Rosso Isabelle M, Olson Elizabeth A, Britton Jennifer C, Stewart S Evelyn, Papadimitriou George, Killgore William Ds, Makris Nikos, Wilhelm Sabine, Jenike Michael A, Rauch Scott L
Center for Depression, Anxiety and Stress Research, McLean Hospital, 115 Mill Street, mailstop 334, Belmont, MA 02478 USA ; Department of Psychiatry, Harvard Medical School, Boston, MA USA.
Department of Psychology, University of Miami, 5665 Ponce de Leon Blvd, Flipse Building, Coral Gables, Miami, FL 33146 USA.
Biol Mood Anxiety Disord. 2014 Dec 18;4(1):13. doi: 10.1186/s13587-014-0013-6. eCollection 2014.
Obsessive-compulsive disorder (OCD) is a common and debilitating neuropsychiatric illness thought to involve abnormal connectivity of widespread brain networks, including frontal-striatal-thalamic circuits. At least half of OCD cases arise in childhood and their underlying neuropathology may differ at least in part from that of adult-onset OCD. Yet, only a few studies have examined brain white matter (WM) integrity in childhood-onset OCD using diffusion tensor imaging (DTI), and none have examined potential associations with age at onset.
In this study, 17 youth with OCD and 19 healthy control subjects, ages 10 to 19 years, underwent DTI on a 3T Siemens scanner. DSM-IV diagnoses were established with standardized interviews, and OCD symptom severity was evaluated using the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS). Voxel-wise analyses were conducted on data processed with tract-based spatial statistics (TBSS) to derive measures of fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mean diffusivity (MD). OCD patients had significantly lower FA in seven WM clusters, with over 80% of significant voxels in bilateral frontal cortex and corpus callosum (CC). There were no regions of significantly higher FA in patients compared with controls. Patients also had significantly higher RD in right frontal cortex and right body of the CC. Earlier age at onset of OCD correlated significantly with lower FA in the right thalamus and with higher RD in the right CC. FA and RD were not significantly associated with symptom severity.
These findings point to compromised WM integrity and reduced myelination in some brain regions of children with OCD, particularly the CC and fiber tracts that connect the frontal lobes to widespread cortical and subcortical targets. They also suggest that age at onset may be a moderator of some of the WM changes in pediatric OCD.
强迫症（OCD）是一种常见且使人衰弱的神经精神疾病，被认为涉及广泛脑网络的异常连接，包括额叶 - 纹状体 - 丘脑回路。至少一半的强迫症病例在儿童期出现，其潜在的神经病理学可能至少部分不同于成人期发病的强迫症。然而，仅有少数研究使用扩散张量成像（DTI）检查儿童期发病的强迫症患者的脑白质（WM）完整性，且没有研究探讨其与发病年龄的潜在关联。
在本研究中，17名年龄在10至19岁的强迫症青少年和19名健康对照者在3T西门子扫描仪上接受了DTI检查。通过标准化访谈确立了《精神疾病诊断与统计手册》第四版（DSM-IV）诊断，并使用儿童耶鲁 - 布朗强迫症量表（CY-BOCS）评估强迫症症状严重程度。对基于纤维束的空间统计（TBSS）处理的数据进行体素级分析，以得出分数各向异性（FA）、轴向扩散率（AD）、径向扩散率（RD）和平均扩散率（MD）的测量值。强迫症患者在七个白质簇中的FA显著降低，超过80%的显著体素位于双侧额叶皮质和胼胝体（CC）。与对照组相比，患者没有FA显著更高的区域。患者右侧额叶皮质和右侧胼胝体体部的RD也显著更高。强迫症发病年龄越早，与右侧丘脑较低的FA以及右侧胼胝体较高的RD显著相关。FA和RD与症状严重程度无显著关联。
这些发现表明，强迫症儿童的某些脑区存在白质完整性受损和髓鞘形成减少的情况，尤其是胼胝体以及连接额叶与广泛皮质和皮质下靶点的纤维束。它们还表明，发病年龄可能是儿童强迫症中一些白质变化的调节因素。
