INTRODUCTIONThe limbic system is critical for memory function and degenerates early in the Alzheimer's disease continuum. Whether obstructive sleep apnea (OSA) is associated with alterations in the limbic white matter tracts remains understudied.METHODSPolysomnography, neurocognitive assessment, and brain magnetic resonance imaging (MRI) were performed in 126 individuals aged 55–86 years, including 70 cognitively unimpaired participants and 56 participants with mild cognitive impairment (MCI). OSA measures of interest were the apnea‐hypopnea index and composite variables of sleep fragmentation and hypoxemia. Microstructural properties of the cingulum, fornix, and uncinate fasciculus were estimated using free water‐corrected diffusion tensor imaging.RESULTSHigher levels of OSA‐related hypoxemia were associated with higher left fornix diffusivities only in participants with MCI. Microstructure of the other white matter tracts was not associated with OSA measures. Higher left fornix diffusivities correlated with poorer episodic verbal memory.DISCUSSIONOSA may contribute to fornix damage and memory dysfunction in MCI.Highlights Sleep apnea‐related hypoxemia was associated with altered fornix integrity in MCI. Altered fornix integrity correlated with poorer memory function. Sleep apnea may contribute to fornix damage and memory dysfunction in MCI.

中文翻译：

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穹窿完整性改变与轻度认知障碍中睡眠呼吸暂停相关的低氧血症有关

简介边缘系统对于记忆功能至关重要，并在阿尔茨海默病连续体的早期退化。阻塞性睡眠呼吸暂停 (OSA) 是否与边缘白质束的改变相关仍有待研究。 方法 对 126 名年龄 55-86 岁的个体进行多导睡眠图、神经认知评估和脑磁共振成像 (MRI)，其中包括 70 名认知未受损的参与者和56 名患有轻度认知障碍 (MCI) 的参与者。感兴趣的 OSA 测量指标是呼吸暂停低通气指数以及睡眠碎片和低氧血症的复合变量。使用自由水校正扩散张量成像评估扣带回、穹窿和钩束的微观结构特性。结果仅在 MCI 参与者中，较高水平的 OSA 相关低氧血症与较高的左穹窿扩散率相关。其他白质束的微观结构与 OSA 测量无关。左侧穹窿扩散度较高与情景言语记忆较差相关。讨论可能会导致 MCI 中的穹窿损伤和记忆功能障碍。 睡眠呼吸暂停相关的低氧血症与 MCI 中穹窿完整性的改变有关。 穹窿完整性改变与记忆功能较差相关。 睡眠呼吸暂停可能导致 MCI 的穹窿损伤和记忆功能障碍。