Analysis of EEG Mu Rhythms in Stroke and Leukoaraiosis Patients Using Multivariate Empirical Mode Decomposition

• Main Authors: Fang-jhen Lin, 林芳禎
• Other Authors: Po-lei Lee
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/60151669507444688555

碩士 === 國立中央大學 === 電機工程學系 === 101 === This study aims to analyze movement-related sensorimotor Mu rhythm when leukoaraiosis patients and semi-paralyzed stroke patients were performing self-paced finger movement task. The investigation of differences between patients and normal subjects were also performed. Leukoaraiosis is a descriptive term used to describe neuroimaging findings of diffuse hemispheric white matter abnormalities mainly characterized by loss of myelin and/or ischemic injury. Leukoaraiosis is a major risk factor and prognostic factor for stroke. Similar to leukoaraiosis, we found the sensorimotor Mu rhythm in stroke patients are also affected in performing finger movement task. Since EEG signals are weak (μv) and stochastic, the use of traditional digital filter may be unable to well extract the stochastic sensorimotor rhythms which could result in the pitfall of underestimating subject’s responses. Accordingly, a novel tool, multivariate empirical mode decomposition (MEMD), was adopted in this study to exact the sensorimotor Mu rhythm in human brain. The MEMD decomposes multi-channel EEG into sets of multi-channel intrinsic mode functions (IMF). Each set contains IMFs with similar frequency range across different channels, and each IMF is analytic, band-limited, and self-organized. The superiority of MEMD enables its capability in extracting stochastic signals. This study recruited ten stroke patients and ten leukoaraiosis patients. The stroke patients were asked to continuously perform the self-paced index finger tapping tasks, and the leukoaraiosis patients were asked to perform the movement once seven seconds. Our results demonstrated that the suppressed post-movement beta event-related desynchronizations (post-movement beta ERS) were found both in stroke and leukoaraiosis patients while performing finger movement tasks. It might be expected the measure of post-movement beta ERS could be a plausible index for evaluating patients’ motor function in future clinical applications.