Joubert Sven, Gour Natalina, Guedj Eric, Didic Mira, Guériot Claude, Koric Lejla, Ranjeva Jean-Philippe, Felician Olivier, Guye Maxime, Ceccaldi Mathieu
Département de psychologie, Université de Montréal, Montréal, Quebec, Canada; Centre de recherche Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, Quebec, Canada.
Université Aix-Marseille, INSERM, Institut des Neurosciences des Systèmes (INS) UMR 1106, Marseille, France; APHM, Hôpitaux de la Timone, Service de Neurologie et de Neuropsychologie, Marseille, France; Aix-Marseille Université, CNRS, CRMBM UMR 7339, Marseille, France.
Cortex. 2016 Jan;74:217-32. doi: 10.1016/j.cortex.2015.10.014. Epub 2015 Nov 17.
The goal of this study was to investigate the specific patterns of memory breakdown in patients suffering from early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease (LOAD). Twenty EOAD patients, twenty LOAD patients, twenty matched younger controls, and twenty matched older controls participated in this study. All participants underwent a detailed neuropsychological assessment, an MRI scan, an FDG-PET scan, and AD patients had biomarkers as supporting evidence of both amyloïdopathy and neuronal injury. Results of the neuropsychological assessment showed that both EOAD and LOAD groups were impaired in the domains of memory, executive functions, language, praxis, and visuoconstructional abilities, when compared to their respective control groups. EOAD and LOAD groups, however, showed distinct patterns of memory impairment. Even though both groups were similarly affected on measures of episodic, short term and working memory, in contrast semantic memory was significantly more impaired in LOAD than in EOAD patients. The EOAD group was not more affected than the LOAD group in any memory domain. EOAD patients, however, showed significantly poorer performance in other cognitive domains including executive functions and visuoconstructional abilities. A more detailed analysis of the pattern of semantic memory performance among patient groups revealed that the LOAD was more profoundly impaired, in tasks of both spontaneous recall and semantic recognition. Voxel-Based Morphometry (VBM) analyses showed that impaired semantic performance in patients was associated with reduced gray matter volume in the anterior temporal lobe (ATL) region, while PET-FDG analyses revealed that poorer semantic performance was associated with greater hypometabolism in the left temporoparietal region, both areas reflecting key regions of the semantic network. Results of this study indicate that EOAD and LOAD patients present with distinct patterns of memory impairment, and that a genuine semantic impairment may represent one of the clinical hallmarks of LOAD.
本研究的目的是调查早发性阿尔茨海默病（EOAD）和晚发性阿尔茨海默病（LOAD）患者记忆衰退的具体模式。20名EOAD患者、20名LOAD患者、20名匹配的年轻对照者和20名匹配的老年对照者参与了本研究。所有参与者都接受了详细的神经心理学评估、MRI扫描、FDG-PET扫描，且AD患者有生物标志物作为淀粉样病变和神经元损伤的支持证据。神经心理学评估结果显示，与各自的对照组相比，EOAD组和LOAD组在记忆、执行功能、语言、实践和视空间构建能力等方面均受损。然而，EOAD组和LOAD组表现出不同的记忆损害模式。尽管两组在情景记忆、短期记忆和工作记忆测量方面受到的影响相似，但相比之下，LOAD组的语义记忆受损程度明显高于EOAD患者。EOAD组在任何记忆领域都没有比LOAD组受到更严重的影响。然而，EOAD患者在包括执行功能和视空间构建能力在内的其他认知领域表现明显更差。对患者组语义记忆表现模式的更详细分析表明，在自发回忆和语义识别任务中，LOAD组受损更严重。基于体素的形态计量学（VBM）分析显示，患者语义表现受损与颞叶前部（ATL）区域灰质体积减少有关，而PET-FDG分析显示，较差的语义表现与左侧颞顶叶区域更高的低代谢有关，这两个区域都反映了语义网络的关键区域。本研究结果表明，EOAD和LOAD患者表现出不同的记忆损害模式，真正的语义损害可能是LOAD的临床特征之一。
