Melicher T, Horacek J, Hlinka J, Spaniel F, Tintera J, Ibrahim I, Mikolas P, Novak T, Mohr P, Hoschl C
Prague Psychiatric Center, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic; 3rd Faculty of Medicine, Charles University, Prague, Czech Republic.
Prague Psychiatric Center, Prague, Czech Republic; National Institute of Mental Health, Klecany, Czech Republic; 3rd Faculty of Medicine, Charles University, Prague, Czech Republic.
Schizophr Res. 2015 Mar;162(1-3):22-8. doi: 10.1016/j.schres.2015.01.029. Epub 2015 Feb 4.
White matter abnormality has been recently proposed as a pathophysiological feature of schizophrenia (SZ). However, most of the data available has been gathered from chronic patients, and was therefore possibly confounded by factors such as duration of the disease, and treatment received. The extent and localization of these changes is also not clear.
We examined a population of early stage SZ patients using diffusion tensor imaging (DTI). 77 SZ patients and 60 healthy controls (HCs) were included in the analysis using Tract-Based Spatial Statistics (TBSS). We have also analyzed 250 randomly created subsets of the original cohort, to investigate the relation between the result of TBSS analysis, and the size of the sample studied.
We have found a significant decrease in fractional anisotropy (FA) in the patient group. This change is present in most major white matter (WM) tracts including the corpus callosum, superior and inferior longitudinal fasciculi, inferior fronto-occipital fasciculus, and posterior thalamic radiation. Furthermore, we identified a clear trend towards an increase in the number and spatial extent of significant voxels reported, with an increasing number of subjects included in the analysis.
Our study shows that FA is significantly decreased in patients at an early stage of schizophrenia, and that the extent of this finding is dependent on the size of studied sample; therefore underpowered studies might produce results with false spatial localization.
白质异常最近被认为是精神分裂症（SZ）的一种病理生理特征。然而，现有的大多数数据是从慢性患者中收集的，因此可能受到疾病持续时间和接受治疗等因素的混淆。这些变化的程度和定位也不清楚。
我们使用扩散张量成像（DTI）检查了一组早期SZ患者。使用基于束的空间统计学（TBSS）对77例SZ患者和60名健康对照（HCs）进行分析。我们还分析了原始队列中250个随机创建的子集，以研究TBSS分析结果与所研究样本大小之间的关系。
我们发现患者组的分数各向异性（FA）显著降低。这种变化存在于大多数主要白质（WM）束中，包括胼胝体、上纵束和下纵束、额枕下束以及丘脑后辐射。此外，我们发现随着分析中纳入的受试者数量增加，报告的显著体素数量和空间范围有明显增加的趋势。
我们的研究表明，精神分裂症早期患者的FA显著降低，并且这一发现的程度取决于所研究样本的大小；因此，样本量不足的研究可能会产生空间定位错误的结果。
