Ohisa Noriko, Ogawa Hiromasa, Murayama Nobuki, Yoshida Katsumi
Department of Clinical Laboratory, Tohoku University Hospital, Sendai 980-8574, Japan.
Rinsho Byori. 2010 Feb;58(2):119-23.
Polysomnography (PSG) is the gold standard for the diagnosis of sleep apnea hypopnea syndrome (SAHS), but it takes time to analyze the PSG and PSG cannot be performed repeatedly because of efforts and costs. Therefore, simplified sleep respiratory disorder indices in which are reflected the PSG results are needed. The Memcalc method, which is a combination of the maximum entropy method for spectral analysis and the non-linear least squares method for fitting analysis (Makin2, Suwa Trust, Tokyo, Japan) has recently been developed. Spectral entropy which is derived by the Memcalc method might be useful to expressing the trend of time-series behavior.
Spectral entropy of ECG which is calculated with the Memcalc method was evaluated by comparing to the PSG results.
Obstructive SAS patients (n = 79) and control volanteer (n = 7)
ECG was recorded using MemCalc-Makin2 (GMS) with PSG recording using Alice IV (Respironics) from 20:00 to 6:00. Spectral entropy of ECG, which was calculated every 2 seconds using the Memcalc method, was compared to sleep stages which were analyzed manually from PSG recordings.
Spectral entropy value (-0.473 vs. -0.418, p < 0.05) were significantly increased in the OSAHS compared to the control. For the entropy cutoff level of -0.423, sensitivity and specificity for OSAHS were 86.1% and 71.4%, respectively, resulting in a receiver operating characteristic with an area under the curve of 0.837. The absolute value of entropy had inverse correlation with stage 3.
Spectral entropy, which was calculated with Memcalc method, might be a possible index evaluating the quality of sleep.
多导睡眠图（PSG）是诊断睡眠呼吸暂停低通气综合征（SAHS）的金标准，但分析PSG耗时，且由于人力和成本因素无法重复进行。因此，需要能反映PSG结果的简化睡眠呼吸障碍指数。最近开发了一种Memcalc方法，它是光谱分析的最大熵方法与拟合分析的非线性最小二乘法的组合（Makin2，Suwa Trust，东京，日本）。通过Memcalc方法得出的光谱熵可能有助于表达时间序列行为的趋势。
通过与PSG结果比较，评估用Memcalc方法计算的心电图光谱熵。
阻塞性睡眠呼吸暂停综合征患者（n = 79）和对照志愿者（n = 7）
使用MemCalc - Makin2（GMS）记录心电图，同时使用Alice IV（Respironics）从20:00至6:00记录PSG。每2秒用Memcalc方法计算一次心电图的光谱熵，并与从PSG记录中人工分析的睡眠阶段进行比较。
与对照组相比，阻塞性睡眠呼吸暂停低通气综合征患者的光谱熵值（-0.473对-0.418，p < 0.05）显著增加。对于熵截止水平-0.423，阻塞性睡眠呼吸暂停低通气综合征的敏感性和特异性分别为86.1%和71.4%，曲线下面积为0.837的受试者工作特征曲线。熵的绝对值与3期呈负相关。
用Memcalc方法计算的光谱熵可能是评估睡眠质量的一个可能指标。
