Multiple sclerosis: neuroimaging provides insights into cognitive dysfunction in MS.
Multiple sclerosis: neuroimaging provides insights into cognitive dysfunction in MS.
复制标题
DOI：
10.1038/nrneurol.2015.15
复制
发表时间：
2015-03-01
期刊：
影响因子：
--
通讯作者：
Malkki, Hemi
中科院分区：
文献类型：
--
作者：
Malkki, Hemi
认知功能的逐渐丧失在多发性硬化症(MS)患者中很常见，但传统的MRI疾病进展指标提供的关于认知障碍的信息有限。现在，两项新的研究表明，亚临床疾病活动以及丘脑结构和功能的变化可以很好地预测认知能力。来自荷兰弗吉尼亚大学医学中心的曼诺·舒恩海姆和他的同事们将他们的研究重点放在丘脑--这是一个以其对感觉处理的重要性而闻名的大脑区域--来寻找与认知功能相关的核磁共振。“丘脑的萎缩是核磁共振测量中与多发性硬化症认知功能障碍最密切和最密切相关的，”舒恩海姆解释道。除了结构措施外，研究人员还研究了157名多发性硬化症患者和47名健康对照的丘脑和皮质区域之间的功能连接。研究人员发现，在所有MS患者中，丘脑体积缩小，平均弥散率增加--特别是在那些严重认知障碍的患者。有趣的是，在患有严重认知障碍的患者中，发现丘脑和多个皮质区域之间的功能连接性增加了。“我们将我们的发现解释为功能连接性的非适应性增加，”舒恩海姆评论道。“在认知功能正常的患者中，丘脑体积已经缩小，但只有严重认知障碍的患者表现出功能连接性的增强。”在另一项研究中，巴西坎皮纳斯大学的Alfredo Damasceno和他的同事评估了无症状Gd增强病变的数量--一种衡量多发性硬化症亚临床疾病活动的指标--作为认知功能障碍的潜在预测指标。大马士革诺说：“Gd增强病变可能与皮质和白质病变负担增加有关，这也会影响认知，所以我们决定调查亚临床疾病活动是否独立地导致认知能力下降。”研究人员用3T磁共振扫描了42名复发-缓解期多发性硬化症患者和30名健康对照。所有参与者还接受了认知测试。15%的患者在MRI上表现为亚临床疾病活动，这些患者的认知表现最差。皮质损伤负荷和Gd增强损伤是认知障碍的主要预测因素。这些研究突显了多发性硬化症认知缺陷的复杂性。“总的来说，这些发现证实了使用更先进的成像方法进行纵向认知研究的迫切需要，”Schoonheim总结道。
Gradual loss of cognitive function is common in patients with multiple sclerosis (MS), but traditional MRI measures of disease progression yield limited information about cognitive impairment. Now, two new studies suggest that subclinical disease activity, and changes in thalamic structure and function are good predictors of cognitive performance. Menno Schoonheim and colleagues from the VU University Medical Center, Netherlands, focused their search for MRI correlates of cognitive function on the thalamus—a brain area best known for its importance for sensory processing.“Atrophy of the thalamus is the MRI measurement that has been most strongly and robustly related to cognitive dysfunction in MS,” Schoonheim explains. Besides structural measures, the investigators also looked into functional connectivity between the thalamus and cortical areas in a cohort of 157 patients with MS and 47 healthy controls. The researchers discovered that thalamic volume was reduced and mean diffusivity was increased in all patients with MS—and particularly in those with severe cognitive impairment. Interestingly, functional connectivity between the thalamus and multiple cortical regions was found to be increased in the patients with severe cognitive impairment.“We interpreted our findings as a maladaptive increase in functional connectivity,” comments Schoonheim.“Thalamic volume was already reduced in cognitively preserved patients, but patients with severe cognitive impairment were the only group to show increased functional connectivity.” In another study, Alfredo Damasceno and co-workers from the University of Campinas, Brazil, evaluated the number of asymptomatic gadoliniumenhancing lesions—a measure of subclinical disease activity in MS—as potential predictor of cognitive dysfunction.“Gadolinium-enhancing lesions can be associated with increased burden of cortical and white matter lesions, which can also affect cognition, so we decided to investigate whether subclinical disease activity independently contributed to cognitive decline,” says Damasceno. The researchers scanned 42 patients with relapsing–remitting MS and 30 healthy controls with 3 T MRI. All participants also underwent cognitive testing. 15% of the patients showed subclinical disease activity on MRI, and these patients had the worst cognitive performance. Cortical lesion burden and gadolinium-enhancing lesions were the main predictors of cognitive deficits. These studies highlight the complexity that underlies cognitive deficits in MS.“Together, these findings corroborate the dire need for longitudinal cognitive studies using moreadvanced imaging measures,” concludes Schoonheim.