Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health, Section of Psychiatry, University of Genoa, Genoa, Italy.
Department of Radiology, Section of Neuroradiology, University of Genoa, Genoa, Italy.
J Affect Disord. 2016 Mar 15;193:39-50. doi: 10.1016/j.jad.2015.12.050. Epub 2015 Dec 30.
In recent years, diffusion tensor imaging (DTI) studies have detected subtle microstructural abnormalities of white matter (WM) in type I bipolar disorder (BD). However, WM alterations in the different phases of BD remain to be explored. The aims of this study is to investigate the WM alterations in the various phases of illness and their correlations with clinical and neurocognitive features.
We investigated the DTI-derived fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) in patients with type I BD (n=61) subdivided in manic (n=21), depressive (n=20) and euthymic phases (n=20) vs. healthy controls (n=42), using a tract-based spatial statistics (TBSS) approach. Then, we investigated whether the subgroups of patients in the various phases of illness present different patterns of WM abnormalities. Finally we studied the correlations between WM alterations and clinical-cognitive parameters.
We found a widespread alteration in WM microstructure (decrease in FA and increase in MD and RD) in BD when compared to controls. The various subgroups of BD showed different spatial patterns of WM alterations. A gradient of increasing WM abnormalities from the euthymic (low degree and localized WM alterations mainly in the midline structures) to the manic (more diffuse WM alterations affecting both midline and lateral structures) and, finally, to the depressive phase (high degree and widespread WM alterations), was found. Furthermore, the WM diffuse alterations correlated with cognitive deficits in BD, such as decreased fluency prompted by letter and decreased hits and increased omission errors at the continuous performance test.
Patients under treatment.
The WM alterations in type I BD showed different spatial patterns in the various phases of illness, mainly affecting the active phases, and correlated with some cognitive deficits. This suggests a complex trait- and state-dependent pathogenesis of WM abnormalities in BD.
近年来，弥散张量成像（DTI）研究发现 I 型双相障碍（BD）患者的白质（WM）存在细微的结构异常。然而，BD 不同发病阶段的 WM 改变仍有待探索。本研究旨在探讨疾病不同发病阶段的 WM 改变及其与临床和神经认知特征的相关性。
我们使用基于束的空间统计学（TBSS）方法，对 61 名 I 型 BD 患者（分为躁狂期 21 名、抑郁期 20 名和缓解期 20 名）和 42 名健康对照组进行了 DTI 衍生的分数各向异性（FA）、平均弥散度（MD）、径向弥散度（RD）和轴向弥散度（AD）的研究。然后，我们研究了不同发病阶段的患者亚组是否存在不同的 WM 异常模式。最后，我们研究了 WM 改变与临床认知参数之间的相关性。
与对照组相比，BD 患者的 WM 微观结构存在广泛改变（FA 降低，MD 和 RD 增加）。BD 的各个亚组显示出不同的 WM 改变空间模式。从缓解期（WM 异常程度低，主要局限于中线结构）到躁狂期（WM 异常更加弥散，影响中线和外侧结构），最后到抑郁期（WM 异常程度高，广泛存在），发现 WM 异常程度逐渐增加。此外，WM 弥漫性改变与 BD 的认知缺陷相关，如字母流畅性下降、连续表现测试的击中减少和遗漏错误增加。
患者正在接受治疗。
I 型 BD 的 WM 改变在疾病的不同发病阶段呈现出不同的空间模式，主要影响活跃阶段，与一些认知缺陷相关。这表明 WM 异常在 BD 中具有复杂的特质和状态依赖性发病机制。
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