in response to training in TBI. In this study, we used longitudinal fixel-based analysis (FBA), an advanced diffusion imaging analysis technique, to investigate the effect of a balance training program on white matter fibre density and morphology in a group of young TBI patients.
Young patients with moderate-to-severe TBI (N = 17, 10 females, mean age = 13 ± 3 years) and age-matched controls (N = 17) underwent a home-based balance training program. Diffusion MRI scans together with gross motor assessments, including the gross motor items of the Bruininks-Oseretsky Test of Motor Proficiency, the Activities-Specific Balance Confidence (ABC) Scale, and the Sensory Organization Test (SOT) were administered before and at completion of 8-weeks of training. We used FBA to compare microstructural differences in fibre density (FD), macrostructural (morphological) changes in fibre cross-section (FC), and the combined FD and FC (FDC) metric across the whole brain. We then performed a longitudinal analysis to test whether training restores the white matter in the regions found to be damaged before treatment.
Whole-brain fixel-based analysis revealed lower FD and FC in TBI patients compared to the control group across several commissural tracts, association fibres and projection fibres, with FD reductions of up to 50%. Following training, TBI patients showed a significant interaction effect between Group and Time for the SOT test, as well as significant increases in macrostructural white matter (i.e., FC & FDC) in left sensorimotor tracts. The amount of change in FC and FDC over time was, however, not associated with behavioural changes.
Our fixel-based findings identified both microstructural and macrostructural abnormalities in young TBI patients. The longitudinal results provide a deeper understanding of the neurobiological mechanisms underlying balance training, which will allow clinicians to make more effective treatment decisions in everyday clinical practice with brain-injured patients.
创伤性脑损伤（TBI）是儿童和青少年死亡和残疾的主要原因之一。年轻的 TBI 患者存在严重的运动缺陷，例如姿势控制缺陷，这严重影响了他们的日常生活活动。然而，人们很少关注到 TBI 患者在训练后白质的潜在变化。在这项研究中，我们使用基于固定体素的分析（FBA），一种先进的扩散成像分析技术，来研究平衡训练计划对一组年轻 TBI 患者白质纤维密度和形态的影响。
患有中重度 TBI 的年轻患者（N=17，女性 10 名，平均年龄 13±3 岁）和年龄匹配的对照组（N=17）接受了一项家庭平衡训练计划。在训练前和 8 周训练结束时，对扩散 MRI 扫描以及运动能力评估，包括布鲁因克斯-奥塞尔斯基运动能力测试的粗大运动项目、活动特异性平衡信心量表（ABC 量表）和感觉组织测试（SOT）进行了评估。我们使用 FBA 比较全脑纤维密度（FD）、纤维横截面的宏观结构（形态）变化（FC）以及 FD 和 FC 联合（FDC）指标的微观结构差异。然后进行了纵向分析，以测试治疗前发现的白质损伤区域是否在治疗后得到恢复。
全脑固定体素分析显示，与对照组相比，TBI 患者在几个连合束、联合纤维和投射纤维中存在较低的 FD 和 FC，FD 减少高达 50%。经过训练，TBI 患者在 SOT 测试中表现出组间和时间的显著交互作用，以及左侧感觉运动束的宏观白质（即 FC 和 FDC）显著增加。然而，随着时间的推移，FC 和 FDC 的变化量与行为变化无关。
我们的固定体素研究发现，年轻的 TBI 患者存在微观和宏观结构异常。纵向结果更深入地了解了平衡训练的神经生物学机制，这将使临床医生在日常临床实践中为脑损伤患者做出更有效的治疗决策。
