Bejanin Alexandre, Desgranges Béatrice, La Joie Renaud, Landeau Brigitte, Perrotin Audrey, Mézenge Florence, Belliard Serge, de La Sayette Vincent, Eustache Francis, Chételat Gaël
U1077, Inserm, Caen, France.
UMR-S1077, Université de Caen - Normandie, Caen, France.
Hum Brain Mapp. 2017 Apr;38(4):1791-1800. doi: 10.1002/hbm.23482. Epub 2016 Dec 16.
This study aims at further understanding the distinct vulnerability of brain networks in Alzheimer's disease (AD) versus semantic dementia (SD) investigating the white matter injury associated with medial temporal lobe (MTL) atrophy in both conditions. Twenty-six AD patients, twenty-one SD patients, and thirty-nine controls underwent a high-resolution T1-MRI scan allowing to obtain maps of grey matter volume and white matter density. A statistical conjunction approach was used to identify MTL regions showing grey matter atrophy in both patient groups. The relationship between this common grey matter atrophy and white matter density maps was then assessed within each patient group. Patterns of grey matter atrophy were distinct in AD and SD but included a common region in the MTL, encompassing the hippocampus and amygdala. This common atrophy was associated with alterations in different white matter areas in AD versus SD, mainly including the cingulum and corpus callosum in AD, while restricted to the temporal lobe - essentially the uncinate and inferior longitudinal fasciculi - in SD. Complementary analyses revealed that these relationships remained significant when controlling for global atrophy or disease severity. Overall, this study provides the first evidence that atrophy of the same MTL region is related to damage in distinct white matter fibers in AD and SD. These different patterns emphasize the vulnerability of distinct brain networks related to the MTL in these two disorders, which might underlie the discrepancy in their symptoms. These results further suggest differences between AD and SD in the neuropathological processes occurring in the MTL. Hum Brain Mapp 38:1791-1800, 2017. © 2017 Wiley Periodicals, Inc.
本研究旨在通过调查阿尔茨海默病（AD）和语义性痴呆（SD）中与内侧颞叶（MTL）萎缩相关的白质损伤，进一步了解这两种疾病中脑网络的不同易损性。26例AD患者、21例SD患者和39名对照者接受了高分辨率T1-MRI扫描，以获取灰质体积和白质密度图。采用统计联合分析方法来识别在两组患者中均显示灰质萎缩的MTL区域。然后在每个患者组中评估这种共同的灰质萎缩与白质密度图之间的关系。AD和SD中的灰质萎缩模式不同，但在MTL中有一个共同区域，包括海马体和杏仁核。这种共同的萎缩与AD和SD中不同白质区域的改变有关，在AD中主要包括扣带和胼胝体，而在SD中则局限于颞叶——主要是钩束和下纵束。补充分析表明，在控制整体萎缩或疾病严重程度时，这些关系仍然显著。总体而言，本研究首次提供了证据，表明同一MTL区域的萎缩与AD和SD中不同白质纤维的损伤有关。这些不同的模式强调了这两种疾病中与MTL相关的不同脑网络的易损性，这可能是它们症状差异的基础。这些结果进一步表明AD和SD在MTL中发生的神经病理过程存在差异。《人类大脑图谱》38:1791 - 1800，2017年。© 2017威利期刊公司。
