The Application of Entropy in Motor Imagery Paradigms of Brain–Computer Interfaces

<b>Background:</b> In motor imagery brain–computer interface (MI-BCI) research, electroencephalogram (EEG) signals are complex and nonlinear. This complexity and nonlinearity render signal processing and classification challenging when employing traditional linear methods. Information en...

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Main Authors: Chengzhen Wu, Bo Yao, Xin Zhang, Ting Li, Jinhai Wang, Jiangbo Pu
Format: Article
Language:English
Published: MDPI AG 2025-02-01
Series:Brain Sciences
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Online Access:https://www.mdpi.com/2076-3425/15/2/168
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author Chengzhen Wu
Bo Yao
Xin Zhang
Ting Li
Jinhai Wang
Jiangbo Pu
author_facet Chengzhen Wu
Bo Yao
Xin Zhang
Ting Li
Jinhai Wang
Jiangbo Pu
author_sort Chengzhen Wu
collection DOAJ
description <b>Background:</b> In motor imagery brain–computer interface (MI-BCI) research, electroencephalogram (EEG) signals are complex and nonlinear. This complexity and nonlinearity render signal processing and classification challenging when employing traditional linear methods. Information entropy, with its intrinsic nonlinear characteristics, effectively captures the dynamic behavior of EEG signals, thereby addressing the limitations of traditional methods in capturing linear features. However, the multitude of entropy types leads to unclear application scenarios, with a lack of systematic descriptions. <b>Methods:</b> This study conducted a review of 63 high-quality research articles focused on the application of entropy in MI-BCI, published between 2019 and 2023. It summarizes the names, functions, and application scopes of 13 commonly used entropy measures. <b>Results:</b> The findings indicate that sample entropy (16.3%), Shannon entropy (13%), fuzzy entropy (12%), permutation entropy (9.8%), and approximate entropy (7.6%) are the most frequently utilized entropy features in MI-BCI. The majority of studies employ a single entropy feature (79.7%), with dual entropy (9.4%) and triple entropy (4.7%) being the most prevalent combinations in multiple entropy applications. The incorporation of entropy features can significantly enhance pattern classification accuracy (by 8–10%). Most studies (67%) utilize public datasets for classification verification, while a minority design and conduct experiments (28%), and only 5% combine both methods. <b>Conclusions:</b> Future research should delve into the effects of various entropy features on specific problems to clarify their application scenarios. As research methodologies continue to evolve and advance, entropy features are poised to play a significant role in a wide array of fields and contexts.
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spelling doaj-art-79a5df1cf7a64bc8971dc95d0ea98d142025-08-20T03:12:16ZengMDPI AGBrain Sciences2076-34252025-02-0115216810.3390/brainsci15020168The Application of Entropy in Motor Imagery Paradigms of Brain–Computer InterfacesChengzhen Wu0Bo Yao1Xin Zhang2Ting Li3Jinhai Wang4Jiangbo Pu5School of Life Sciences, Tiangong University, Tianjin 300387, ChinaInstitute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, ChinaInstitute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, ChinaInstitute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, ChinaSchool of Life Sciences, Tiangong University, Tianjin 300387, ChinaInstitute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300192, China<b>Background:</b> In motor imagery brain–computer interface (MI-BCI) research, electroencephalogram (EEG) signals are complex and nonlinear. This complexity and nonlinearity render signal processing and classification challenging when employing traditional linear methods. Information entropy, with its intrinsic nonlinear characteristics, effectively captures the dynamic behavior of EEG signals, thereby addressing the limitations of traditional methods in capturing linear features. However, the multitude of entropy types leads to unclear application scenarios, with a lack of systematic descriptions. <b>Methods:</b> This study conducted a review of 63 high-quality research articles focused on the application of entropy in MI-BCI, published between 2019 and 2023. It summarizes the names, functions, and application scopes of 13 commonly used entropy measures. <b>Results:</b> The findings indicate that sample entropy (16.3%), Shannon entropy (13%), fuzzy entropy (12%), permutation entropy (9.8%), and approximate entropy (7.6%) are the most frequently utilized entropy features in MI-BCI. The majority of studies employ a single entropy feature (79.7%), with dual entropy (9.4%) and triple entropy (4.7%) being the most prevalent combinations in multiple entropy applications. The incorporation of entropy features can significantly enhance pattern classification accuracy (by 8–10%). Most studies (67%) utilize public datasets for classification verification, while a minority design and conduct experiments (28%), and only 5% combine both methods. <b>Conclusions:</b> Future research should delve into the effects of various entropy features on specific problems to clarify their application scenarios. As research methodologies continue to evolve and advance, entropy features are poised to play a significant role in a wide array of fields and contexts.https://www.mdpi.com/2076-3425/15/2/168information entropymotor imageryelectroencephalogrampattern classification
spellingShingle Chengzhen Wu
Bo Yao
Xin Zhang
Ting Li
Jinhai Wang
Jiangbo Pu
The Application of Entropy in Motor Imagery Paradigms of Brain–Computer Interfaces
Brain Sciences
information entropy
motor imagery
electroencephalogram
pattern classification
title The Application of Entropy in Motor Imagery Paradigms of Brain–Computer Interfaces
title_full The Application of Entropy in Motor Imagery Paradigms of Brain–Computer Interfaces
title_fullStr The Application of Entropy in Motor Imagery Paradigms of Brain–Computer Interfaces
title_full_unstemmed The Application of Entropy in Motor Imagery Paradigms of Brain–Computer Interfaces
title_short The Application of Entropy in Motor Imagery Paradigms of Brain–Computer Interfaces
title_sort application of entropy in motor imagery paradigms of brain computer interfaces
topic information entropy
motor imagery
electroencephalogram
pattern classification
url https://www.mdpi.com/2076-3425/15/2/168
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