晚发性抑郁症脑白质改变的弥散张量成像研究

White matter microstructure abnormalities of Late-life depression: A diffusion tensor imaging study

关键词:  晚发性抑郁症  弥散张量成像  血管危险因素

Key words:  [Key words]　depressive disorder  diffusion magnetic resonance imaging  vascular risk factor

摘要:

[摘要]　目的　探讨晚发性抑郁症（late-onset depression，LOD）患者脑白质微结构的改变。　方法　对20名LOD患者及16名在性别、年龄、教育年限以及血管危险因素评分均相匹配的健康老年人（对照组）进行执行功能测验和磁共振弥散张量成像扫描，在选取的感兴趣区分别对各向异性分数（fractional anisotropy,FA）进行组间比较，并分析其与执行功能、病情严重程度之间的相关性。　结果　LOD患者执行功能较对照组明显下降，患者右前额叶背外侧白质区及右侧前扣带束FA值较对照组减低（Ps<0.05）；在病例组，左前扣带束FA值和Stroop测验C卡片耗时、耗时干扰效应量呈负相关（Ps<0.05）。 　结论　右前额叶背外侧白质区及右侧前扣带束白质微结构损害可能是LOD患者抑郁症状和执行功能障碍的生物学基础。

Abstract:

[Abstract] Objective　To investigate white matter microstructure abnormalities in late-onset depression (LOD).　Methods　Twenty late-onset depressed subjects and 16 elderly non-depressed subjects underwent clinical assessment and diffusion tensor imaging. We compared the results between groups while controlling for age, sex, education and Framingham Stroke Risk Profile scores. The fractional anisotropy (FA) were measured in sixteen regions of interest including dorsal lateral prefrontal lobe, anterior cingulum, posterior cingulum, corpus callosum, middle and basal regions of prefrontal lobe, and occipital lobe. Executive function was assessed with the Stroop task and Verbal fluency task. Correlation analysis was used to examine the relationship between FA and severity of depression and executive function.　Results　Performances in the Stroop test were significantly impaired in the LOD group as compared with the control group (P<0.05). A significant group-hemisphere interaction effect was found on FA value of the dorsal lateral prefrontal region (F1,34=5.369，P=0.027). The white matter of right dorsal lateral prefrontal lobe and right anterior cingulate bundle shown decreased FA compared to the controls (F1,34=8.113，P=0.007 and F1,34=13.980，P=0.001). In the LOD group，correlation analysis revealed negative correlation between FA value in right anterior cingulate bundle and index of Stroop test (P<0.05).　Conclusion　Regardless of vascular risk factors, white matter microstructure abnormalities in the right dorsal lateral prefrontal lobe and right anterior cingulate bundle maybe the biological basis of LOD.