Abstract：
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.
摘要：
认知障碍是双相情感障碍（BD）的一个突出特征，然而，支撑它的神经底物仍不清楚。几项研究已经探索了白质作为BD队列中认知功能的相关性，但是混合的结果和从一个到另一个不同的方法使得对这种关系的推论很难得出。在这里，我们试图系统地综合这些研究的结果，以更清楚地阐明BD中白质与认知之间关系的性质和程度，并确定该领域未来研究的最佳实践方法和领域。使用PRISMA指南，我们确定并系统地回顾了37项相关研究，所有这些都是按设计横截面的。在我们回顾的研究中，BD队列的临床表现存在实质性的方法学异质性和变异性。这让我们对研究结果的综合变得复杂。尽管如此，有证据表明，认知与BD患者的白质宏观结构和微观结构有关。特别是,多个微观结构研究一致报道较高的分数各向异性，无论是在全球范围内还是在胼胝体中，与更好的复杂注意力技能和执行功能相关。然而,几份报告根本没有发现任何关联，总的来说,WM与认知之间的关联往往仅在利用较大样本和事后选择感兴趣的WM区域的研究中明显。需要进一步研究增加统计能力和标准化方法。
