Dept. of Physics, FFCLRP, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
Dept. of Neuroscience and Behavioral Sciences, FMRP, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
Mult Scler Relat Disord. 2018 Feb;20:136-143. doi: 10.1016/j.msard.2018.01.014. Epub 2018 Jan 31.
The Symbol Digit Modalities Test (SDMT) is widely used for cognitive evaluation of information processing speed (IPS), required in many cognitive operations. Despite being unspecific for different neurological disorders, it is sensitive to assess impaired performance related to stroke, Parkinson's disease, traumatic brain injury, and multiple sclerosis. However, in addition to evaluate the presence and severity of IPS impairment, it is of interest to determine the localization and integration of brain regions responsible for the functions assessed by the SDMT.
To review the studies that adapted the SDMT to the magnetic resonance environment and obtain the brain areas associated with the performance of the task in healthy subjects with a meta-analysis.
A systematic review was performed using ten studies published between 1990 and 2017, and selected from four databases. All studies included participants of both genders and age between 18 and 50 years, used Functional Magnetic Resonance Imaging (fMRI) and SDMT adaptation and reported brain regions associated with the task. Six of them also reported the region coordinates in a standard space, so they were included in a meta-analysis. Activation Likelihood Estimation algorithm, with significance for p < 0.05 corrected for multiple comparisons, was used to identify areas that are robustly related to the performance of the SDMT.
The areas predominantly reported in the studies of our meta-analysis were regions of the frontoparietal attentional network and occipital cortex, as well as cuneus, precuneus, and cerebellum. Individually all regions that survived the statistical threshold are consistent with what is expected after reviewing prospective studies.
The present study allowed the identification of brain areas activated during the performance of the SDMT in healthy subjects, and therefore it will help understanding the differences in brain activation by this task in clinical populations. Moreover, it may guide future studies of therapeutic strategies and interventions in those populations.
符号数字模态测试（SDMT）广泛用于评估信息处理速度（IPS），这是许多认知操作所必需的。尽管它对不同的神经障碍没有特异性，但它对评估与中风、帕金森病、创伤性脑损伤和多发性硬化症相关的受损表现很敏感。然而，除了评估 IPS 损伤的存在和严重程度外，确定负责 SDMT 评估的功能的大脑区域的定位和整合也很重要。
综述将 SDMT 适应磁共振环境的研究，并通过荟萃分析获得健康受试者完成任务时与大脑区域相关的结果。
系统检索了 1990 年至 2017 年期间发表的 10 项研究，这些研究来自四个数据库。所有研究均纳入了男女两性和 18-50 岁之间的参与者，使用功能磁共振成像（fMRI）和 SDMT 适应，并报告了与任务相关的大脑区域。其中 6 项研究还报告了标准空间中的区域坐标，因此它们被纳入荟萃分析。使用激活似然估计算法，对 p < 0.05 进行多重比较校正，以确定与 SDMT 表现密切相关的区域。
荟萃分析中报告的主要区域是额顶注意网络和枕叶皮层以及楔前叶、楔叶和小脑的区域。单独来看，所有通过统计学阈值的区域都与回顾前瞻性研究后的预期结果一致。
本研究有助于确定健康受试者在执行 SDMT 时激活的大脑区域，从而有助于理解在临床人群中该任务的大脑激活差异。此外，它还可以指导这些人群的治疗策略和干预措施的未来研究。
