Interdepartmental Neuroscience Program, Yale University, USA.
Interdepartmental Neuroscience Program, Yale University, USA; Department of Radiology and Biomedical Imaging, Yale School of Medicine, USA; Department of Statistics and Data Science, Yale University, USA; Child Study Center, Yale School of Medicine, USA.
Neuroimage. 2019 Dec;203:116157. doi: 10.1016/j.neuroimage.2019.116157. Epub 2019 Sep 5.
Once considered mere noise, fMRI-based functional connectivity has become a major neuroscience tool in part due to early studies demonstrating its reliability. These fundamental studies revealed only the tip of the iceberg; over the past decade, many test-retest reliability studies have continued to add nuance to our understanding of this complex topic. A summary of these diverse and at times contradictory perspectives is needed.
We aimed to summarize the existing knowledge regarding test-retest reliability of functional connectivity at the most basic unit of analysis: the individual edge level. This entailed (1) a meta-analytic estimate of reliability and (2) a review of factors influencing reliability.
A search of Scopus was conducted to identify studies that estimated edge-level test-retest reliability. To facilitate comparisons across studies, eligibility was restricted to studies measuring reliability via the intraclass correlation coefficient (ICC). The meta-analysis included a random effects pooled estimate of mean edge-level ICC, with studies nested within datasets. The review included a narrative summary of factors influencing edge-level ICC.
From an initial pool of 212 studies, 44 studies were identified for the qualitative review and 25 studies for quantitative meta-analysis. On average, individual edges exhibited a "poor" ICC of 0.29 (95% CI = 0.23 to 0.36). The most reliable measurements tended to involve: (1) stronger, within-network, cortical edges, (2) eyes open, awake, and active recordings, (3) more within-subject data, (4) shorter test-retest intervals, (5) no artifact correction (likely due in part to reliable artifact), and (6) full correlation-based connectivity with shrinkage.
This study represents the first meta-analysis and systematic review investigating test-retest reliability of edge-level functional connectivity. Key findings suggest there is room for improvement, but care should be taken to avoid promoting reliability at the expense of validity. By pooling existing knowledge regarding this key facet of accuracy, this study supports broader efforts to improve inferences in the field.
基于功能磁共振成像的功能连接曾经被认为只是噪声，但由于早期的研究证明了其可靠性，它已成为神经科学的主要工具之一。这些基础研究只是揭示了冰山一角；在过去的十年中，许多测试-重测可靠性研究继续为我们理解这个复杂的主题增添细节。我们需要对这些多样化且有时相互矛盾的观点进行总结。
我们旨在总结功能连接在最基本的分析单元——个体边水平上的测试-重测可靠性的现有知识。这包括（1）对可靠性的元分析估计，以及（2）对影响可靠性因素的综述。
对 Scopus 进行了检索，以确定通过组内相关系数 (ICC) 来衡量可靠性的研究。为了便于比较，研究仅限于通过 ICC 来衡量可靠性的研究。元分析包括个体边水平 ICC 的随机效应汇总估计，研究嵌套在数据集内。综述包括对影响个体边 ICC 的因素的叙述性总结。
从最初的 212 项研究中，确定了 44 项研究用于定性综述，25 项研究用于定量元分析。平均而言，个体边表现出“较差”的 ICC 为 0.29（95%置信区间为 0.23 至 0.36）。最可靠的测量往往涉及：（1）更强的、网络内的皮质边缘，（2）睁眼、清醒和活跃记录，（3）更多的个体内数据，（4）更短的测试-重测间隔，（5）没有进行伪影校正（可能部分原因是可靠的伪影），以及（6）使用收缩的全相关连接。
这项研究是第一个对个体边水平功能连接的测试-重测可靠性进行元分析和系统综述的研究。主要发现表明，还有改进的空间，但在提高可靠性的同时应注意避免损害有效性。通过汇集关于这一准确性关键方面的现有知识，这项研究支持了更广泛地努力提高该领域的推论。
