Frontal Alpha EEG Asymmetry Variation of Depression Patients Assessed by Entropy Measures and Lemple–Ziv Complexity

• Published in: Journal of medical and biological engineering Vol. 41; no. 2; pp. 146 - 154
• Main Authors: Zhao, Lulu, Yang, Licai, Li, Baimin, Su, Zhonghua, Liu, Chengyu
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2021; Springer Nature B.V
• Subjects: Asymmetry; Biomarkers; Biomedical Engineering and Bioengineering; Cell Biology; Complexity; EEG; Electroencephalography; Engineering; Entropy; Imaging; Mental depression; Original Article; Radiology; Sample entropy; Depression; Lemple–Ziv complexity; Cross-sample entropy; Frontal asymmetry
• ISSN: 1609-0985; 2199-4757
• DOI: 10.1007/s40846-020-00594-9

Purpose As depression has been a major contributor to the global disease burden, objective and effective computer-aided diagnosis has become an urgent problem. This study aims to assess the frontal asymmetry variation of alpha electroencephalography (EEG) in different severity depression patients and to find promising biomarkers for future depression recognition. Methods Three-channel EEG signals from 69 depression patients (divided into three groups according to illness severity) and 14 healthy subjects were collected. Except for cross-sample entropy (CSEn), two new asymmetry indexes (Asy_SEn and Asy_LZC) based on complexity measures were proposed to quantify the difference among the four groups. One-way ANOVA was used to test the difference among all four groups, followed by the group t -test to test the difference between each two groups. Results All indexes show significantly increased frontal alpha asymmetry in depressive groups compared with the healthy group, and the asymmetry keeps increasing as the depression deepens. The Asy_LZC value of the confirmed depression group (0.0015 ± 0.0008) is substantially higher than the other three groups (−0.0010 ± 0.0008, −0.0006 ± 0.0008, and −0.0007 ± 0.0006). And the Asy_SEn value of the healthy group (−0.0023 ± 0.0007) is significantly lower than the two depressive groups (0.0001 ± 0.0005 and 0.0007 ± 0.0007). All healthy CSEn between each two channels is considerably lower than depressive groups with p  < 0.01. Conclusion This study confirms the increased frontal alpha asymmetry in depression patients and suggests that two new indexes could be promising biomarkers in future clinical depression detection.