Table_2_Diffusion Tensor Imaging (DTI) Correlates of Self-Reported Sleep Quality and Depression Following Mild Traumatic Brain Injury.DOCX

Background: Mild traumatic brain injuries (mTBIs) are a significant social, sport, and military health issue. In spite of advances in the clinical management of these injuries, the underlying pathophysiology is not well-understood. There is a critical need to advance objective biomarkers, allowing the identification and tracking of the long-term evolution of changes resulting from mTBI. Diffusion-weighted imaging (DWI) allows for the assessment of white-matter properties in the brain and shows promise as a suitable biomarker of mTBI pathophysiology.
Methods: 34 individuals within a year of an mTBI (age: 24.4 ± 7.4) and 18 individuals with no history of mTBI (age: 23.2 ± 3.4) participated in this study. Participants completed self-report measures related to functional outcomes, psychological health, post-injury symptoms, and sleep, and underwent a neuroimaging session that included DWI. Whole-brain white matter was skeletonized using tract-based spatial statistics (TBSS) and compared between groups as well as correlated within-group with the self-report measures.
Results: There were no statistically significant anatomical differences between the two groups. After controlling for time since injury, fractional anisotropy (FA) demonstrated a negative correlation with sleep quality scores (higher FA was associated with better sleep quality) and increasing depressive symptoms in the mTBI participants. Conversely, mean (MD) and radial diffusivity (RD) demonstrated positive correlations with sleep quality scores (higher RD was associated with worse sleep quality) and increasing depressive symptoms. These correlations were observed bilaterally in the internal capsule (anterior and posterior limbs), corona radiata (anterior and superior), fornix, and superior fronto-occipital fasciculi.
Conclusion: The results of this study indicate that the clinical presentation of mTBI, particularly with respect to depression and sleep, is associated with reduced white-matter integrity in multiple areas of the brain, even after controlling for time since injury. These areas are generally associated not only with sleep and emotion regulation but also cognition. Consequently, the onset of depression and sleep dysfunction as well as cognitive impairments following mTBI may be closely related to each other and to white-matter integrity throughout the brain.

背景：轻度创伤性脑损伤（mild traumatic brain injuries, mTBI）是一类严重影响社会、体育及军事领域的健康问题。尽管此类损伤的临床诊疗手段已取得进展，但其潜在的病理生理学机制仍未得到充分阐明。当前亟需开发客观生物标志物，以实现对轻度创伤性脑损伤所致脑改变的长期演化过程进行识别与追踪。弥散加权成像（diffusion-weighted imaging, DWI）可用于评估脑白质特性，其作为反映轻度创伤性脑损伤病理生理的潜在生物标志物展现出应用前景。
方法：本研究共招募34例发病一年内的轻度创伤性脑损伤患者（年龄：24.4 ± 7.4）以及18例无轻度创伤性脑损伤病史的健康对照者（年龄：23.2 ± 3.4）。所有受试者完成了涵盖功能结局、心理健康、伤后症状及睡眠状况的自评量表，并接受了包含弥散加权成像序列的神经影像学扫描。采用基于纤维束的空间统计（tract-based spatial statistics, TBSS）方法对全脑白质进行骨架化处理，随后进行组间比较，并在组内与自评量表结果进行相关性分析。
结果：两组受试者的解剖结构未观察到统计学意义上的显著差异。在校正伤后时长这一混杂因素后，轻度创伤性脑损伤患者的各向异性分数（fractional anisotropy, FA）与睡眠质量评分呈负相关（FA值越高，睡眠质量越好），且与抑郁症状加重呈正相关。与之相反，平均弥散率（mean diffusivity, MD）与径向弥散率（radial diffusivity, RD）与睡眠质量评分呈正相关（RD值越高，睡眠质量越差），且与抑郁症状加重呈正相关。上述相关性在双侧内囊（前肢、后肢）、放射冠（前部、上部）、穹窿以及额上枕束中均有体现。
结论：本研究结果表明，即便在校正伤后时长后，轻度创伤性脑损伤的临床表现——尤其是与抑郁及睡眠相关的症状——与脑内多个区域的白质完整性降低存在关联。这些脑区通常不仅与睡眠及情绪调节相关，同时也参与认知功能调控。因此，轻度创伤性脑损伤后出现的抑郁、睡眠功能障碍及认知损伤可能彼此紧密相关，且均与全脑白质完整性密切关联。