Laboratory of Personality and Cognition, National Institute on Aging, 251 Bayview Blvd./BRC Room 4B335, Baltimore, MD 21224-6825, USA.
Neurology. 2010 Mar 9;74(10):807-15. doi: 10.1212/WNL.0b013e3181d3e3e9. Epub 2010 Feb 10.
To investigate whether longitudinal declines in cognition are associated with higher fibrillar amyloid-beta (Abeta) deposition in vivo in individuals without dementia.
[(11)C]PiB images were obtained to measure fibrillar Abeta burden in 57 participants without dementia from the Baltimore Longitudinal Study of Aging. Participants (33 men, 24 women) had a mean (SD) age of 78.7 (6.2) years. Six participants (4 men, 2 women) had mild cognitive impairment defined as Clinical Dementia Rating = 0.5. To measure [(11)C]PiB retention, distribution volume ratios (DVR) for 15 regions of interest were estimated by fitting a simplified reference tissue model to the measured time activity curves. Mixed effects regression was used to predict cognitive trajectories over time using data before and including time of PiB (mean follow-up 10.8 years), with mean cortical DVR, age at baseline, sex, and education as independent predictors. Voxel-based analysis identified local associations.
[(11)C]PiB retention was higher in older individuals. Greater declines over time in mental status and verbal learning and memory, but not visual memory, were associated significantly with higher PiB retention. Voxel-based analysis showed significant associations in frontal and lateral temporal regions.
Higher Abeta deposition is associated with greater longitudinal decline in mental status and verbal memory in the preceding years. The differential association for verbal but not visual memory may reflect the greater reliance of verbal word list learning on prefrontal regions, which show early Abeta deposition. Prospective imaging may help distinguish between individuals with evolving neuropathology who develop accelerated cognitive decline vs those with normal aging.
研究在无痴呆的个体中，认知能力的纵向下降是否与体内纤维状淀粉样蛋白-β（Abeta）沉积增加有关。
在无痴呆的巴尔的摩纵向研究老化参与者中，获得[(11)C]PiB 图像以测量纤维状 Abeta 负担。参与者（33 名男性，24 名女性）的平均（SD）年龄为 78.7（6.2）岁。6 名参与者（4 名男性，2 名女性）患有轻度认知障碍，定义为临床痴呆评定量表=0.5。为了测量[(11)C]PiB 保留，通过拟合简化参考组织模型来估计 15 个感兴趣区的分布体积比（DVR）到测量的时间活动曲线。使用混合效应回归，使用 PiB 之前和包括 PiB 时间的数据（平均随访 10.8 年）预测认知轨迹随时间的变化，将平均皮质 DVR、基线年龄、性别和教育作为独立预测因子。体素分析确定了局部关联。
[(11)C]PiB 保留在年龄较大的个体中较高。认知状态和语言学习记忆的时间下降幅度较大，而视觉记忆下降幅度较小，与 PiB 保留量较高显著相关。体素分析显示额叶和外侧颞叶区域存在显著关联。
较高的 Abeta 沉积与认知状态和语言记忆的纵向下降在之前的几年中有关。语言记忆但不是视觉记忆的差异关联可能反映了语言单词学习对前额叶区域的更大依赖，而前额叶区域显示出早期的 Abeta 沉积。前瞻性成像可能有助于区分出现进行性神经病理学变化并导致认知能力快速下降的个体与正常衰老的个体。
