Shi Xiaoyan, Zhu Hongtu, Ibrahim Joseph G, Liang Faming, Lieberman Jeffrey, Styner Martin
H. Zhu is Professor of Biostatistics (
J Am Stat Assoc. 2012 Mar 1;107(497):12-23. doi: 10.1080/01621459.2011.643710.
The aim of this paper is to develop a semiparametric model for describing the variability of the medial representation of subcortical structures, which belongs to a Riemannian manifold, and establishing its association with covariates of interest, such as diagnostic status, age and gender. We develop a two-stage estimation procedure to calculate the parameter estimates. The first stage is to calculate an intrinsic least squares estimator of the parameter vector using the annealing evolutionary stochastic approximation Monte Carlo algorithm and then the second stage is to construct a set of estimating equations to obtain a more efficient estimate with the intrinsic least squares estimate as the starting point. We use Wald statistics to test linear hypotheses of unknown parameters and establish their limiting distributions. Simulation studies are used to evaluate the accuracy of our parameter estimates and the finite sample performance of the Wald statistics. We apply our methods to the detection of the difference in the morphological changes of the left and right hippocampi between schizophrenia patients and healthy controls using medial shape description.
本文的目的是开发一种半参数模型，用于描述属于黎曼流形的皮质下结构内侧表示的变异性，并建立其与感兴趣的协变量（如诊断状态、年龄和性别）之间的关联。我们开发了一种两阶段估计程序来计算参数估计值。第一阶段是使用退火进化随机近似蒙特卡罗算法计算参数向量的内在最小二乘估计量，然后第二阶段是以内在最小二乘估计量为起点构建一组估计方程，以获得更有效的估计值。我们使用 Wald 统计量来检验未知参数的线性假设并确定其极限分布。通过模拟研究来评估我们参数估计值的准确性以及 Wald 统计量的有限样本性能。我们将我们的方法应用于使用内侧形状描述来检测精神分裂症患者与健康对照之间左右海马形态变化的差异。
