Objective: To demonstrate the utility of rheoencephalography (REG) for measuring cerebral blood flow and fluid dynamics during different stages of sleep. Methods: Anteroposterior cranial electrical impedance was measured with concurrent polysomnography in a group of healthy subjects during sleep. Transcranial electrical impedance was characterized by measuring the peak-to-trough and envelope of the filtered pulsative REG signal as well as its frequency. The sensitivity of the REG amplitude to changes in cerebral blood flow (CBF) was confirmed by the analysis of the signal during breathing maneuvers with known effects on CBF. The mean amplitude and variability of the REG characteristic parameters were averaged across all participants and were compared between different stages of sleep. Results: Average transcranial impedance was significantly lower during non-REM stages N1 and N2, compared to other sleep stages, suggesting a decrease in CBF volume. Stage N3 showed the slowest frequency indicating a slow heart rate during this stage. N3 also had the lowest variability in frequency and peak-to-trough amplitude. Conclusion: Measurement of transcranial electrical conductivity may be a viable non-invasive method for monitoring any potential changes in intracranial fluid homeostasis. Clinical Impact: In the absence of other convenient non-invasive methods, using REG to track intracranial fluid dynamics during sleep can facilitate an improved understanding of pathogenesis in Alzheimer’s disease.

中文翻译：

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睡眠期间的经颅阻抗变化：Rheoencephalography 研究

目的：证明脑电图 (REG) 在测量不同睡眠阶段的脑血流量和流体动力学方面的效用。方法：在一组健康受试者睡眠期间，使用同步多导睡眠图测量前后颅电阻抗。经颅电阻抗通过测量滤波后的脉动 REG 信号的峰谷值和包络及其频率来表征。REG 振幅对脑血流 (CBF) 变化的敏感性通过对呼吸动作期间的信号分析得到证实，已知对 CBF 的影响。REG 特征参数的平均振幅和变异性在所有参与者中取平均值，并在不同睡眠阶段之间进行比较。结果：与其他睡眠阶段相比，非快速眼动阶段 N1 和 N2 的平均经颅阻抗显着降低，表明 CBF 量减少。N3 阶段显示最慢的频率，表明该阶段的心率较慢。N3 在频率和峰谷振幅方面的变异性也最低。结论：经颅电导率的测量可能是一种可行的非侵入性方法，用于监测颅内液稳态的任何潜在变化。临床影响：在没有其他方便的非侵入性方法的情况下，使用 REG 跟踪睡眠期间的颅内流体动力学可以促进对阿尔茨海默病发病机制的更好理解。N3 阶段显示最慢的频率，表明该阶段的心率较慢。N3 在频率和峰谷振幅方面的变异性也最低。结论：经颅电导率的测量可能是一种可行的非侵入性方法，用于监测颅内液稳态的任何潜在变化。临床影响：在没有其他方便的非侵入性方法的情况下，使用 REG 跟踪睡眠期间的颅内流体动力学可以促进对阿尔茨海默病发病机制的更好理解。N3 阶段显示最慢的频率，表明该阶段的心率较慢。N3 在频率和峰谷振幅方面的变异性也最低。结论：经颅电导率的测量可能是一种可行的非侵入性方法，用于监测颅内液稳态的任何潜在变化。临床影响：在没有其他方便的非侵入性方法的情况下，使用 REG 跟踪睡眠期间的颅内流体动力学可以促进对阿尔茨海默病发病机制的更好理解。