Jagust William, Gitcho Amy, Sun Felice, Kuczynski Beth, Mungas Dan, Haan Mary
School of Public Health, University of California, Berkeley, USA.
Ann Neurol. 2006 Apr;59(4):673-81. doi: 10.1002/ana.20799.
This study was designed to test the hypothesis that baseline glucose metabolism and medial temporal lobe brain volumes are predictive of cognitive decline in normal older people.
We performed positron emission tomography using [18F]fluorodeoxyglucose and structural magnetic resonance imaging at baseline in 60 cognitively normal community-dwelling older subjects who were part of a longitudinal cohort study. Subjects were followed for a mean of 3.8 years, with approximately annual evaluation of global cognition (the Modified Mini-Mental State Examination) and episodic memory (delayed recall). Baseline brain volumes and glucose metabolism were evaluated in relation to the rate of change in cognitive test scores.
Six subjects developed incident dementia or cognitive impairment (converters). Baseline positron emission tomography scans showed regions in left and right angular gyrus, left mid-temporal gyrus, and left middle frontal gyrus that predicted the rate of change on the Modified Mini-Mental State Examination (p < 0.001). The left hemisphere temporal and parietal regions remained significant when converters were excluded. Both hippocampal (p = 0.03) and entorhinal cortical volumes (p = 0.01) predicted decline on delayed recall over time, and entorhinal cortical volumes remained significant when converters were excluded (p = 0.02). These brain volumes did not predict Modified Mini-Mental State Examination decline.
These results indicate that temporal and parietal glucose metabolism predict decline in global cognitive function, and medial temporal brain volumes predict memory decline in normal older people. The anatomical location of these findings suggests detection of preclinical Alzheimer's disease pathology.
本研究旨在验证以下假设，即基线葡萄糖代谢和内侧颞叶脑容量可预测正常老年人的认知衰退。
我们对60名认知正常、居住在社区的老年人进行了正电子发射断层扫描（使用[18F]氟脱氧葡萄糖）和基线结构磁共振成像，这些老年人是一项纵向队列研究的一部分。对受试者进行了平均3.8年的随访，大约每年评估一次整体认知（改良简易精神状态检查）和情景记忆（延迟回忆）。评估了基线脑容量和葡萄糖代谢与认知测试分数变化率之间的关系。
6名受试者出现了新发痴呆或认知障碍（转变者）。基线正电子发射断层扫描显示，左右角回、左侧颞中回和左侧额中回的区域可预测改良简易精神状态检查的变化率（p < 0.001）。排除转变者后，左半球颞叶和顶叶区域仍具有显著性。海马体（p = 0.03）和内嗅皮质体积（p = 0.01）均预测了延迟回忆随时间的衰退，排除转变者后，内嗅皮质体积仍具有显著性（p = 0.02）。这些脑容量并未预测改良简易精神状态检查的衰退。
这些结果表明，颞叶和顶叶的葡萄糖代谢可预测整体认知功能的衰退，内侧颞叶脑容量可预测正常老年人的记忆衰退。这些发现的解剖位置提示检测到了临床前阿尔茨海默病病理。
