Author(s)

Mina Taheri, Behzad Ahmadi, Rassoul Amirfattahi, Mojtaba Mansouri

Digital Signal Processing Research Lab, Department of Electrical and Computer Engineering, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. Correspondence should be addressed to Mina Taheri.

A new approach to estimating level of uncon-sciousness based on Principal Component Analysis (PCA) is proposed. The Electroen-cephalogram (EEG) data was captured in both Intensive Care Unit (ICU) and operating room, using different anesthetic drugs. Assuming the central nervous system as a 20-tuple source, window length of 20 seconds is applied to EEG. The mentioned window is considered as 20 nonoverlapping mixed-signals (epoch). PCA algorithm is applied to these epochs, and larg-est remaining eigenvalue (LRE) and smallest remaining eigenvalue (SRE) were extracted. Correlation between extracted parameters (LRE and SRE) and depth of anesthesia (DOA) was measured using Prediction probability (PK). The results show the superiority of SRE than LRE in predicting DOA in the case of ICU and isoflurane, and the slight superiority of LRE than SRE in propofol induction. Finally, a mixture model containing both LRE and SRE could predict DOA as well as Relative Beta Ratio (RBR), which expresses the high capability of the proposed PCA based method in estimating DOA.

Bispectral Index, Depth of Anesthesia, Eignevalue Decomposition, Principal Component Analysis

Taheri, M. , Ahmadi, B. , Amirfattahi, R. and Mansouri, M. (2009) Assessment of depth of anesthesia using principal component analysis. Journal of Biomedical Science and Engineering, 2, 9-15. doi: 10.4236/jbise.2009.21002.