Comprehensive Medical Center of Sleep Disorders, Aoyama Hospital, Tokyo Women's Medical University (TWMU), 2-7-13 Kita-Aoyama, Minato-ku, Tokyo 107-0061, Japan.
NoruPro Light Systems Incorporation, 2-11-25 Tokura, Kokubunji-shi, Tokyo 185-0003, Japan.
Sleep Med. 2014 Jan;15(1):33-41. doi: 10.1016/j.sleep.2013.10.005. Epub 2013 Oct 30.
The pathophysiologic aspects of parasympathetic nerve (PN) function during sleep in patients with obstructive sleep apnea (OSA) studied by classical power spectrum analysis on heart rate variability (HRV) are highly controversial. The controversy is attributed to methodologic concerns, such as poor time resolution involved in power spectrum analysis. We aimed to establish the appropriate method for the investigation of PN function in OSA patients with apneas and hypopneas using instantaneous time-frequency analysis with complex demodulation (CD) and sufficient time resolution.
A total of 30 patients with PSG-confirmed mild to severe OSA were recruited for the analysis of frequency spectra contained in R-R intervals (RRI) of overnight electrocardiograph (ECG) tracings. High-frequency (HF) domains ranging between 0.15 and 0.40 Hz were selected for analysis. Among these domains, the HF domain with the maximum instantaneous amplitude was defined as the main HF peak and was used as the surrogate marker of PN discharge. Based on density spectrum array (DSA) map for main HF peak constructed with a time scale of 1s and a frequency resolution of 0.002 Hz (HF-DSA map), the shift in central frequency (CF) of main HF peak over time was continuously monitored. When the main HF peak with the same CF lasted for more than 20 s or 5 min on HF-DSA map, the PN function was considered to be stable or very stable. The measurements were then repeated after continuous positive airway pressure (CPAP) treatment.
The extent of PN-evoked modulation of RRI was enhanced in nonrapid eye movement (NREM) sleep, though the stability was reduced in both NREM and rapid eye movement (REM) sleep. These peculiar behaviors of PN function were reversed by CPAP treatment.
We found that instantaneous time-frequency analysis allowed estimation of transitional changes in PN function during sleep in OSA patients.
通过心率变异性（HRV）经典功率谱分析研究阻塞性睡眠呼吸暂停（OSA）患者睡眠时副交感神经（PN）功能的病理生理方面存在很大争议。这种争议归因于方法学上的担忧，例如功率谱分析中涉及的时间分辨率较差。我们旨在使用具有足够时间分辨率的复解调（CD）瞬时时频分析来建立一种合适的方法，以研究伴有呼吸暂停和低通气的 OSA 患者的 PN 功能。
共纳入 30 例经 PSG 证实的轻至重度 OSA 患者，对整夜心电图（ECG）记录的 R-R 间期（RRI）中包含的频域进行分析。选择 0.15 至 0.40 Hz 之间的高频（HF）域进行分析。在这些域中，具有最大瞬时幅度的 HF 域被定义为主要 HF 峰值，并用作 PN 放电的替代标志物。基于密度谱数组（DSA）图构建的 1 秒时间尺度和 0.002 Hz 频率分辨率（HF-DSA 图）的主要 HF 峰值的中心频率（CF）随时间的变化，连续监测主要 HF 峰值的 CF。当具有相同 CF 的主要 HF 峰值在 HF-DSA 图上持续超过 20 秒或 5 分钟时，认为 PN 功能稳定或非常稳定。然后在持续气道正压通气（CPAP）治疗后重复测量。
在非快速眼动（NREM）睡眠中，PN 对 RRI 的调制程度增强，尽管在 NREM 和快速眼动（REM）睡眠中稳定性降低。CPAP 治疗逆转了 PN 功能的这些特殊行为。
我们发现瞬时时频分析允许估计 OSA 患者睡眠期间 PN 功能的过渡变化。
