Melbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, Victoria 3053, Australia.
Centre for Mental Health, School of Health Sciences, Swinburne University of Technology, Victoria 3122, Australia.
Prog Neuropsychopharmacol Biol Psychiatry. 2024 Jan 10;128:110868. doi: 10.1016/j.pnpbp.2023.110868. Epub 2023 Oct 4.
Cognitive impairment is a prominent feature of bipolar disorder (BD), however the neural substrates underpinning it remain unclear. Several studies have explored white matter as a correlate of cognitive functioning in BD cohorts, but mixed results and varied methodologies from one to another make inferences about this relationship difficult to draw. Here we sought to systematically synthesise the findings of these studies to more clearly explicate the nature and extent of relationships between white matter and cognition in BD and determine best practice methodologies and areas for future research in this area. Using PRISMA guidelines, we identified and systematically reviewed 37 relevant studies, all of which were cross-sectional by design. There was substantial methodological heterogeneity and variability in the clinical presentations of BD cohorts encapsulated within the studies we reviewed, which complicated our synthesis of the findings. Nonetheless, there was some evidence that cognition is related to both white matter macrostructure and microstructure in people with BD. In particular, multiple microstructural studies consistently reported that higher fractional anisotropy, both globally and in the corpus callosum, associated with better complex attention skills and executive functioning. However, several reports did not identify any associations at all, and in general, associations between WM and cognition tended to only be evident in studies utilising larger samples and post-hoc selection of WM regions of interest. Further research with increased statistical power and standardised methods are required moving forward.
认知障碍是双相情感障碍（BD）的一个突出特征，但支撑它的神经基础仍不清楚。有几项研究探讨了脑白质作为 BD 队列认知功能的相关性，但由于一项研究到另一项研究的方法各不相同，结果也各不相同，因此很难对这种关系做出推断。在这里，我们试图系统地综合这些研究的结果，更清楚地阐明脑白质与 BD 认知之间的关系的性质和程度，并确定该领域未来研究的最佳实践方法和领域。我们使用 PRISMA 指南，确定并系统地回顾了 37 项相关研究，这些研究全部是横断面研究。我们回顾的研究中所包含的 BD 队列的临床表现存在很大的方法学异质性和可变性，这使我们对研究结果的综合变得复杂。尽管如此，仍有一些证据表明，认知与 BD 患者的脑白质宏观结构和微观结构都有关系。特别是，多项微观结构研究一致报告，整体和胼胝体的分数各向异性越高，与复杂注意力技能和执行功能越好相关。然而，有几个报告根本没有发现任何关联，而且一般来说，WM 与认知之间的关联往往只在使用更大样本和 WM 感兴趣区的事后选择的研究中才明显。未来需要进一步进行具有更大统计能力和标准化方法的研究。
