Department of Radiology, University of Bonn, Bonn, Germany.
Neurology. 2012 Sep 25;79(13):1332-9. doi: 10.1212/WNL.0b013e31826c1a8d. Epub 2012 Aug 22.
To identify biological evidence for Alzheimer disease (AD) in individuals with subjective memory impairment (SMI) and unimpaired cognitive performance and to investigate the longitudinal cognitive course in these subjects.
[¹⁸F]fluoro-2-deoxyglucose PET (FDG-PET) and structural MRI were acquired in 31 subjects with SMI and 56 controls. Cognitive follow-up testing was performed (average follow-up time: 35 months). Differences in baseline brain imaging data and in memory decline were assessed between both groups. Associations of memory decline with brain imaging data were tested.
The SMI group showed hypometabolism in the right precuneus and hypermetabolism in the right medial temporal lobe. Gray matter volume was reduced in the right hippocampus in the SMI group. At follow-up, subjects with SMI showed a poorer performance than controls on measures of episodic memory. Longitudinal memory decline in the SMI group was associated with reduced glucose metabolism in the right precuneus at baseline.
The cross-sectional difference in 2 independent neuroimaging modalities indicates early AD pathology in SMI. The poorer memory performance at follow-up and the association of reduced longitudinal memory performance with hypometabolism in the precuneus at baseline support the concept of SMI as the earliest manifestation of AD.
在主观记忆障碍（SMI）且认知功能未受损的个体中寻找阿尔茨海默病（AD）的生物学证据，并研究这些受试者的纵向认知过程。
对 31 名 SMI 受试者和 56 名对照者进行 [¹⁸F]氟代-2-脱氧葡萄糖正电子发射断层扫描（FDG-PET）和结构磁共振成像（MRI）检查。对认知随访测试进行（平均随访时间：35 个月）。评估两组间基线脑影像学数据和记忆减退的差异。测试记忆减退与脑影像学数据的相关性。
SMI 组右侧楔前叶代谢降低，右侧内侧颞叶代谢增加。SMI 组右侧海马灰质体积减少。随访时，SMI 组在情节记忆测试中的表现比对照组差。SMI 组的纵向记忆减退与基线时右侧楔前叶葡萄糖代谢减少有关。
2 种独立的神经影像学方法的横断面差异表明 SMI 存在早期 AD 病理。随访时记忆表现较差，以及纵向记忆减退与基线时楔前叶代谢减少的相关性，支持 SMI 是 AD 的最早表现这一概念。
