Awareness and the EEG power spectrum: analysis of frequencies
Awareness and the EEG power spectrum: analysis of frequencies
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DOI：
10.1093/bja/aeh270
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发表时间：
2004-12-01
影响因子：
9.8
通讯作者：
Kochs, EF
中科院分区：
文献类型：
--
作者：
Dressler, O;Schneider, G;Kochs, EF
背景功率谱分析是脑电信号分析的一种行之有效的方法。光谱参数可用于量化麻醉剂对大脑的药理作用和镇静水平。这种方法，在许多变化，已被应用于麻醉监测的深度，并已被纳入几个市售的EEG监测器。由于EEG频谱分析的重要性，我们评估了功率谱中每个频率在意识检测方面的性能。从包含围手术期记录的EEG数据的数据库中获得90个长度为8 s的无伪影EEG片段。在本分析中，EEG数据选自39例丙泊酚-瑞芬太尼或七氟烷-瑞芬太尼麻醉的患者，有一段时间的意识。一半的EEG片段记录在意识期间，定义为对命令“紧握我的手”的充分反应。另一半来自无反应的患者。计算每段的功率谱密度。作为感知检测器的功率谱的每个频点的性能用重新映射的预测概率rP（K）（即映射到0.5- 1的范围的预测概率P-K）来评估。低频（26 Hz）的重映射预测概率较高（rP（K）>0.8），最小值（rP（K）35 Hz）> 0.95。意识检测的最佳性能通过EEG功率谱频率从>35 Hz到127 Hz实现。该频带可以由肌肉活动支配。如较低的rP（K）值所反映的，15和26 Hz之间的频带可能具有有限的值。
Background. Power spectral analysis is a well-established method for the analysis of EEG signals. Spectral parameters can be used to quantify pharmacological effects of anaesthetics on the brain and the level of sedation. This method, in numerous variations, has been applied to depth of anaesthesia monitoring and has been incorporated into several commercially available EEG monitors. Because of the importance of EEG spectral analysis, we evaluated the performance of each frequency in the power spectrum regarding detection of awareness.Methods. Ninety artefact-free EEG segments of length 8 s were obtained from a database that contains perioperatively recorded EEG data. For the present analysis, EEG data were selected from 39 patients with propofol-remifentanil or sevoflurane-remifentanil anaesthesia with a period of awareness. Half of the EEG segments were recorded during periods of awareness as defined by an adequate response to the command 'squeeze my hand'. The other half were from unresponsive patients. The power spectral density was calculated for each segment. The performance of each frequency bin of the power spectrum as a detector of awareness was assessed with a remapped prediction probability rP(K), i.e. the prediction probability P-K mapped to a range of 0.5-1.Results. The remapped prediction probability was high (rP(K)>0.8) for low frequencies (26 Hz), with a minimum (rP(K)35 Hz) was >0.95.Conclusions. The best performance for the detection of awareness was achieved by EEG power spectral frequencies from >35 Hz up to 127 Hz. This frequency band may be dominated by muscle activity. The frequency band between 15 and 26 Hz may be of limited value, as reflected by lower rP(K) values.