Saykin A J, Wishart H A, Rabin L A, Santulli R B, Flashman L A, West J D, McHugh T L, Mamourian A C
Brain Imaging Laboratory, Department of Psychiatry, Dartmouth Medical School, Hanover, NH, USA.
Neurology. 2006 Sep 12;67(5):834-42. doi: 10.1212/01.wnl.0000234032.77541.a2.
To examine the neural basis of cognitive complaints in healthy older adults in the absence of memory impairment and to determine whether there are medial temporal lobe (MTL) gray matter (GM) changes as reported in Alzheimer disease (AD) and amnestic mild cognitive impairment (MCI).
Participants were 40 euthymic individuals with cognitive complaints (CCs) who had normal neuropsychological test performance. The authors compared their structural brain MRI scans to those of 40 patients with amnestic MCI and 40 healthy controls (HCs) using voxel-based morphometry and hippocampal volume analysis.
The CC and MCI groups showed similar patterns of decreased GM relative to the HC group on whole brain analysis, with differences evident in the MTL, frontotemporal, and other neocortical regions. The degree of GM loss was associated with extent of both memory complaints and performance deficits. Manually segmented hippocampal volumes, adjusted for age and intracranial volume, were significantly reduced only in the MCI group, with the CC group showing an intermediate level.
Cognitive complaints in older adults may indicate underlying neurodegenerative changes even when unaccompanied by deficits on formal testing. The cognitive complaint group may represent a pre-mild cognitive impairment stage and may provide an earlier therapeutic opportunity than mild cognitive impairment. MRI analysis approaches incorporating signal intensity may have greater sensitivity in early preclinical stages than volumetric methods.
研究无记忆障碍的健康老年人认知主诉的神经基础，并确定是否存在如阿尔茨海默病（AD）和遗忘型轻度认知障碍（MCI）中所报道的内侧颞叶（MTL）灰质（GM）变化。
参与者为40名有认知主诉（CCs）且神经心理测试表现正常的心境正常个体。作者使用基于体素的形态测量法和海马体积分析，将他们的脑部结构MRI扫描结果与40名遗忘型MCI患者和40名健康对照（HCs）的结果进行比较。
在全脑分析中，CC组和MCI组相对于HC组均显示出类似的GM减少模式，在MTL、额颞叶和其他新皮质区域存在明显差异。GM损失程度与记忆主诉和表现缺陷的程度相关。经年龄和颅内体积校正后的手动分割海马体积仅在MCI组中显著减小，CC组显示出中间水平。
即使在正式测试中无缺陷，老年人的认知主诉也可能表明潜在的神经退行性变化。认知主诉组可能代表轻度认知障碍前期阶段，可能比轻度认知障碍提供更早的治疗机会。与体积测量方法相比，结合信号强度的MRI分析方法在临床前期早期可能具有更高的敏感性。
