Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh Pittsburgh, PA, USA.
Front Aging Neurosci. 2011 Sep 27;3:11. doi: 10.3389/fnagi.2011.00011. eCollection 2011.
Slowing information processing is common among community-dwelling elderly and it predicts greater mortality and disability risk. Slowing information processing is related to brain macro-structural abnormalities. Specifically, greater global atrophy and greater small vessel disease of the white matter (WM) have been associated with slower processing speed. However, community-dwelling elderly with such macro-structural abnormalities can maintain processing speed. The roles of brain micro-structure for slow processing in very old adults living in the community is uncertain, as epidemiological studies relating these brain markers to cognition and in the context of other health characteristics are sparse.
Information processing is cross-sectionally associated with WM micro-structure independent of overt macro-structural abnormalities and also independent of health related characteristics.
Imaging indices of micro-structure diffusion tensor imaging (DTI) and magnetization transfer imaging (MTI), macro-structure white matter hyperintensities (WMH), gray matter (GM) volume, digit symbol substitution test (DSST), and health characteristics were measured in 272 elderly (mean age 83 years old, 43% men, 40% black) living in the community.
The DTI- and MTI-indices of micro-structure from the normal appearing WM and not from the normal appearing GM were associated with DSST score independent of WMH and GM volumes. Associations were also independent of age, race, gender, mini-mental score, systolic blood pressure, and prevalent myocardial infarction.
DTI and MTI-indices of normal appearing WM are indicators of information processing speed in this cohort of very old adults living in the community. Since processing slowing is a potent index of mortality and disability, these indices may serve as biomarkers in prevention or treatment trials of disability.
信息处理速度缓慢在社区居住的老年人中很常见，且与更高的死亡率和残疾风险相关。信息处理速度缓慢与大脑宏观结构异常有关。具体而言，大脑整体萎缩和白质（WM）小血管疾病与处理速度较慢有关。然而，具有这种宏观结构异常的社区居住老年人可以维持处理速度。在社区居住的非常老的成年人中，大脑微观结构对处理速度较慢的作用尚不确定，因为将这些大脑标志物与认知相关联的流行病学研究以及在其他健康特征的背景下的研究很少。
信息处理与 WM 微观结构呈横断面相关，与明显的宏观结构异常无关，也与健康相关特征无关。
在 272 名（平均年龄 83 岁，43%为男性，40%为黑人）社区居住的老年人中测量了微观结构扩散张量成像（DTI）和磁化传递成像（MTI）、宏观结构白质高信号（WMH）、灰质（GM）体积、数字符号替换测试（DSST）和健康特征。
正常表现 WM 的 DTI 和 MTI 微观结构指数与 DSST 评分相关，与 WMH 和 GM 体积无关。这些关联也独立于年龄、种族、性别、迷你精神状态评分、收缩压和既往心肌梗死。
正常表现 WM 的 DTI 和 MTI 微观结构指数是本社区居住的非常老的成年人信息处理速度的指标。由于处理速度缓慢是死亡率和残疾的有力指标，这些指数可能作为残疾预防或治疗试验的生物标志物。
