Department of Biomedical Engineering, Technomedicum of the Tallinn University of Technology, 5 Ehitajate Road, 19086 Tallinn, Estonia.
Comput Math Methods Med. 2013;2013:251638. doi: 10.1155/2013/251638. Epub 2013 Oct 22.
This study was aimed to compare two electroencephalogram (EEG) analysis methods, spectral asymmetry index (SASI) and Higuchi's fractal dimension (HFD), for detection of depression. Linear SASI method is based on evaluation of the balance of powers in two EEG frequency bands in one channel selected higher and lower than the alpha band spectrum maximum. Nonlinear HFD method calculates fractal dimension directly in the time domain. The resting EEG signals of 17 depressive patients and 17 control subjects were used as a database for calculations. SASI values were positive for depressive and negative for control group (P < 0.05). SASI provided the true detection rate of 88% in the depressive and 82% in the control group. The calculated HFD values detected a small (3%) increase with depression (P < 0.05). HFD provided the true detection rate of 94% in the depressive group and 76% in the control group. The rate of correct indication in the both groups was 85% using SASI or HFD. Statistically significant variations were not revealed between hemispheres (P > 0.05). The results indicated that the linear EEG analysis method SASI and the nonlinear HFD method both demonstrated a good sensitivity for detection of characteristic features of depression in a single-channel EEG.
本研究旨在比较两种脑电图（EEG）分析方法，即频谱不对称指数（SASI）和 Higuchi 的分形维数（HFD），以检测抑郁症。线性 SASI 方法基于评估所选高于和低于 alpha 频段谱最大值的一个通道中两个 EEG 频段的功率平衡。非线性 HFD 方法直接在时域中计算分形维数。17 名抑郁患者和 17 名对照组的静息 EEG 信号被用作计算数据库。SASI 值对抑郁组为正，对对照组为负（P <0.05）。SASI 在抑郁组的真实检出率为 88%，在对照组的真实检出率为 82%。计算出的 HFD 值检测到抑郁时略有增加（3%）（P <0.05）。HFD 在抑郁组的真实检出率为 94%，在对照组的真实检出率为 76%。使用 SASI 或 HFD，两组的正确指示率均为 85%。半球之间未显示出统计学上的显著差异（P >0.05）。结果表明，线性 EEG 分析方法 SASI 和非线性 HFD 方法在单通道 EEG 中均能很好地检测出抑郁症的特征。
