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Lu Y, Yang W, Zhang X, Wu L, Li Y, Wang X, Huai Y. Unraveling the complexity of rapid eye movement microstates: insights from nonlinear EEG analysis. Sleep 2024; 47:zsae105. [PMID: 38695327 DOI: 10.1093/sleep/zsae105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/24/2024] [Indexed: 07/12/2024] Open
Abstract
Although rapid eye movement (REM) sleep is conventionally treated as a unified state, it comprises two distinct microstates: phasic and tonic REM. Recent research emphasizes the importance of understanding the interplay between these microstates, hypothesizing their role in transient shifts between sensory detachment and external awareness. Previous studies primarily employed linear metrics to probe cognitive states, such as oscillatory power, while in this study, we adopt Lempel-Ziv Complexity (LZC), to examine the nonlinear features of electroencephalographic (EEG) data from the REM microstates and to gain complementary insights into neural dynamics during REM sleep. Our findings demonstrate a noteworthy reduction in LZC during phasic REM compared to tonic REM states, signifying diminished EEG complexity in the former. Additionally, we noted a negative correlation between decreased LZC and delta band power, along with a positive correlation with alpha band power. This study highlights the potential of nonlinear EEG metrics, particularly LZC, in elucidating the distinct features of REM microstates. Overall, this research contributes to advancing our understanding of the complex dynamics within REM sleep and opens new avenues for exploring its implications in both clinical and nonclinical contexts.
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Affiliation(s)
- Yiqing Lu
- Department of Rehabilitation Medicine, Shenzhen Longhua District Central Hospital, Shenzhen, China
- Shenzhen Longhua District Rehabilitation Medical Equipment Development and Transformation Joint Key Laboratory, Shenzhen, China
| | - Weiwei Yang
- Department of Rehabilitation Medicine, Shenzhen Longhua District Central Hospital, Shenzhen, China
- Shenzhen Longhua District Rehabilitation Medical Equipment Development and Transformation Joint Key Laboratory, Shenzhen, China
| | - Xiaoyun Zhang
- Department of Rehabilitation Medicine, Shenzhen Longhua District Central Hospital, Shenzhen, China
- Shenzhen Longhua District Rehabilitation Medical Equipment Development and Transformation Joint Key Laboratory, Shenzhen, China
| | - Liang Wu
- Department of Rehabilitation Medicine, Shenzhen Longhua District Central Hospital, Shenzhen, China
- Shenzhen Longhua District Rehabilitation Medical Equipment Development and Transformation Joint Key Laboratory, Shenzhen, China
| | - Yongcheng Li
- CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Xin Wang
- Department of Rehabilitation Medicine, Clinical Medical College, Yangzhou University, Yangzhou, China
| | - Yaping Huai
- Department of Rehabilitation Medicine, Shenzhen Longhua District Central Hospital, Shenzhen, China
- Shenzhen Longhua District Rehabilitation Medical Equipment Development and Transformation Joint Key Laboratory, Shenzhen, China
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Ma D, Li C, Shi W, Fan Y, Liang H, Li L, Zhang Z, Yeh CH. Benefits From Different Modes of Slow and Deep Breathing on Vagal Modulation. IEEE JOURNAL OF TRANSLATIONAL ENGINEERING IN HEALTH AND MEDICINE 2024; 12:520-532. [PMID: 39050620 PMCID: PMC11268930 DOI: 10.1109/jtehm.2024.3419805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 05/18/2024] [Accepted: 06/24/2024] [Indexed: 07/27/2024]
Abstract
Slow and deep breathing (SDB) is a relaxation technique that can increase vagal activity. Respiratory sinus arrhythmia (RSA) serves as an index of vagal function usually quantified by the high-frequency power of heart rate variability (HRV). However, the low breathing rate during SDB results in deviations when estimating RSA by HRV. Besides, the impact of the inspiration-expiration (I: E) ratio and guidelines ways (fixed breathing rate or intelligent guidance) on SDB is not yet clear. In our study, 30 healthy people (mean age = 26.5 years, 17 females) participated in three SDB modes, including 6 breaths per minute (bpm) with an I:E ratio of 1:1/ 1:2, and intelligent guidance mode (I:E ratio of 1:2 with guiding to gradually lower breathing rate to 6 bpm). Parameters derived from HRV, multimodal coupling analysis (MMCA), Poincaré plot, and detrended fluctuation analysis were introduced to examine the effects of SDB exercises. Besides, multiple machine learning methods were applied to classify breathing patterns (spontaneous breathing vs. SDB) after feature selection by max-relevance and min-redundancy. All vagal-activity markers, especially MMCA-derived RSA, statistically increased during SDB. Among all SDB modes, breathing at 6 bpm with a 1:1 I:E ratio activated the vagal function the most statistically, while the intelligent guidance mode had more indicators that still significantly increased after training, including SDRR and MMCA-derived RSA, etc. About the classification of breathing patterns, the Naive Bayes classifier has the highest accuracy (92.2%) with input features including LFn, CPercent, pNN50, [Formula: see text], SDRatio, [Formula: see text], and LF. Our study proposed a system that can be applied to medical devices for automatic SDB identification and real-time feedback on the training effect. We demonstrated that breathing at 6 bpm with an I:E ratio of 1:1 performed best during the training phase, while intelligent guidance mode had a more long-lasting effect.
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Affiliation(s)
- Deshan Ma
- School of Information and ElectronicsBeijing Institute of TechnologyBeijing100811China
| | - Conghui Li
- Department of Child Rehabilitation MedicineThe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan450052China
| | - Wenbin Shi
- School of Information and ElectronicsBeijing Institute of TechnologyBeijing100811China
- Key Laboratory of Brain Health Intelligent Evaluation and InterventionMinistry of Education (Beijing Institute of Technology)Beijing100811China
| | - Yong Fan
- Centre for Artificial Intelligence in MedicineMedical Innovation Research DepartmentChinese PLA General HospitalBeijing100036China
| | - Hong Liang
- Centre for Artificial Intelligence in MedicineMedical Innovation Research DepartmentChinese PLA General HospitalBeijing100036China
| | - Lixuan Li
- Centre for Artificial Intelligence in MedicineMedical Innovation Research DepartmentChinese PLA General HospitalBeijing100036China
| | - Zhengbo Zhang
- Centre for Artificial Intelligence in MedicineMedical Innovation Research DepartmentChinese PLA General HospitalBeijing100036China
| | - Chien-Hung Yeh
- School of Information and ElectronicsBeijing Institute of TechnologyBeijing100811China
- Key Laboratory of Brain Health Intelligent Evaluation and InterventionMinistry of Education (Beijing Institute of Technology)Beijing100811China
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Bryant AG, Aquino K, Parkes L, Fornito A, Fulcher BD. Extracting interpretable signatures of whole-brain dynamics through systematic comparison. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.10.573372. [PMID: 38915560 PMCID: PMC11195072 DOI: 10.1101/2024.01.10.573372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
The brain's complex distributed dynamics are typically quantified using a limited set of manually selected statistical properties, leaving the possibility that alternative dynamical properties may outperform those reported for a given application. Here, we address this limitation by systematically comparing diverse, interpretable features of both intra-regional activity and inter-regional functional coupling from resting-state functional magnetic resonance imaging (rs-fMRI) data, demonstrating our method using case-control comparisons of four neuropsychiatric disorders. Our findings generally support the use of linear time-series analysis techniques for rs-fMRI case-control analyses, while also identifying new ways to quantify informative dynamical fMRI structures. While simple statistical representations of fMRI dynamics performed surprisingly well (e.g., properties within a single brain region), combining intra-regional properties with inter-regional coupling generally improved performance, underscoring the distributed, multifaceted changes to fMRI dynamics in neuropsychiatric disorders. The comprehensive, data-driven method introduced here enables systematic identification and interpretation of quantitative dynamical signatures of multivariate time-series data, with applicability beyond neuroimaging to diverse scientific problems involving complex time-varying systems.
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Affiliation(s)
- Annie G. Bryant
- School of Physics, The University of Sydney, Camperdown, NSW, Australia
| | - Kevin Aquino
- School of Physics, The University of Sydney, Camperdown, NSW, Australia
- Brain Key Incorporated, San Francisco, CA, USA
| | - Linden Parkes
- Department of Psychiatry, Brain Health Institute, Rutgers University, Piscataway, NJ, USA
- Turner Institute for Brain & Mental Health, Monash University, VIC, Australia
| | - Alex Fornito
- Turner Institute for Brain & Mental Health, Monash University, VIC, Australia
| | - Ben D. Fulcher
- School of Physics, The University of Sydney, Camperdown, NSW, Australia
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Kaya E, Saritas I. Identifying optimal channels and features for multi-participant motor imagery experiments across a participant's multi-day multi-class EEG data. Cogn Neurodyn 2024; 18:987-1003. [PMID: 38826644 PMCID: PMC11143128 DOI: 10.1007/s11571-023-09957-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 01/31/2023] [Accepted: 03/08/2023] [Indexed: 03/29/2023] Open
Abstract
The concept of the brain-computer interface (BCI) has become one of the popular research topics of recent times because it allows people to express their thoughts and control different applications and devices without actual movement. The communication between the brain and the computer or a machine is generally provided through Electroencephalogram (EEG) signals because they are cost-effective and easy to implement in normal life, not just in healthcare facilities. On the other hand, they are hard to process efficiently due to their nonlinearity and noisy nature. Thus, the field of BCI and EEG needs constant work and improvement. This paper focuses on generalizing the most efficient EEG channels and the most significant features of motor imagery (MI) signals by analyzing the recordings of one participant obtained over 20 different days. Because the classification performance usually decreases with an increasing number of class labels, we have realized the study by analyzing the signals through a new paradigm consisting of multi-class directional labels: right, left, forward, and backward. Afterward, the results are tested on EEG data obtained from 5 participants to see if the results are consistent with each other. The average accuracy of binary and multi-class classification using the Ensemble Subspace Discriminant classifier was found as 87.39 and 61.44%, respectively, with the most efficient 3-channel combination for daily BCI evaluation of one participant. On the other hand, the average accuracy of binary and multi-class classification was found as 71.84 and 50.42%, respectively, for 5 participants, with the most efficient channel combination of 4, where the first three are the same as the daily performance of one participant. During signal processing, the outliers of the signals were discarded by considering the channels separately. An algorithm was developed to dismiss the inconsistent samples within the classes. A novel adaptive filtering approach, correlation-based adaptive variational mode decomposition (CBAVMD), was proposed. The feature selection was realized based on the standard deviation values of the features between the classes. The paradigm based on the direction movements was found to be most effective, especially for binary classification of right and left directions. The generalization of effective channels and features was found to be generally successful.
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Affiliation(s)
- Esra Kaya
- Electrical and Electronics Engineering Department, Faculty of Technology, Selcuk University, Konya, Turkey
| | - Ismail Saritas
- Electrical and Electronics Engineering Department, Faculty of Technology, Selcuk University, Konya, Turkey
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Wang Y, Li S, Lu J, Feng K, Huang X, Hu F, Sun M, Zou Y, Li Y, Huang W, Zhou J. The complexity of glucose time series is associated with short- and long-term mortality in critically ill adults: a multi-center, prospective, observational study. J Endocrinol Invest 2024:10.1007/s40618-024-02393-4. [PMID: 38762634 DOI: 10.1007/s40618-024-02393-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 05/11/2024] [Indexed: 05/20/2024]
Abstract
BACKGROUND The wealth of data taken from continuous glucose monitoring (CGM) remains to be fully used. We aimed to evaluate the relationship between a promising new CGM metric, complexity of glucose time series index (CGI), and mortality in critically ill patients. METHODS A total of 293 patients admitted to mixed medical/surgical intensive care units from 5 medical centers in Shanghai were prospectively included between May 2020 and November 2021. CGI was assessed using intermittently scanned CGM, with a median monitoring period of 12.0 days. Outcome measures included short- and long-term mortality. RESULTS During a median follow-up period of 1.7 years, a total of 139 (47.4%) deaths were identified, of which 73 (24.9%) occurred within the first 30 days after ICU admission, and 103 (35.2%) within 90 days. The multivariable-adjusted HRs for 30-day mortality across ascending tertiles of CGI were 1.00 (reference), 0.68 (95% CI 0.38-1.22) and 0.36 (95% CI 0.19-0.70), respectively. For per 1-SD increase in CGI, the risk of 30-day mortality was decreased by 51% (HR 0.49, 95% CI 0.35-0.69). Further adjustment for HbA1c, mean glucose during hospitalization and glucose variability partially attenuated these associations, although the link between CGI and 30-day mortality remained significant (per 1-SD increase: HR 0.57, 95% CI 0.40-0.83). Similar results were observed when 90-day mortality was considered as the outcome. Furthermore, CGI was also significantly and independently associated with long-term mortality (per 1-SD increase: HR 0.77, 95% CI 0.61-0.97). CONCLUSIONS In critically ill patients, CGI is significantly associated with short- and long-term mortality.
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Affiliation(s)
- Y Wang
- Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine; Shanghai Clinical Center for Diabetes; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai, 200233, China
| | - S Li
- Department of Anesthesiology, Tongji University Affiliated Shanghai Tenth People's Hospital, Shanghai, China
- Department of Critical Care Medicine, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 600 Yishan Road, Shanghai, 200233, China
| | - J Lu
- Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine; Shanghai Clinical Center for Diabetes; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai, 200233, China
| | - K Feng
- Department of Critical Care Medicine, Jinshan Branch of Shanghai Sixth People's Hospital, Shanghai, China
| | - X Huang
- Department of Critical Care Medicine, Jinshan Branch of Shanghai Sixth People's Hospital, Shanghai, China
| | - F Hu
- Department of Critical Care Medicine, Shanghai Fengxian District Central Hospital, Shanghai, China
| | - M Sun
- Department of Critical Care Medicine, Shanghai Eighth People's Hospital, Shanghai, China
| | - Y Zou
- Department of Critical Care Medicine, Shanghai Sixth People's Hospital East Campus, Shanghai, China
| | - Y Li
- Department of Critical Care Medicine, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 600 Yishan Road, Shanghai, 200233, China.
- Department of Critical Care Medicine, Tongji University Affiliated Shanghai Tenth People's Hospital, 301 Yanan Middle Road, Shanghai, 200040, China.
| | - W Huang
- Department of Critical Care Medicine, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 600 Yishan Road, Shanghai, 200233, China.
- Department of Critical Care Medicine, Shanghai Xuhui Central Hospital, Zhongshan-Xuhui Hospital, Fudan University, 966 Huaihai Middle Road, Shanghai, 200031, China.
| | - J Zhou
- Department of Endocrinology and Metabolism, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine; Shanghai Clinical Center for Diabetes; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, 600 Yishan Road, Shanghai, 200233, China.
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Yao W. Permutation time irreversibility in sleep electroencephalograms: Dependence on sleep stage and the effect of equal values. Phys Rev E 2024; 109:054104. [PMID: 38907450 DOI: 10.1103/physreve.109.054104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 04/05/2024] [Indexed: 06/24/2024]
Abstract
Time irreversibility (TIR) refers to the manifestation of nonequilibrium brain activity influenced by various physiological conditions; however, the influence of sleep on electroencephalogram (EEG) TIR has not been sufficiently investigated. In this paper, a comprehensive study on permutation TIR (pTIR) of EEG data under different sleep stages is conducted. Two basic ordinal patterns (i.e., the original and amplitude permutations) are distinguished to simplify sleep EEGs, and then the influences of equal values and forbidden permutation on pTIR are elucidated. To detect pTIR of brain electric signals, five groups of EEGs in the awake, stages I, II, III, and rapid eye movement (REM) stages are collected from the public Polysomnographic Database in PhysioNet. Test results suggested that the pTIR of sleep EEGs significantly decreases as the sleep stage increases (p<0.001), with the awake and REM EEGs demonstrating greater differences than others. Comparative analysis and numerical simulations support the importance of equal values. Distribution of equal states, a simple quantification of amplitude fluctuations, significantly increases with the sleep stage (p<0.001). If these equalities are ignored, incorrect probabilistic differences may arise in the forward-backward and symmetric permutations of TIR, leading to contradictory results; moreover, the ascending and descending orders for symmetric permutations also lead different outcomes in sleep EEGs. Overall, pTIR in sleep EEGs contributes to our understanding of quantitative TIR and classification of sleep EEGs.
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Affiliation(s)
- Wenpo Yao
- State Key Laboratory of Organic Electronics and Information Displays, Institute of Advanced Materials, School of Chemistry and Life Sciences, School of Geographic and Biologic Information, Nanjing University of Posts and Telecommunications, Nanjing 210023, China and Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai 200433, China
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7
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Ai S, Ye S, Li G, Leng Y, Stone KL, Zhang M, Wing YK, Zhang J, Liang YY. Association of Disrupted Delta Wave Activity During Sleep With Long-Term Cardiovascular Disease and Mortality. J Am Coll Cardiol 2024; 83:1671-1684. [PMID: 38573282 DOI: 10.1016/j.jacc.2024.02.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/20/2024] [Accepted: 02/22/2024] [Indexed: 04/05/2024]
Abstract
BACKGROUND Delta wave activity is a prominent feature of deep sleep, which is significantly associated with sleep quality. OBJECTIVES The authors hypothesized that delta wave activity disruption during sleep could predict long-term cardiovascular disease (CVD) and CVD mortality risk. METHODS The authors used a comprehensive power spectral entropy-based method to assess delta wave activity during sleep based on overnight polysomnograms in 4,058 participants in the SHHS (Sleep Heart Health Study) and 2,193 participants in the MrOS (Osteoporotic Fractures in Men Study) Sleep study. RESULTS During 11.0 ± 2.8 years of follow-up in SHHS, 729 participants had incident CVD and 192 participants died due to CVD. During 15.5 ± 4.4 years of follow-up in MrOS, 547 participants had incident CVD, and 391 died due to CVD. In multivariable Cox regression models, lower delta wave entropy during sleep was associated with higher risk of coronary heart disease (SHHS: HR: 1.46; 95% CI: 1.02-2.06; P = 0.03; MrOS: HR: 1.79; 95% CI: 1.17-2.73; P < 0.01), CVD (SHHS: HR: 1.60; 95% CI: 1.21-2.11; P < 0.01; MrOS: HR: 1.43; 95% CI: 1.00-2.05; P = 0.05), and CVD mortality (SHHS: HR: 1.94; 95% CI: 1.18-3.18; P < 0.01; MrOS: HR: 1.66; 95% CI: 1.12-2.47; P = 0.01) after adjusting for covariates. The Shapley Additive Explanations method indicates that low delta wave entropy was more predictive of coronary heart disease, CVD, and CVD mortality risks than conventional sleep parameters. CONCLUSIONS The results suggest that delta wave activity disruption during sleep may be a useful metric to identify those at increased risk for CVD and CVD mortality.
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Affiliation(s)
- Sizhi Ai
- Center for Sleep and Circadian Medicine, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China; Department of Cardiology, Heart Center, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, China.
| | - Shuo Ye
- Department of Cardiology, Heart Center, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, China
| | - Guohua Li
- Department of Cardiology, Heart Center, The First Affiliated Hospital of Xinxiang Medical University, Weihui, Henan, China
| | - Yue Leng
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, California, USA
| | - Katie L Stone
- Department of Epidemiology and Biostatistics, University of California-San Francisco, San Francisco, CA, USA
| | - Min Zhang
- School of Cardiovascular and Metabolic Medicine and Sciences, King's College London British Heart Foundation Centre of Research Excellence, London, UK
| | - Yun-Kwok Wing
- Li Chiu Kong Family Sleep Assessment Unit, Department of Psychiatry, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Jihui Zhang
- Center for Sleep and Circadian Medicine, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Yannis Yan Liang
- Center for Sleep and Circadian Medicine, The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.
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Schmidig FJ, Ruch S, Henke K. Episodic long-term memory formation during slow-wave sleep. eLife 2024; 12:RP89601. [PMID: 38661727 PMCID: PMC11045222 DOI: 10.7554/elife.89601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024] Open
Abstract
We are unresponsive during slow-wave sleep but continue monitoring external events for survival. Our brain wakens us when danger is imminent. If events are non-threatening, our brain might store them for later consideration to improve decision-making. To test this hypothesis, we examined whether novel vocabulary consisting of simultaneously played pseudowords and translation words are encoded/stored during sleep, and which neural-electrical events facilitate encoding/storage. An algorithm for brain-state-dependent stimulation selectively targeted word pairs to slow-wave peaks or troughs. Retrieval tests were given 12 and 36 hr later. These tests required decisions regarding the semantic category of previously sleep-played pseudowords. The sleep-played vocabulary influenced awake decision-making 36 hr later, if targeted to troughs. The words' linguistic processing raised neural complexity. The words' semantic-associative encoding was supported by increased theta power during the ensuing peak. Fast-spindle power ramped up during a second peak likely aiding consolidation. Hence, new vocabulary played during slow-wave sleep was stored and influenced decision-making days later.
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Affiliation(s)
| | - Simon Ruch
- Institute of Psychology, University of BernBernSwitzerland
- Faculty of Psychology, UniDistance SuisseBrigSwitzerland
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9
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Yang Q, Liu L, Wang J, Zhang Y, Jiang N, Zhang M. Wavelet Entropy Analysis of Electroencephalogram Signals During Wake and Different Sleep Stages in Patients with Insomnia Disorder. Nat Sci Sleep 2024; 16:347-358. [PMID: 38606372 PMCID: PMC11007398 DOI: 10.2147/nss.s452017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/22/2024] [Indexed: 04/13/2024] Open
Abstract
Objective To investigate the changes in the wavelet entropy during wake and different sleep stages in patients with insomnia disorder. Methods Sixteen patients with insomnia disorder and sixteen normal controls were enrolled. They underwent scale assessment and two consecutive nights of polysomnography (PSG). Wavelet entropy analysis of electroencephalogram (EEG) signals recorded from all participants in the two groups was performed. The changes in the integral wavelet entropy (En) and individual-scale wavelet entropy (En(a)) during wake and different sleep stages in the two groups were observed, and the differences between the two groups were compared. Results The insomnia disorder group exhibited lower En during the wake stage, and higher En during the N3 stage compared with the normal control group (all P < 0.001). In terms of En(a), patients with insomnia disorder exhibited lower En(a) in the β and α frequency bands during the wake stage compared with normal controls (β band, P < 0.01; α band, P < 0.001), whereas they showed higher En(a) in the β and α frequency bands during the N3 stage than normal controls (β band, P < 0.001; α band, P < 0.001). Conclusion Wavelet entropy can reflect the changes in the complexity of EEG signals during wake and different sleep stages in patients with insomnia disorder, which provides a new method and insights about understanding of pathophysiological mechanisms of insomnia disorder. Wavelet entropy provides an objective indicator for assessing sleep quality.
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Affiliation(s)
- Qian Yang
- Tianjin Union Medical Center, Tianjin Medical University, Tianjin, 300070, People’s Republic of China
| | - Lingfeng Liu
- Tianjin Union Medical Center, Tianjin Medical University, Tianjin, 300070, People’s Republic of China
| | - Jing Wang
- Department of Neurology, Tianjin Union Medical Center, Tianjin, 300121, People’s Republic of China
| | - Ying Zhang
- Department of Neurology, Tianjin Union Medical Center, Tianjin, 300121, People’s Republic of China
| | - Nan Jiang
- School of Mechanical Engineering, Tianjin University, Tianjin, 300354, People’s Republic of China
| | - Meiyun Zhang
- Department of Neurology, Tianjin Union Medical Center, Tianjin, 300121, People’s Republic of China
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Höhn C, Hahn MA, Lendner JD, Hoedlmoser K. Spectral Slope and Lempel-Ziv Complexity as Robust Markers of Brain States during Sleep and Wakefulness. eNeuro 2024; 11:ENEURO.0259-23.2024. [PMID: 38471778 PMCID: PMC10978822 DOI: 10.1523/eneuro.0259-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 01/22/2024] [Accepted: 02/09/2024] [Indexed: 03/14/2024] Open
Abstract
Nonoscillatory measures of brain activity such as the spectral slope and Lempel-Ziv complexity are affected by many neurological disorders and modulated by sleep. A multitude of frequency ranges, particularly a broadband (encompassing the full spectrum) and a narrowband approach, have been used especially for estimating the spectral slope. However, the effects of choosing different frequency ranges have not yet been explored in detail. Here, we evaluated the impact of sleep stage and task engagement (resting, attention, and memory) on slope and complexity in a narrowband (30-45 Hz) and broadband (1-45 Hz) frequency range in 28 healthy male human subjects (21.54 ± 1.90 years) using a within-subject design over 2 weeks with three recording nights and days per subject. We strived to determine how different brain states and frequency ranges affect slope and complexity and how the two measures perform in comparison. In the broadband range, the slope steepened, and complexity decreased continuously from wakefulness to N3 sleep. REM sleep, however, was best discriminated by the narrowband slope. Importantly, slope and complexity also differed between tasks during wakefulness. While narrowband complexity decreased with task engagement, the slope flattened in both frequency ranges. Interestingly, only the narrowband slope was positively correlated with task performance. Our results show that slope and complexity are sensitive indices of brain state variations during wakefulness and sleep. However, the spectral slope yields more information and could be used for a greater variety of research questions than Lempel-Ziv complexity, especially when a narrowband frequency range is used.
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Affiliation(s)
- Christopher Höhn
- Laboratory for Sleep, Cognition and Consciousness Research, Department of Psychology, University of Salzburg, 5020 Salzburg, Austria
- Centre for Cognitive Neuroscience Salzburg (CCNS), University of Salzburg, 5020 Salzburg, Austria
| | - Michael A Hahn
- Hertie-Institute for Clinical Brain Research, University Medical Center Tübingen, 72076 Tübingen, Germany
| | - Janna D Lendner
- Hertie-Institute for Clinical Brain Research, University Medical Center Tübingen, 72076 Tübingen, Germany
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Tübingen, 72076 Tübingen, Germany
| | - Kerstin Hoedlmoser
- Laboratory for Sleep, Cognition and Consciousness Research, Department of Psychology, University of Salzburg, 5020 Salzburg, Austria
- Centre for Cognitive Neuroscience Salzburg (CCNS), University of Salzburg, 5020 Salzburg, Austria
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11
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Zhang Y, Han X, Ge X, Xu T, Wang Y, Mu J, Liu F. Modular brain network in volitional eyes closing: enhanced integration with a marked impact on hubs. Cereb Cortex 2024; 34:bhad464. [PMID: 38044477 DOI: 10.1093/cercor/bhad464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/12/2023] [Accepted: 11/13/2023] [Indexed: 12/05/2023] Open
Abstract
Volitional eyes closing would shift brain's information processing modes from the "exteroceptive" to "interoceptive" state. This transition induced by the eyes closing is underpinned by a large-scale reconfiguration of brain network, which is still not fully comprehended. Here, we investigated the eyes-closing-relevant network reconfiguration by examining the functional integration among intrinsic modules. Our investigation utilized a publicly available dataset with 48 subjects being scanned in both eyes closed and eyes open conditions. It was found that the modular integration was significantly enhanced during the eyes closing, including lower modularity index, higher participation coefficient, less provincial hubs, and more connector hubs. Moreover, the eyes-closing-enhanced integration was particularly noticeable in the hubs of network, mainly located in the default-mode network. Finally, the hub-dominant modular enhancement was positively correlated to the eyes-closing-reduced entropy of BOLD signal, suggesting a close connection to the diminished consciousness of individuals. Collectively, our findings strongly suggested that the enhanced modular integration with substantially reorganized hubs characterized the large-scale cortical underpinning of the volitional eyes closing.
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Affiliation(s)
- Yi Zhang
- State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China
- Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Xiao Han
- Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Xuelian Ge
- Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Tianyong Xu
- Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Yanjie Wang
- Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Jiali Mu
- Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou 310027, China
| | - Fan Liu
- Bio-X Laboratory, Department of Physics, Zhejiang University, Hangzhou 310027, China
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12
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Wang G, Chen Y, Liu H, Yu X, Han Y, Wang W, Kang H. Differences in intestinal motility during different sleep stages based on long-term bowel sounds. Biomed Eng Online 2023; 22:105. [PMID: 37919731 PMCID: PMC10623717 DOI: 10.1186/s12938-023-01166-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/17/2023] [Indexed: 11/04/2023] Open
Abstract
BACKGROUND AND OBJECTIVES This study focused on changes in intestinal motility during different sleep stages based on long-term bowel sounds. METHODS A modified higher order statistics algorithm was devised to identify the effective bowel sound segments. Next, characteristic values (CVs) were extracted from each bowel sound segment, which included 4 time-domain, 4 frequency-domain and 2 nonlinear CVs. The statistical analysis of these CVs corresponding to the different sleep stages could be used to evaluate the changes in intestinal motility during sleep. RESULTS A total of 6865.81 min of data were recorded from 14 participants, including both polysomnographic data and bowel sound data which were recorded simultaneously from each participant. The average accuracy, sensitivity and specificity of the modified higher order statistics detector were 96.46 ± 2.60%, 97.24 ± 2.99% and 94.13 ± 4.37%. In addition, 217088 segments of effective bowel sound corresponding to different sleep stages were identified using the modified detector. Most of the CVs were statistically different during different sleep stages ([Formula: see text]). Furthermore, the bowel sounds were low in frequency based on frequency-domain CVs, high in energy based on time-domain CVs and low in complexity base on nonlinear CVs during deep sleep, which was consistent with the state of the EEG signals during deep sleep. CONCLUSIONS The intestinal motility varies by different sleep stages based on long-term bowel sounds using the modified higher order statistics detector. The study indicates that the long-term bowel sounds can well reflect intestinal motility during sleep. This study also demonstrates that it is technically feasible to simultaneously record intestinal motility and sleep state throughout the night. This offers great potential for future studies investigating intestinal motility during sleep and related clinical applications.
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Affiliation(s)
- Guojing Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- Key Laboratory of Biomedical Engineering and Translational Medicine, Ministry of Industry and Information Technology, Chinese PLA General Hospital, Beijing, China
- Bioengineering Research Center, Medical Innovation Research Division, Chinese PLA General Hospital, Beijing, China
| | - Yibing Chen
- Department of Pulmonary and Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| | - Hongyun Liu
- Key Laboratory of Biomedical Engineering and Translational Medicine, Ministry of Industry and Information Technology, Chinese PLA General Hospital, Beijing, China
- Bioengineering Research Center, Medical Innovation Research Division, Chinese PLA General Hospital, Beijing, China
| | - Xiaohua Yu
- Key Laboratory of Biomedical Engineering and Translational Medicine, Ministry of Industry and Information Technology, Chinese PLA General Hospital, Beijing, China
- Bioengineering Research Center, Medical Innovation Research Division, Chinese PLA General Hospital, Beijing, China
| | - Yi Han
- Key Laboratory of Biomedical Engineering and Translational Medicine, Ministry of Industry and Information Technology, Chinese PLA General Hospital, Beijing, China
- Bioengineering Research Center, Medical Innovation Research Division, Chinese PLA General Hospital, Beijing, China
| | - Weidong Wang
- Key Laboratory of Biomedical Engineering and Translational Medicine, Ministry of Industry and Information Technology, Chinese PLA General Hospital, Beijing, China.
- Bioengineering Research Center, Medical Innovation Research Division, Chinese PLA General Hospital, Beijing, China.
| | - Hongyan Kang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
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13
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Yao W, Yao W, Wang J. Threshold distribution of equal states for quantitative amplitude fluctuations. Physiol Meas 2023; 44:095004. [PMID: 37666257 DOI: 10.1088/1361-6579/acf6a6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 09/04/2023] [Indexed: 09/06/2023]
Abstract
Objective. The distribution of equal states (DES) quantifies amplitude fluctuations in biomedical signals. However, under certain conditions, such as a high resolution of data collection or special signal processing techniques, equal states may be very rare, whereupon the DES fails to measure the amplitude fluctuations.Approach. To address this problem, we develop a novel threshold DES (tDES) that measures the distribution of differential states within a threshold. To evaluate the proposed tDES, we first analyze five sets of synthetic signals generated in different frequency bands. We then analyze sleep electroencephalography (EEG) datasets taken from the public PhysioNet.Main results. Synthetic signals and detrend-filtered sleep EEGs have no neighboring equal values; however, tDES can effectively measure the amplitude fluctuations within these data. The tDES of EEG data increases significantly as the sleep stage increases, even with datasets covering very short periods, indicating decreased amplitude fluctuations in sleep EEGs. Generally speaking, the presence of more low-frequency components in a physiological series reflects smaller amplitude fluctuations and larger DES.Significance. The tDES provides a reliable computing method for quantifying amplitude fluctuations, exhibiting the characteristics of conceptual simplicity and computational robustness. Our findings broaden the application of quantitative amplitude fluctuations and contribute to the classification of sleep stages based on EEG data.
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Affiliation(s)
- Wenpo Yao
- School of Geographic and Biologic Information, Smart Health Big Data Analysis and Location Services Engineering Lab of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
- Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, People's Republic of China
| | - Wenli Yao
- State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Jun Wang
- School of Geographic and Biologic Information, Smart Health Big Data Analysis and Location Services Engineering Lab of Jiangsu Province, Nanjing University of Posts and Telecommunications, Nanjing 210023, People's Republic of China
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14
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Jacob MS, Sargent K, Roach BJ, Shamshiri EA, Mathalon DH, Ford JM. The Scanner as the Stimulus: Deficient Gamma-BOLD Coupling in Schizophrenia at Rest. Schizophr Bull 2023; 49:1364-1374. [PMID: 37098100 PMCID: PMC10483456 DOI: 10.1093/schbul/sbad014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Functional magnetic resonance imaging (fMRI) scanners are unavoidably loud and uncomfortable experimental tools that are necessary for schizophrenia (SZ) neuroscience research. The validity of fMRI paradigms might be undermined by well-known sensory processing abnormalities in SZ that could exert distinct effects on neural activity in the presence of scanner background sound. Given the ubiquity of resting-state fMRI (rs-fMRI) paradigms in SZ research, elucidating the relationship between neural, hemodynamic, and sensory processing deficits during scanning is necessary to refine the construct validity of the MR neuroimaging environment. We recorded simultaneous electroencephalography (EEG)-fMRI at rest in people with SZ (n = 57) and healthy control participants without a psychiatric diagnosis (n = 46) and identified gamma EEG activity in the same frequency range as the background sounds emitted from our scanner during a resting-state sequence. In participants with SZ, gamma coupling to the hemodynamic signal was reduced in bilateral auditory regions of the superior temporal gyri. Impaired gamma-hemodynamic coupling was associated with sensory gating deficits and worse symptom severity. Fundamental sensory-neural processing deficits in SZ are present at rest when considering scanner background sound as a "stimulus." This finding may impact the interpretation of rs-fMRI activity in studies of people with SZ. Future neuroimaging research in SZ might consider background sound as a confounding variable, potentially related to fluctuations in neural excitability and arousal.
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Affiliation(s)
- Michael S Jacob
- Mental Health Service, San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA 94121, USA
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Kaia Sargent
- Mental Health Service, San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA 94121, USA
| | - Brian J Roach
- Mental Health Service, San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA 94121, USA
| | - Elhum A Shamshiri
- Mental Health Service, San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA 94121, USA
| | - Daniel H Mathalon
- Mental Health Service, San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA 94121, USA
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Judith M Ford
- Mental Health Service, San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA 94121, USA
- Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
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15
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Feng YZ, Chen JT, Hu ZY, Liu GX, Zhou YS, Zhang P, Su AX, Yang S, Zhang YM, Wei RM, Chen GH. Effects of Sleep Reactivity on Sleep Macro-Structure, Orderliness, and Cortisol After Stress: A Preliminary Study in Healthy Young Adults. Nat Sci Sleep 2023; 15:533-546. [PMID: 37434994 PMCID: PMC10332417 DOI: 10.2147/nss.s415464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/29/2023] [Indexed: 07/13/2023] Open
Abstract
Purpose To investigate changes and links of stress and high sleep reactivity (H-SR) on the macro-structure and orderliness of sleep and cortisol levels in good sleepers (GS). Patients and Methods Sixty-two GS (18-40 years old) were recruited, with 32 in the stress group and 30 in the control group. Each group was further divided into H-SR and low SR subgroups based on the Ford Insomnia Response to Stress Test. All participants completed two nights of polysomnography in a sleep laboratory. Before conducting polysomnography on the second night, the stress group completed the Trier Social Stress Test and saliva was collected. Results The duration of NREM sleep stages 1, 2 (N1, N2) and rapid eye movement sleep (REM) decreased, and the values of approximate entropy, sample entropy, fuzzy entropy, and multiscale entropy increased under stress and SR effects. Stress increased rapid eye movement density, and H-SR increased cortisol reactivity. Conclusion Stress can damage the sleep and increase cortisol release in GS, especially those with H-SR. N1, N2 and REM sleep are more easily affected, while NREM sleep stage 3 sleep is relatively stable.
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Affiliation(s)
- Yi-Zhou Feng
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Jun-Tao Chen
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
- Department of Neurology, Shangyu People’s Hospital of Shaoxing, Shaoxing, Zhejiang, 312000, People’s Republic of China
| | - Zhen-Yu Hu
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Gao-Xia Liu
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Yu-Shun Zhou
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Ping Zhang
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Ai-Xi Su
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Shuai Yang
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Yue-Ming Zhang
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Ru-Meng Wei
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
| | - Gui-Hai Chen
- Department of Neurology (Sleep Disorders), Chaohu Hospital of Anhui Medical University, Hefei, Anhui, 238000, People’s Republic of China
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Hernandez CI, Kargarnovin S, Hejazi S, Karwowski W. Examining electroencephalogram signatures of people with multiple sclerosis using a nonlinear dynamics approach: a systematic review and bibliographic analysis. Front Comput Neurosci 2023; 17:1207067. [PMID: 37457899 PMCID: PMC10344458 DOI: 10.3389/fncom.2023.1207067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 06/14/2023] [Indexed: 07/18/2023] Open
Abstract
Background Considering that brain activity involves communication between millions of neurons in a complex network, nonlinear analysis is a viable tool for studying electroencephalography (EEG). The main objective of this review was to collate studies that utilized chaotic measures and nonlinear dynamical analysis in EEG of multiple sclerosis (MS) patients and to discuss the contributions of chaos theory techniques to understanding, diagnosing, and treating MS. Methods Using the preferred reporting items for systematic reviews and meta-analysis (PRISMA), the databases EbscoHost, IEEE, ProQuest, PubMed, Science Direct, Web of Science, and Google Scholar were searched for publications that applied chaos theory in EEG analysis of MS patients. Results A bibliographic analysis was performed using VOSviewer software keyword co-occurrence analysis indicated that MS was the focus of the research and that research on MS diagnosis has shifted from conventional methods, such as magnetic resonance imaging, to EEG techniques in recent years. A total of 17 studies were included in this review. Among the included articles, nine studies examined resting-state, and eight examined task-based conditions. Conclusion Although nonlinear EEG analysis of MS is a relatively novel area of research, the findings have been demonstrated to be informative and effective. The most frequently used nonlinear dynamics analyses were fractal dimension, recurrence quantification analysis, mutual information, and coherence. Each analysis selected provided a unique assessment to fulfill the objective of this review. While considering the limitations discussed, there is a promising path forward using nonlinear analyses with MS data.
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17
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Ma Y, Chang MC, Litrownik D, Wayne PM, Yeh GY. Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease. J Clin Sleep Med 2023; 19:873-882. [PMID: 36692177 PMCID: PMC10152358 DOI: 10.5664/jcsm.10434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 12/05/2022] [Accepted: 12/05/2022] [Indexed: 01/25/2023]
Abstract
STUDY OBJECTIVES Heart rate variability (HRV) measures provide valuable insights into physiology; however, gaps remain in understanding circadian patterns in heart rate dynamics. We aimed to explore day-night differences in heart rate dynamics in patients with chronic cardiopulmonary disease compared with healthy controls. METHODS Using 24-hour heart rate data from patients with chronic obstructive pulmonary disease (COPD) and/or heart failure (n = 16) and healthy adult controls (older group: ≥50 years, n = 42; younger group: 20-49 years, n = 136), we compared day-night differences in conventional time and frequency domain HRV indices and a multiscale-entropy-based complexity index (CI1-20) of HRV among the 3 groups. RESULTS Twenty-four-hour HRV showed significant day-night differences (marked with "△") among younger healthy (mean age: 34.5 years), older healthy (mean age: 61.6 years), and cardiopulmonary patients (mean age: 68.4 years), including change in percentage of adjacent intervals that differ > 50 ms (△pNN50), high frequency (△HF), normalized low frequency (△nLF), ratio (△LF/HF), and △CI1-20. Among these, △LF/HF (2.13 ± 2.35 vs 1.1 ± 2.47 vs -0.35 ± 1.25; P < .001) and △CI1-20 (0.15 ± 0.24 vs 0.02 ± 0.28 vs -0.21 ± 0.27; P < .001) were significant in each pairwise comparison following analysis of variance tests. Average CI1-20 was highest in younger healthy individuals and lowest in cardiopulmonary patients (1.37 ± 0.12 vs 1.01 ± 0.27; P < .001). Younger healthy patients showed a heart rate complexity dipping pattern (night < day), older healthy patients showed nondipping, and cardiopulmonary patients showed reverse dipping (night > day). CONCLUSIONS As measures of 24-hour variability, traditional and complexity-based metrics of HRV exhibit large day-night differences in healthy individuals; these differences are blunted, or even reversed, in individuals with cardiopulmonary pathology. Measures of diurnal dynamics may be useful indices of reduced adaptive capacity in patients with cardiopulmonary conditions. CITATION Ma Y, Chang M-C, Litrownik D, Wayne PM, Yeh GY. Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease. J Clin Sleep Med. 2023;19(5):873-882.
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Affiliation(s)
- Yan Ma
- Osher Center for Integrative Medicine, Division of Preventive Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Mei-Chu Chang
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Daniel Litrownik
- Osher Center for Integrative Medicine, Division of Preventive Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
- Division of General Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Peter M. Wayne
- Osher Center for Integrative Medicine, Division of Preventive Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Gloria Y. Yeh
- Osher Center for Integrative Medicine, Division of Preventive Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
- Division of General Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
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18
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Armonaite K, Nobili L, Paulon L, Balsi M, Conti L, Tecchio F. Local neurodynamics as a signature of cortical areas: new insights from sleep. Cereb Cortex 2023; 33:3284-3292. [PMID: 35858209 DOI: 10.1093/cercor/bhac274] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 06/02/2022] [Accepted: 06/04/2022] [Indexed: 11/13/2022] Open
Abstract
Sleep crucial for the animal survival is accompanied by huge changes in neuronal electrical activity over time, the neurodynamics. Here, drawing on intracranial stereo-electroencephalographic (sEEG) recordings from the Montreal Neurological Institute (MNI), we analyzed local neurodynamics in the waking state at rest and during the N2, N3, and rapid eye movement (REM) sleep phases. Higuchi fractal dimension (HFD)-a measure of signal complexity-was studied as a feature of the local neurodynamics of the primary motor (M1), somatosensory (S1), and auditory (A1) cortices. The key working hypothesis, that the relationships between local neurodynamics preserve in all sleep phases despite the neurodynamics complexity reduces in sleep compared with wakefulness, was supported by the results. In fact, while HFD awake > REM > N2 > N3 (P < 0.001 consistently), HFD in M1 > S1 > A1 in awake and all sleep stages (P < 0.05 consistently). Also power spectral density was studied for consistency with previous investigations. Meaningfully, we found a local specificity of neurodynamics, well quantified by the fractal dimension, expressed in wakefulness and during sleep. We reinforce the idea that neurodynamic may become a new criterion for cortical parcellation, prospectively improving the understanding and ability of compensatory interventions for behavioral disorders.
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Affiliation(s)
- Karolina Armonaite
- Faculty of Psychology, Uninettuno University, Corso V. Emanuele II, n. 39, 00186, Rome, Italy
- Laboratory of Electrophysiology for Translational NeuroScience (LET'S), Institute of Cognitive Sciences and Technologies - Consiglio Nazionale delle Ricerche, Via Palestro, n. 32, 00185, Rome, Italy
| | - Lino Nobili
- Child Neurology and Psychiatry, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini, n. 5, 16147, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics and Maternal and Child Health (DINOGMI), University of Genoa, Largo Paolo Daneo, n. 3, 16132, Genoa, Italy
| | - Luca Paulon
- Laboratory of Electrophysiology for Translational NeuroScience (LET'S), Institute of Cognitive Sciences and Technologies - Consiglio Nazionale delle Ricerche, Via Palestro, n. 32, 00185, Rome, Italy
| | - Marco Balsi
- Department of Information Engineering, Electronics and Telecommunications, Sapienza University, Via Eudossiana, n. 18, 00184, Rome
| | - Livio Conti
- Faculty of Engineering, Uninettuno University, Corso V. Emanuele II, n. 39, 00186, Rome, Italy
- INFN - Istituto Nazionale di Fisica Nucleare, Sezione Roma Tor Vergata, Via della Ricerca Scientifica, n.1, 00133, Rome, Italy
| | - Franca Tecchio
- Laboratory of Electrophysiology for Translational NeuroScience (LET'S), Institute of Cognitive Sciences and Technologies - Consiglio Nazionale delle Ricerche, Via Palestro, n. 32, 00185, Rome, Italy
- Faculty of Psychology, Uninettuno University, Corso V. Emanuele II, n. 39, 00186, Rome, Italy
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Zhao X, Jin F, Wang J, Zhao X, Wang L, Wei H. Entropy of left ventricular late gadolinium enhancement and its prognostic value in hypertrophic cardiomyopathy a new CMR assessment method. Int J Cardiol 2023; 373:134-141. [PMID: 36395920 DOI: 10.1016/j.ijcard.2022.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/04/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022]
Abstract
PURPOSE As a novel metric, entropy generated from late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) can be utilized to assess tissue heterogeneity. However, it is unknown if it can be utilized for risk stratification in hypertrophic cardiomyopathy (HCM). In addition, it is unknown if LGE entropy correlates with LGE mass%, which is commonly utilized for fibrosis assessment. This research was done to investigate these issues. MATERIALS AND METHODS Patients with HCM who underwent 3.0-T CMR between January 2015 and January 2020 were prospectively enrolled and classified into low- and high-risk groups according to the AHA/ACC risk stratification guideline for 2020. The LGE entropy was automatically estimated using a generic Python package algorithm. On CMR imaging, the LGE mass% was determined using the CVI 42 software. Endpoint events included sudden cardiac death (SCD), hospital readmission owing to heart failure, and implantable cardioverter defibrillator (ICD) treatment for ventricular arrhythmias. RESULTS A total of 109 HCM participants (70 males) were included. During the follow-up (23 ± 7 months), the patients in the high-risk group had higher LGE entropy (p < 0.001) and LGE mass% (p < 0.001) than those in the low-risk group, and patients with endpoint events had higher LGE entropy (p < 0.001) and LGE mass% (p < 0.001) than those without endpoint events. In all participants, there was a link between LGE entropy and LGE mass%, according to the Spearman rank correlation analysis (p < 0.001; r = 0.667). In ROC analysis, the area under the curve (AUC) of LGE entropy was 0.893 (95% CI, 0.794-0.993; P<0.001), AUC of LGE mass% was 0.826 (95% CI, 0.737-0.914; P<0.001), AUC of LVEF was 0.610 (95% CI, 0.473-0.748; P = 0.117) and AUC of 2020 AHA/ACC guideline for risk stratification was 0.716 (95% CI, 0.617-0.815; P = 0.002). According to Kaplan-Meier curves, HCM with a higher LGE entropy (≥cutoff value (<5.873) or ≥ thied tertile (5.540)) were more likely to experience the endpoint events. Following adjustment for the 2020 AHA/ACC guideline for risk categorization, LGE mass%, or decreased LVEF, Cox analysis showed that LGE entropy was independently linked with endpoint events. CONCLUSIONS The variability and extent of LGE pictures can be reflected by LGE entropy, which is a reliable, usable, and repeatable metric for risk classification in HCM. It is a prognostic indicator of endpoint events that is independent of other risk indicators.
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Affiliation(s)
- Xiaoying Zhao
- Department of Radiology, The Second Affiliated Hospital of Kunming Medical University, Dianmiandadao No. 374, Kunming, Yunnan 650000, China
| | - Fuwei Jin
- Department of Radiology, The Second Affiliated Hospital of Kunming Medical University, Dianmiandadao No. 374, Kunming, Yunnan 650000, China
| | - Jin Wang
- Department of Radiology, Yanan Hospital of Kunming City, Renmin Dong Lu No. 245, Kunming, Yunnan 650000, China.
| | - Xinxiang Zhao
- Department of Radiology, The Second Affiliated Hospital of Kunming Medical University, Dianmiandadao No. 374, Kunming, Yunnan 650000, China.
| | - Lujing Wang
- Department of Radiology, The Second Affiliated Hospital of Kunming Medical University, Dianmiandadao No. 374, Kunming, Yunnan 650000, China
| | - Hua Wei
- Department of Information, The Second Affiliated Hospital of Kunming Medical University,Dianmiandadao No. 374, Kunming, Yunnan 650000, China
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Wang X, Bik A, de Groot ER, Tataranno ML, Benders MJNL, Dudink J. Feasibility of automated early postnatal sleep staging in extremely and very preterm neonates using dual-channel EEG. Clin Neurophysiol 2023; 146:55-64. [PMID: 36535092 DOI: 10.1016/j.clinph.2022.11.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 10/25/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To investigate the feasibility of automated sleep staging based on quantitative analysis of dual-channel electroencephalography (EEG) for extremely and very preterm infants during their first postnatal days. METHODS We enrolled 17 preterm neonates born between 25 and 30 weeks of gestational age. Three-hour behavioral sleep observations and simultaneous dual-channel EEG monitoring were conducted for each infant within their first 72 hours after birth. Four kinds of representative and complementary quantitative EEG (qEEG) metrics (i.e., bursting, synchrony, spectral power, and complexity) were calculated and compared between active sleep, quiet sleep, and wakefulness. All analyses were performed in offline mode. RESULTS In separate comparison analyses, significant differences between sleep-wake states were found for bursting, spectral power and complexity features. The automated sleep-wake state classifier based on the combination of all qEEG features achieved a macro-averaged area under the curve of receiver operating characteristic of 74.8%. The complexity features contributed the most to sleep-wake state classification. CONCLUSIONS It is feasible to distinguish between sleep-wake states within the first 72 postnatal hours for extremely and very preterm infants using qEEG metrics. SIGNIFICANCE Our findings offer the possibility of starting personalized care dependent on preterm infants' sleep-wake states directly after birth, potentially yielding long-run benefits for their developmental outcomes.
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Affiliation(s)
- Xiaowan Wang
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Anne Bik
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Eline R de Groot
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Maria Luisa Tataranno
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands; Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Manon J N L Benders
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands; Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jeroen Dudink
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands; Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
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21
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Zheng J, Li Y, Zhai Y, Zhang N, Yu H, Tang C, Yan Z, Luo E, Xie K. Effects of sampling rate on multiscale entropy of electroencephalogram time series. Biocybern Biomed Eng 2023. [DOI: 10.1016/j.bbe.2022.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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22
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Lau ZJ, Pham T, Chen SHA, Makowski D. Brain entropy, fractal dimensions and predictability: A review of complexity measures for EEG in healthy and neuropsychiatric populations. Eur J Neurosci 2022; 56:5047-5069. [PMID: 35985344 PMCID: PMC9826422 DOI: 10.1111/ejn.15800] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/20/2022] [Accepted: 08/10/2022] [Indexed: 01/11/2023]
Abstract
There has been an increasing trend towards the use of complexity analysis in quantifying neural activity measured by electroencephalography (EEG) signals. On top of revealing complex neuronal processes of the brain that may not be possible with linear approaches, EEG complexity measures have also demonstrated their potential as biomarkers of psychopathology such as depression and schizophrenia. Unfortunately, the opacity of algorithms and descriptions originating from mathematical concepts have made it difficult to understand what complexity is and how to draw consistent conclusions when applied within psychology and neuropsychiatry research. In this review, we provide an overview and entry-level explanation of existing EEG complexity measures, which can be broadly categorized as measures of predictability and regularity. We then synthesize complexity findings across different areas of psychological science, namely, in consciousness research, mood and anxiety disorders, schizophrenia, neurodevelopmental and neurodegenerative disorders, as well as changes across the lifespan, while addressing some theoretical and methodological issues underlying the discrepancies in the data. Finally, we present important considerations when choosing and interpreting these metrics.
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Affiliation(s)
- Zen J. Lau
- School of Social SciencesNanyang Technological UniversitySingapore
| | - Tam Pham
- School of Social SciencesNanyang Technological UniversitySingapore
| | - S. H. Annabel Chen
- School of Social SciencesNanyang Technological UniversitySingapore,Centre for Research and Development in LearningNanyang Technological UniversitySingapore,Lee Kong Chian School of MedicineNanyang Technological UniversitySingapore,National Institute of EducationNanyang Technological UniversitySingapore
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23
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Melo IO, Angelo Mendes Tenorio FDC, da Silva Gomes JA, da Silva Junior VA, de Albuquerque Nogueira R, Tenorio BM. Fractal methods applied to the seminiferous lumen images can quantify testicular changes induced by heat stress. Acta Histochem 2022; 124:151949. [PMID: 36007436 DOI: 10.1016/j.acthis.2022.151949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/03/2022] [Accepted: 08/05/2022] [Indexed: 11/25/2022]
Abstract
Male infertility affects many couples around the world and can be related to environmental factors such as exposure to high temperatures. Even so, automated methods evaluating the seminiferous tubules to detect testicular damage are still scarce. In search of new approaches to automation in the microscopic analysis of the testis; the present study used the fractal dimension, lacunarity, multifractality and quantitative morphometry to quantify changes in microphotographs of the seminiferous lumen in testicles reversibly damaged by heat stress (43 °C, 12 min). The parameters fractal dimension, lacunarity, multifractality (Dq and α), perimeter, feret and circularity were able to detect changes in the seminiferous lumen at 7, 15 and 30 days after the testicular damage. These methods also detected the recovery of spermatogenesis at 60 days after heat stress. Area, f(α), centroid X and Y, roundness, rectangle height and width were unable to detect changes caused by heat stress. In conclusion, computer assisted methods applied to the seminiferous lumen images can be a useful new viewpoint to analyze microscopic changes in the testicles, a fast low-cost tool to assist in the automated quantification of testicular damage.
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Affiliation(s)
- Isabel Oliveira Melo
- Health Sciences Center, Federal University of Paraíba, João Pessoa, Paraíba, Brazil
| | | | - José Anderson da Silva Gomes
- Department of Histology and Embryology, Bioscience Center, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | | | | | - Bruno Mendes Tenorio
- Department of Histology and Embryology, Bioscience Center, Federal University of Pernambuco, Recife, Pernambuco, Brazil.
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24
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Automatic sleep stage classification: From classical machine learning methods to deep learning. Biomed Signal Process Control 2022. [DOI: 10.1016/j.bspc.2022.103751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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25
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Geng D, Wang C, Fu Z, Zhang Y, Yang K, An H. Sleep EEG-Based Approach to Detect Mild Cognitive Impairment. Front Aging Neurosci 2022; 14:865558. [PMID: 35493944 PMCID: PMC9045132 DOI: 10.3389/fnagi.2022.865558] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/07/2022] [Indexed: 11/25/2022] Open
Abstract
Mild Cognitive Impairment (MCI) is an early stage of dementia, which may lead to Alzheimer's disease (AD) in older adults. Therefore, early detection of MCI and implementation of treatment and intervention can effectively slow down or even inhibit the progression of the disease, thus minimizing the risk of AD. Currently, we know that published work relies on an analysis of awake EEG recordings. However, recent studies have suggested that changes in the structure of sleep may lead to cognitive decline. In this work, we propose a sleep EEG-based method for MCI detection, extracting specific features of sleep to characterize neuroregulatory deficit emergent with MCI. This study analyzed the EEGs of 40 subjects (20 MCI, 20 HC) with the developed algorithm. We extracted sleep slow waves and spindles features, combined with spectral and complexity features from sleep EEG, and used the SVM classifier and GRU network to identify MCI. In addition, the classification results of different feature sets (including with sleep features from sleep EEG and without sleep features from awake EEG) and different classification methods were evaluated. Finally, the MCI classification accuracy of the GRU network based on features extracted from sleep EEG was the highest, reaching 93.46%. Experimental results show that compared with the awake EEG, sleep EEG can provide more useful information to distinguish between MCI and HC. This method can not only improve the classification performance but also facilitate the early intervention of AD.
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Affiliation(s)
- Duyan Geng
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin, China
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin, China
| | - Chao Wang
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin, China
| | - Zhigang Fu
- Physical Examination Center, The 983 Hospital of Joint Logistics Support Force of the Chinese People’s Liberation Army, Tianjin, China
| | - Yi Zhang
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin, China
| | - Kai Yang
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin, China
| | - Hongxia An
- Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin, China
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26
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Baird B, Tononi G, LaBerge S. Lucid dreaming occurs in activated rapid eye movement sleep, not a mixture of sleep and wakefulness. Sleep 2022; 45:6528977. [PMID: 35167686 DOI: 10.1093/sleep/zsab294] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 11/10/2021] [Indexed: 01/29/2023] Open
Abstract
STUDY OBJECTIVES (1) To critically test whether a previously reported increase in frontolateral 40 Hz power in lucid REM sleep, used to justify the claim that lucid dreaming is a "hybrid state" mixing sleep and wakefulness, is attributable to the saccadic spike potential (SP) artifact as a corollary of heightened REM density. (2) To replicate the finding that lucid dreams are associated with physiological activation, including heightened eye movement density, during REM sleep. (3) To conduct an exploratory analysis of changes in EEG features during lucid REM sleep. METHODS We analyzed 14 signal-verified lucid dreams (SVLDs) and baseline REM sleep segments from the same REM periods from six participants derived from the Stanford SVLD database. Participants marked lucidity onset with standard left-right-left-right-center (LR2c) eye-movement signals in polysomnography recordings. RESULTS Compared to baseline REM sleep, lucid REM sleep had higher REM density (β = 0.85, p = 0.002). Bayesian analysis supported the null hypothesis of no differences in frontolateral 40 Hz power after removal of the SP artifact (BH = 0.18) and ICA correction (BH = 0.01). Compared to the entire REM sleep period, lucid REM sleep showed small reductions in low-frequency and beta band spectral power as well as increased signal complexity (all p < 0.05), which were within the normal variance of baseline REM sleep. CONCLUSIONS Lucid dreams are associated with higher-than-average levels of physiological activation during REM sleep, including measures of both subcortical and cortical activation. Increases in 40 Hz power in periorbital channels reflect saccadic and microsaccadic SPs as a result of higher REM density accompanying heightened activation.
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Affiliation(s)
- Benjamin Baird
- Department of Psychiatry, Center for Sleep and Consciousness, University of Wisconsin-Madison, Madison, WI, USA
| | - Giulio Tononi
- Department of Psychiatry, Center for Sleep and Consciousness, University of Wisconsin-Madison, Madison, WI, USA
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27
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Pascovich C, Castro-Zaballa S, Mediano PAM, Bor D, Canales-Johnson A, Torterolo P, Bekinschtein TA. Ketamine and sleep modulate neural complexity dynamics in cats. Eur J Neurosci 2022; 55:1584-1600. [PMID: 35263482 PMCID: PMC9310726 DOI: 10.1111/ejn.15646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 02/02/2022] [Accepted: 02/23/2022] [Indexed: 11/30/2022]
Abstract
There is increasing evidence that the level of consciousness can be captured by neural informational complexity: for instance, complexity, as measured by the Lempel Ziv (LZ) compression algorithm, decreases during anaesthesia and non‐rapid eye movement (NREM) sleep in humans and rats, when compared with LZ in awake and REM sleep. In contrast, LZ is higher in humans under the effect of psychedelics, including subanaesthetic doses of ketamine. However, it is both unclear how this result would be modulated by varying ketamine doses, and whether it would extend to other species. Here, we studied LZ with and without auditory stimulation during wakefulness and different sleep stages in five cats implanted with intracranial electrodes, as well as under subanaesthetic doses of ketamine (5, 10, and 15 mg/kg i.m.). In line with previous results, LZ was lowest in NREM sleep, but similar in REM and wakefulness. Furthermore, we found an inverted U‐shaped curve following different levels of ketamine doses in a subset of electrodes, primarily in prefrontal cortex. However, it is worth noting that the variability in the ketamine dose–response curve across cats and cortices was larger than that in the sleep‐stage data, highlighting the differential local dynamics created by two different ways of modulating conscious state. These results replicate previous findings, both in humans and other species, demonstrating that neural complexity is highly sensitive to capture state changes between wake and sleep stages while adding a local cortical description. Finally, this study describes the differential effects of ketamine doses, replicating a rise in complexity for low doses, and further fall as doses approach anaesthetic levels in a differential manner depending on the cortex.
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Affiliation(s)
- Claudia Pascovich
- Laboratory of Sleep Neurobiology, Department of Physiology, School of Medicine, Universidad de la República, Uruguay.,Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, UK
| | - Santiago Castro-Zaballa
- Laboratory of Sleep Neurobiology, Department of Physiology, School of Medicine, Universidad de la República, Uruguay
| | - Pedro A M Mediano
- Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, UK
| | - Daniel Bor
- Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, UK
| | - Andrés Canales-Johnson
- Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, UK.,Vicerrectoría de Investigación y Posgrado, Universidad Católica del Maule, Talca, Chile
| | - Pablo Torterolo
- Laboratory of Sleep Neurobiology, Department of Physiology, School of Medicine, Universidad de la República, Uruguay
| | - Tristan A Bekinschtein
- Consciousness and Cognition Laboratory, Department of Psychology, University of Cambridge, UK
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28
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Lu Y, Rodriguez-Larios J. Nonlinear EEG signatures of mind wandering during breath focus meditation. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100056. [DOI: 10.1016/j.crneur.2022.100056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022] Open
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Jacob MS, Roach BJ, Sargent KS, Mathalon DH, Ford JM. Aperiodic measures of neural excitability are associated with anticorrelated hemodynamic networks at rest: A combined EEG-fMRI study. Neuroimage 2021; 245:118705. [PMID: 34798229 DOI: 10.1016/j.neuroimage.2021.118705] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 10/11/2021] [Accepted: 11/01/2021] [Indexed: 11/24/2022] Open
Abstract
The hallmark of resting EEG spectra are distinct rhythms emerging from a broadband, aperiodic background. This aperiodic neural signature accounts for most of total EEG power, although its significance and relation to functional neuroanatomy remains obscure. We hypothesized that aperiodic EEG reflects a significant metabolic expenditure and therefore might be associated with the default mode network while at rest. During eyes-open, resting-state recordings of simultaneous EEG-fMRI, we find that aperiodic and periodic components of EEG power are only minimally associated with activity in the default mode network. However, a whole-brain analysis identifies increases in aperiodic power correlated with hemodynamic activity in an auditory-salience-cerebellar network, and decreases in aperiodic power are correlated with hemodynamic activity in prefrontal regions. Desynchronization in residual alpha and beta power is associated with visual and sensorimotor hemodynamic activity, respectively. These findings suggest that resting-state EEG signals acquired in an fMRI scanner reflect a balance of top-down and bottom-up stimulus processing, even in the absence of an explicit task.
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Affiliation(s)
- Michael S Jacob
- Mental Health Service, San Francisco Veterans Affairs Healthcare System, 4150 Clement St, San Francisco, CA 94121 United States; Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA 94143 United States.
| | - Brian J Roach
- Mental Health Service, San Francisco Veterans Affairs Healthcare System, 4150 Clement St, San Francisco, CA 94121 United States.
| | - Kaia S Sargent
- Mental Health Service, San Francisco Veterans Affairs Healthcare System, 4150 Clement St, San Francisco, CA 94121 United States.
| | - Daniel H Mathalon
- Mental Health Service, San Francisco Veterans Affairs Healthcare System, 4150 Clement St, San Francisco, CA 94121 United States; Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA 94143 United States.
| | - Judith M Ford
- Mental Health Service, San Francisco Veterans Affairs Healthcare System, 4150 Clement St, San Francisco, CA 94121 United States; Department of Psychiatry and Weill Institute for Neurosciences, University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA 94143 United States.
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30
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Liang Z. What Does Sleeping Brain Tell About Stress? A Pilot Functional Near-Infrared Spectroscopy Study Into Stress-Related Cortical Hemodynamic Features During Sleep. FRONTIERS IN COMPUTER SCIENCE 2021. [DOI: 10.3389/fcomp.2021.774949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
People with mental stress often experience disturbed sleep, suggesting stress-related abnormalities in brain activity during sleep. However, no study has looked at the physiological oscillations in brain hemodynamics during sleep in relation to stress. In this pilot study, we aimed to explore the relationships between bedtime stress and the hemodynamics in the prefrontal cortex during the first sleep cycle. We tracked the stress biomarkers, salivary cortisol, and secretory immunoglobulin A (sIgA) on a daily basis and utilized the days of lower levels of measured stress as natural controls to the days of higher levels of measured stress. Cortical hemodynamics was measured using a cutting-edge wearable functional near-infrared spectroscopy (fNIRS) system. Time-domain, frequency-domain features as well as nonlinear features were derived from the cleaned hemodynamic signals. We proposed an original ensemble algorithm to generate an average importance score for each feature based on the assessment of six statistical and machine learning techniques. With all channels counted in, the top five most referred feature types are Hurst exponent, mean, the ratio of the major/minor axis standard deviation of the Poincaré plot of the signal, statistical complexity, and crest factor. The left rostral prefrontal cortex (RLPFC) was the most relevant sub-region. Significantly strong correlations were found between the hemodynamic features derived at this sub-region and all three stress indicators. The dorsolateral prefrontal cortex (DLPFC) is also a relevant cortical area. The areas of mid-DLPFC and caudal-DLPFC both demonstrated significant and moderate association to all three stress indicators. No relevance was found in the ventrolateral prefrontal cortex. The preliminary results shed light on the possible role of the RLPCF, especially the left RLPCF, in processing stress during sleep. In addition, our findings echoed the previous stress studies conducted during wake time and provides supplementary evidence on the relevance of the dorsolateral prefrontal cortex in stress responses during sleep. This pilot study serves as a proof-of-concept for a new research paradigm to stress research and identified exciting opportunities for future studies.
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Lee YJ, Huang SY, Lin CP, Tsai SJ, Yang AC. Alteration of power law scaling of spontaneous brain activity in schizophrenia. Schizophr Res 2021; 238:10-19. [PMID: 34562833 DOI: 10.1016/j.schres.2021.08.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/04/2021] [Accepted: 08/23/2021] [Indexed: 10/20/2022]
Abstract
Nonlinear dynamical analysis has been used to quantify the complexity of brain signal at temporal scales. Power law scaling is a well-validated method in physics that has been used to describe the dynamics of a system in the frequency domain, ranging from noisy oscillation to complex fluctuations. In this research, we investigated the power-law characteristics in a large-scale resting-state fMRI data of schizophrenia and healthy participants derived from Taiwan Aging and Mental Illness cohort. We extracted the power spectral density (PSD) of resting signal by Fourier transform. Power law scaling of PSD was estimated by determining the slope of the regression line fitting to the logarithm of PSD. t-Test was used to assess the statistical difference in power law scaling between schizophrenia and healthy participants. The significant differences in power law scaling were found in six brain regions. Schizophrenia patients have significantly more positive power law scaling (i.e., more homogenous frequency components) at four brain regions: left precuneus, left medial dorsal nucleus, right inferior frontal gyrus, and right middle temporal gyrus and less positive power law scaling (i.e., more dominant at lower frequency range) in bilateral putamen compared with healthy participants. Moreover, significant correlations of power law scaling with the severity of psychosis were found. These findings suggest that schizophrenia has abnormal brain signal complexity linked to psychotic symptoms. The power law scaling represents the dynamical properties of resting-state fMRI signal may serve as a novel functional brain imaging marker for evaluating patients with mental illness.
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Affiliation(s)
- Yi-Ju Lee
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan; Laboratory of Precision Psychiatry, Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Institute of Statistical Science, Academia Sinica, Taipei, Taiwan
| | - Su-Yun Huang
- Institute of Statistical Science, Academia Sinica, Taipei, Taiwan
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Jen Tsai
- Laboratory of Precision Psychiatry, Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Brain Science and Digital Medicine Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Albert C Yang
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Yang Ming Chiao Tung University and Academia Sinica, Taipei, Taiwan; Laboratory of Precision Psychiatry, Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan; Institute of Brain Science and Digital Medicine Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.
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32
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Entropy as Measure of Brain Networks’ Complexity in Eyes Open and Closed Conditions. Symmetry (Basel) 2021. [DOI: 10.3390/sym13112178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Brain complexity can be revealed even through a comparison between two trivial conditions, such as eyes open and eyes closed (EO and EC respectively) during resting. Electroencephalogram (EEG) has been widely used to investigate brain networks, and several non-linear approaches have been applied to investigate EO and EC signals modulation, both symmetric and not. Entropy is one of the approaches used to evaluate the system disorder. This study explores the differences in the EO and EC awake brain dynamics by measuring entropy. In particular, an approximate entropy (ApEn) was measured, focusing on the specific cerebral areas (frontal, central, parietal, occipital, temporal) on EEG data of 37 adult healthy subjects while resting. Each participant was submitted to an EO and an EC resting EEG recording in two separate sessions. The results showed that in the EO condition the cerebral networks of the subjects are characterized by higher values of entropy than in the EC condition. All the cerebral regions are subjected to this chaotic behavior, symmetrically in both hemispheres, proving the complexity of networks dynamics dependence from the subject brain state. Remarkable dynamics regarding cerebral networks during simple resting and awake brain states are shown by entropy. The application of this parameter can be also extended to neurological conditions, to establish and monitor personalized rehabilitation treatments.
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33
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Ortiz A, Bradler K, Mowete M, MacLean S, Garnham J, Slaney C, Mulsant BH, Alda M. The futility of long-term predictions in bipolar disorder: mood fluctuations are the result of deterministic chaotic processes. Int J Bipolar Disord 2021; 9:30. [PMID: 34596784 PMCID: PMC8486895 DOI: 10.1186/s40345-021-00235-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/17/2021] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Understanding the underlying architecture of mood regulation in bipolar disorder (BD) is important, as we are starting to conceptualize BD as a more complex disorder than one of recurring manic or depressive episodes. Nonlinear techniques are employed to understand and model the behavior of complex systems. Our aim was to assess the underlying nonlinear properties that account for mood and energy fluctuations in patients with BD; and to compare whether these processes were different in healthy controls (HC) and unaffected first-degree relatives (FDR). We used three different nonlinear techniques: Lyapunov exponent, detrended fluctuation analysis and fractal dimension to assess the underlying behavior of mood and energy fluctuations in all groups; and subsequently to assess whether these arise from different processes in each of these groups. RESULTS There was a positive, short-term autocorrelation for both mood and energy series in all three groups. In the mood series, the largest Lyapunov exponent was found in HC (1.84), compared to BD (1.63) and FDR (1.71) groups [F (2, 87) = 8.42, p < 0.005]. A post-hoc Tukey test showed that Lyapunov exponent in HC was significantly higher than both the BD (p = 0.003) and FDR groups (p = 0.03). Similarly, in the energy series, the largest Lyapunov exponent was found in HC (1.85), compared to BD (1.76) and FDR (1.67) [F (2, 87) = 11.02; p < 0.005]. There were no significant differences between groups for the detrended fluctuation analysis or fractal dimension. CONCLUSIONS The underlying nature of mood variability is in keeping with that of a chaotic system, which means that fluctuations are generated by deterministic nonlinear process(es) in HC, BD, and FDR. The value of this complex modeling lies in analyzing the nature of the processes involved in mood regulation. It also suggests that the window for episode prediction in BD will be inevitably short.
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Affiliation(s)
- Abigail Ortiz
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
- Centre for Addiction & Mental Health, CAMH 100 Stokes St., Rm 4229, Toronto, ON, M6J 1H4, Canada.
| | | | - Maxine Mowete
- Department of Electrical Engineering, University of Ottawa, Ottawa, ON, Canada
| | - Stephane MacLean
- Institute for Mental Health Research, The Royal Ottawa Hospital, Ottawa, ON, Canada
| | | | | | - Benoit H Mulsant
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Centre for Addiction & Mental Health, CAMH 100 Stokes St., Rm 4229, Toronto, ON, M6J 1H4, Canada
| | - Martin Alda
- Department of Psychiatry, Dalhousie University, Halifax, NS, Canada
- National Institute of Mental Health, Klecany, Czech Republic
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Real-time non-uniform EEG sampling. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Rué-Queralt J, Stevner A, Tagliazucchi E, Laufs H, Kringelbach ML, Deco G, Atasoy S. Decoding brain states on the intrinsic manifold of human brain dynamics across wakefulness and sleep. Commun Biol 2021; 4:854. [PMID: 34244598 PMCID: PMC8270946 DOI: 10.1038/s42003-021-02369-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 06/18/2021] [Indexed: 02/06/2023] Open
Abstract
Current state-of-the-art functional magnetic resonance imaging (fMRI) offers remarkable imaging quality and resolution, yet, the intrinsic dimensionality of brain dynamics in different states (wakefulness, light and deep sleep) remains unknown. Here we present a method to reveal the low dimensional intrinsic manifold underlying human brain dynamics, which is invariant of the high dimensional spatio-temporal representation of the neuroimaging technology. By applying this intrinsic manifold framework to fMRI data acquired in wakefulness and sleep, we reveal the nonlinear differences between wakefulness and three different sleep stages, and successfully decode these different brain states with a mean accuracy across participants of 96%. Remarkably, a further group analysis shows that the intrinsic manifolds of all participants share a common topology. Overall, our results reveal the intrinsic manifold underlying the spatiotemporal dynamics of brain activity and demonstrate how this manifold enables the decoding of different brain states such as wakefulness and various sleep stages.
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Affiliation(s)
- Joan Rué-Queralt
- grid.5612.00000 0001 2172 2676Center of Brain and Cognition, Universitat Pompeu Fabra, Barcelona, Spain
| | - Angus Stevner
- grid.4991.50000 0004 1936 8948Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK ,grid.7048.b0000 0001 1956 2722Center for Music in the Brain, Aarhus University, Aarhus, Denmark
| | - Enzo Tagliazucchi
- grid.7345.50000 0001 0056 1981Instituto de Física de Buenos Aires and Physics Deparment (University of Buenos Aires), Buenos Aires, Argentina
| | - Helmut Laufs
- grid.7839.50000 0004 1936 9721Department of Neurology and Brain Imaging Center, Goethe University, Frankfurt am Main, Germany ,grid.9764.c0000 0001 2153 9986Department of Neurology, University Hospital Schleswig-Holstein, Christian-Albrechts-University, Kiel, Germany
| | - Morten L. Kringelbach
- grid.4991.50000 0004 1936 8948Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK ,grid.7048.b0000 0001 1956 2722Center for Music in the Brain, Aarhus University, Aarhus, Denmark
| | - Gustavo Deco
- grid.5612.00000 0001 2172 2676Center of Brain and Cognition, Universitat Pompeu Fabra, Barcelona, Spain ,grid.425902.80000 0000 9601 989XInstitució Catalana de Recerca i Estudis Avancats (ICREA), Barcelona, Spain ,grid.419524.f0000 0001 0041 5028Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany ,grid.1002.30000 0004 1936 7857School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Selen Atasoy
- grid.4991.50000 0004 1936 8948Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK ,grid.7048.b0000 0001 1956 2722Center for Music in the Brain, Aarhus University, Aarhus, Denmark
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Zhou GL, Pan Y, Liao YY, Liang JX, Zhang XM, Luo YX. Short-Term Impact of Sleep Apnea/Hypopnea on the Interaction Between Various Cortical Areas. Clin EEG Neurosci 2021; 52:296-306. [PMID: 34003701 DOI: 10.1177/1550059420965441] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Sleep apnea/hypopnea syndrome (SAHS) can change brain structure and function. These alterations are related to respiratory event-induced abnormal sleep, however, how brain activity changes during these events is less well understood. METHODS To study information content and interaction among various cortical regions, we analyzed the variations of permutation entropy (PeEn) and symbolic transfer entropy (STE) of electroencephalography (EEG) activity during respiratory events. In this study, 57 patients with moderate SAHS were enrolled, including 2804 respiratory events. The events terminated with cortical arousal were independently researched. RESULTS PeEn and STE were lower during apnea/hypopnea, and most of the brain interaction was higher after apnea/hypopnea termination than that before apnea in N2 stage. As indicated by STE, the respiratory events also affected the stability of information transmission mode. In N1, N2, and rapid eye movement (REM) stages, the information flow direction was posterior-to-anterior, but the anterior-to-posterior increased relatively during apnea/hypopnea. The above EEG activity trends maintained in events with cortical arousal. CONCLUSIONS These results may be related to the intermittent hypoxia during apnea and the cortical response. Furthermore, increased frontal information outflow, which was related to the compensatory activation of frontal neurons, may associate with cognitive function.
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Affiliation(s)
- Guo-Lin Zhou
- School of Biomedical Engineering, 26469Sun Yat-Sen University, Guangzhou, China
| | - Yu Pan
- School of Biomedical Engineering, 26469Sun Yat-Sen University, Guangzhou, China
| | - Yuan-Yuan Liao
- School of Biomedical Engineering, 26469Sun Yat-Sen University, Guangzhou, China
| | - Jiu-Xing Liang
- Institute for Brain Research and Rehabilitation, Guangdong Key Laboratory of Mental Health and Cognitive Science, Center for Studies of Psychological Application, 12451South China Normal University, Guangzhou, China
| | - Xiang-Min Zhang
- 373651Sleep-Disordered Breathing Center of the 6th Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Yu-Xi Luo
- School of Biomedical Engineering, 26469Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Sensor Technology and Biomedical Instrument, Sun Yat-Sen University, Guangzhou, China
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Stancin I, Cifrek M, Jovic A. A Review of EEG Signal Features and their Application in Driver Drowsiness Detection Systems. SENSORS 2021; 21:s21113786. [PMID: 34070732 PMCID: PMC8198610 DOI: 10.3390/s21113786] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/26/2021] [Accepted: 05/28/2021] [Indexed: 01/05/2023]
Abstract
Detecting drowsiness in drivers, especially multi-level drowsiness, is a difficult problem that is often approached using neurophysiological signals as the basis for building a reliable system. In this context, electroencephalogram (EEG) signals are the most important source of data to achieve successful detection. In this paper, we first review EEG signal features used in the literature for a variety of tasks, then we focus on reviewing the applications of EEG features and deep learning approaches in driver drowsiness detection, and finally we discuss the open challenges and opportunities in improving driver drowsiness detection based on EEG. We show that the number of studies on driver drowsiness detection systems has increased in recent years and that future systems need to consider the wide variety of EEG signal features and deep learning approaches to increase the accuracy of detection.
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Sun J, Hu X, Peng S, Peng CK, Ma Y. Automatic classification of excitation location of snoring sounds. J Clin Sleep Med 2021; 17:1031-1038. [PMID: 33560203 DOI: 10.5664/jcsm.9094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
STUDY OBJECTIVES For surgical treatment of patients with obstructive sleep apnea-hypopnea syndrome, it is crucial to locate accurately the obstructive sites in the upper airway; however, noninvasive methods for locating the obstructive sites have not been well explored. Snoring, as the cardinal symptom of obstructive sleep apnea-hypopnea syndrome, should contain information that reflects the state of the upper airway. Through the classification of snores produced at four different locations, this study aimed to test the hypothesis that snores generated by various obstructive sites differ. METHODS We trained and tested our model on a public data set that comprised 219 participants. For each snore episode, an acoustic and a physiological feature were extracted and concatenated, forming a 59-dimensional fusion feature. A principal component analysis and a support machine vector were used for dimensional reduction and snore classification. The performance of the proposed model was evaluated using several metrics: sensitivity, precision, specificity, area under the receiver operating characteristic curve, and F1 score. RESULTS The unweighted average values of sensitivity, precision, specificity, area under the curve, and F1 were 86.36%, 89.09%, 96.4%, 87.9%, and 87.63%, respectively. The model achieved 98.04%, 80.56%, 72.73%, and 94.12% sensitivity for types V (velum), O (oropharyngeal), T (tongue), and E (epiglottis) snores. CONCLUSIONS The characteristics of snores are related to the state of the upper airway. The machine-learning-based model can be used to locate the vibration sites in the upper airway.
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Affiliation(s)
- Jingpeng Sun
- Institute of Automation, Chinese Academy of Sciences, Beijing, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, People's Republic of China.,Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Xiyuan Hu
- School of Computer Science and Engineering, Nanjing University of Science and Technology, Nanjing, People's Republic of China
| | - Silong Peng
- Institute of Automation, Chinese Academy of Sciences, Beijing, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Chung-Kang Peng
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Yan Ma
- Division of Interdisciplinary Medicine and Biotechnology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
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Hou F, Zhang L, Qin B, Gaggioni G, Liu X, Vandewalle G. Changes in EEG permutation entropy in the evening and in the transition from wake to sleep. Sleep 2021; 44:5959865. [PMID: 33159205 DOI: 10.1093/sleep/zsaa226] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/30/2020] [Indexed: 02/02/2023] Open
Abstract
Quantifying the complexity of the EEG signal during prolonged wakefulness and during sleep is gaining interest as an additional mean to characterize the mechanisms associated with sleep and wakefulness regulation. Here, we characterized how EEG complexity, as indexed by Multiscale Permutation Entropy (MSPE), changed progressively in the evening prior to light off and during the transition from wakefulness to sleep. We further explored whether MSPE was able to discriminate between wakefulness and sleep around sleep onset and whether MSPE changes were correlated with spectral measures of the EEG related to sleep need during concomitant wakefulness (theta power-Ptheta: 4-8 Hz). To address these questions, we took advantage of large datasets of several hundred of ambulatory EEG recordings of individual of both sexes aged 25-101 years. Results show that MSPE significantly decreases before light off (i.e. before sleep time) and in the transition from wakefulness to sleep onset. Furthermore, MSPE allows for an excellent discrimination between pre-sleep wakefulness and early sleep. Finally, we show that MSPE is correlated with concomitant Ptheta. Yet, the direction of the latter correlation changed from before light-off to the transition to sleep. Given the association between EEG complexity and consciousness, MSPE may track efficiently putative changes in consciousness preceding sleep onset. An MSPE stands as a comprehensive measure that is not limited to a given frequency band and reflects a progressive change brain state associated with sleep and wakefulness regulation. It may be an effective mean to detect when the brain is in a state close to sleep onset.
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Affiliation(s)
- Fengzhen Hou
- School of Science, China Pharmaceutical University, Nanjing, China
| | - Lulu Zhang
- School of Science, China Pharmaceutical University, Nanjing, China
| | - Baokun Qin
- School of Computer, Chongqing University, Chongqing, China
| | - Giulia Gaggioni
- GIGA-Cyclotron Research Centre-In Vivo Imaging, University of Liège, Liège, Belgium
| | - Xinyu Liu
- School of Science, China Pharmaceutical University, Nanjing, China
| | - Gilles Vandewalle
- GIGA-Cyclotron Research Centre-In Vivo Imaging, University of Liège, Liège, Belgium
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40
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Aamodt A, Nilsen AS, Thürer B, Moghadam FH, Kauppi N, Juel BE, Storm JF. EEG Signal Diversity Varies With Sleep Stage and Aspects of Dream Experience. Front Psychol 2021; 12:655884. [PMID: 33967919 PMCID: PMC8102678 DOI: 10.3389/fpsyg.2021.655884] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/18/2021] [Indexed: 11/13/2022] Open
Abstract
Several theories link consciousness to complex cortical dynamics, as suggested by comparison of brain signal diversity between conscious states and states where consciousness is lost or reduced. In particular, Lempel-Ziv complexity, amplitude coalition entropy and synchrony coalition entropy distinguish wakefulness and REM sleep from deep sleep and anesthesia, and are elevated in psychedelic states, reported to increase the range and vividness of conscious contents. Some studies have even found correlations between complexity measures and facets of self-reported experience. As suggested by integrated information theory and the entropic brain hypothesis, measures of differentiation and signal diversity may therefore be measurable correlates of consciousness and phenomenological richness. Inspired by these ideas, we tested three hypotheses about EEG signal diversity related to sleep and dreaming. First, diversity should decrease with successively deeper stages of non-REM sleep. Second, signal diversity within the same sleep stage should be higher for periods of dreaming vs. non-dreaming. Third, specific aspects of dream contents should correlate with signal diversity in corresponding cortical regions. We employed a repeated awakening paradigm in sleep deprived healthy volunteers, with immediate dream report and rating of dream content along a thought-perceptual axis, from exclusively thought-like to exclusively perceptual. Generalized linear mixed models were used to assess how signal diversity varied with sleep stage, dreaming and thought-perceptual rating. Signal diversity decreased with sleep depth, but was not significantly different between dreaming and non-dreaming, even though there was a significant positive correlation between Lempel-Ziv complexity of EEG recorded over the posterior cortex and thought-perceptual ratings of dream contents.
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Affiliation(s)
- Arnfinn Aamodt
- Brain Signalling Lab, Division of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - André Sevenius Nilsen
- Brain Signalling Lab, Division of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Benjamin Thürer
- Brain Signalling Lab, Division of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Fatemeh Hasanzadeh Moghadam
- Brain Signalling Lab, Division of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Nils Kauppi
- Brain Signalling Lab, Division of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Bjørn Erik Juel
- Brain Signalling Lab, Division of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Johan Frederik Storm
- Brain Signalling Lab, Division of Physiology, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
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Alù F, Orticoni A, Judica E, Cotelli M, Rossini PM, Miraglia F, Vecchio F. Entropy modulation of electroencephalographic signals in physiological aging. Mech Ageing Dev 2021; 196:111472. [PMID: 33766746 DOI: 10.1016/j.mad.2021.111472] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 01/22/2023]
Abstract
Aging is a multifactorial physiological process characterized by the accumulation of degenerative processes impacting on different brain functions, including the cognitive one. A tool largely employed in the investigation of brain networks is the electroencephalogram (EEG). Given the cerebral complexity and dynamism, many non-linear approaches have been applied to explore age-related brain electrical activity modulation detected by the EEG: one of them is the entropy, which measures the disorder of a system. The present study had the aim to investigate aging influence on brain dynamics applying Approximate Entropy (ApEn) parameter to resting state EEG data of 68 healthy adult participants, divided with respect to their age in two groups, focusing on several specialized brain regions. Results showed that elderly participants present higher ApEn values than younger participants in the central, parietal and occipital areas, confirming the hypothesis that aging is characterized by an evolution of brain dynamics. Such findings may reflect a reduced synchronization of the neural networks cyclic activity, due to the reduction of cerebral connections typically found in aging process. Understanding the dynamics of brain networks by applying the entropy parameter could be useful for developing appropriate and personalized rehabilitation programs and for future studies on neurodegenerative diseases.
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Affiliation(s)
- Francesca Alù
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy
| | - Alessandro Orticoni
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy
| | - Elda Judica
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milano, Italy
| | - Maria Cotelli
- Neuropsychology Unit, IRCCS Istituto Centro San Giovanni di DioFatebenefratelli, Brescia, Italy
| | - Paolo Maria Rossini
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy
| | - Francesca Miraglia
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy
| | - Fabrizio Vecchio
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy.
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Hao Z, Yang Y, Hua A, Gao Y, Wang J. Age-Related Changes in Standing Balance in Preschoolers Using Traditional and Nonlinear Methods. Front Physiol 2021; 12:625553. [PMID: 33692702 PMCID: PMC7937647 DOI: 10.3389/fphys.2021.625553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/28/2021] [Indexed: 11/13/2022] Open
Abstract
Considerable disagreement exists on the linearity of the development of standing balance in children. This study aimed to use different traditional and nonlinear methods to investigate age-related changes in standing balance in preschoolers. A sample of 118 preschoolers took part in this study. A force platform was used to record the center of pressure during standing balance over 15 s in three conditions: eyes open, eyes closed, and/or head extended backward. Detrended fluctuation analysis (DFA), recurrence quantification analysis (RQA), and traditional measures were used to evaluate standing balance. The main results are as follows: (1) Higher range and SD in the anterior-posterior (AP) direction were observed for 5-year-old than for 4-year-old children, while higher DFA coefficient (at shorter time scales) and higher determinism and laminarity in the AP direction were found for 5-year-old children compared to 3- and 4-year-old children; and (2) as sensory conditions became more challenging, all traditional measures increased and DFA coefficients (at shorter and longer time scales) decreased in the AP and mediolateral directions, while determinism and laminarity significantly declined in the AP direction. In conclusion, although increased postural sway, 5-year-old preschool children's balance performance improved, and their control strategy changed significantly compared with the younger preschoolers. Sensory perturbation (eye closure and/or head extension) changed preschoolers' balance performance and control strategy. Moreover, both traditional and nonlinear methods provided complementary information on the control of standing balance in preschoolers.
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Affiliation(s)
- Zengming Hao
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China
| | - Yi Yang
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China
| | - Anke Hua
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China
| | - Ying Gao
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China
| | - Jian Wang
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China.,Center for Psychological Sciences, Zhejiang University, Hangzhou, China
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An Electroencephalogram Metric of Temporal Complexity Tracks Psychometric Impairment Caused by Low-dose Nitrous Oxide. Anesthesiology 2021; 134:202-218. [PMID: 33433619 DOI: 10.1097/aln.0000000000003628] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Nitrous oxide produces non-γ-aminobutyric acid sedation and psychometric impairment and can be used as scientific model for understanding mechanisms of progressive cognitive disturbances. Temporal complexity of the electroencephalogram may be a sensitive indicator of these effects. This study measured psychometric performance and the temporal complexity of the electroencephalogram in participants breathing low-dose nitrous oxide. METHODS In random order, 20, 30, and 40% end-tidal nitrous oxide was administered to 12 participants while recording 32-channel electroencephalogram and psychometric function. A novel metric quantifying the spatial distribution of temporal electroencephalogram complexity, comprised of (1) absolute cross-correlation calculated between consecutive 0.25-s time samples; 2) binarizing these cross-correlation matrices using the median of all channels as threshold; (3) using quantitative recurrence analysis, the complexity in temporal changes calculated by the Shannon entropy of the probability distribution of the diagonal line lengths; and (4) overall spatial extent and intensity of brain complexity, was quantified by calculating median temporal complexity of channels whose complexities were above 1 at baseline. This region approximately overlay the brain's default mode network, so this summary statistic was termed "default-mode-network complexity." RESULTS Nitrous oxide concentration correlated with psychometric impairment (r = 0.50, P < 0.001). Baseline regional electroencephalogram complexity at midline was greater than in lateral temporal channels (1.33 ± 0.14 bits vs. 0.81 ± 0.12 bits, P < 0.001). A dose of 40% N2O decreased midline (mean difference [95% CI], 0.20 bits [0.09 to 0.31], P = 0.002) and prefrontal electroencephalogram complexity (mean difference [95% CI], 0.17 bits [0.08 to 0.27], P = 0.002). The lateral temporal region did not change significantly (mean difference [95% CI], 0.14 bits [-0.03 to 0.30], P = 0.100). Default-mode-network complexity correlated with N2O concentration (r = -0.55, P < 0.001). A default-mode-network complexity mixed-effects model correlated with psychometric impairment (r2 = 0.67; receiver operating characteristic area [95% CI], 0.72 [0.59 to 0.85], P < 0.001). CONCLUSIONS Temporal complexity decreased most markedly in medial cortical regions during low-dose nitrous oxide exposures, and this change tracked psychometric impairment. EDITOR’S PERSPECTIVE
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Mohammadi Y, Moradi MH. Prediction of Depression Severity Scores Based on Functional Connectivity and Complexity of the EEG Signal. Clin EEG Neurosci 2021; 52:52-60. [PMID: 33040603 DOI: 10.1177/1550059420965431] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Depression is one of the most common mental disorders and the leading cause of functional disabilities. This study aims to specify whether functional connectivity and complexity of brain activity can predict the severity of depression (Beck Depression Inventory-II scores). METHODS Resting-state, eyes-closed EEG data were recorded from 60 depressed patients. A phase synchronization measure was used to estimate functional connectivity between all pairs of the EEG channels in the delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) frequency bands. To quantify the local value of functional connectivity, 2 graph theory metrics, degree, and clustering coefficient (CC), were measured. Moreover, Lempel-Ziv complexity (LZC) and fuzzy entropy (FuzzyEn) were used to measure the complexity of the EEG signal. RESULTS Through correlation analysis, a significant negative relationship was found between graph metrics and depression severity in the alpha band. This association was strongly positive for the complexity measures in alpha and delta bands. Also, the linear regression model represented a substantial performance of depression severity prediction based on EEG features of the alpha band (r = 0.839; P < .0001, root mean square error score of 7.69). CONCLUSION We found that the brain activity of patients with depression was related to depression severity. Abnormal brain activity reflects an increase in the severity of depression. The presented regression model provides a quantitative depression severity prediction, which can inform the development of EEG state and exhibit potential desirable application for the medical treatment of the depressive disorder.
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Affiliation(s)
- Yousef Mohammadi
- Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Islamic Republic of Iran
| | - Mohammad Hassan Moradi
- Biomedical Engineering Department, Amirkabir University of Technology, Tehran, Islamic Republic of Iran
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Zhou Y, Huang S, Xu Z, Wang P, Wu X, Zhang D. Cognitive Workload Recognition Using EEG Signals and Machine Learning: A Review. IEEE Trans Cogn Dev Syst 2021. [DOI: 10.1109/tcds.2021.3090217] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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46
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Ladeira G, Marwan N, Destro-Filho JB, Davi Ramos C, Lima G. Frequency spectrum recurrence analysis. Sci Rep 2020; 10:21241. [PMID: 33277526 PMCID: PMC7718872 DOI: 10.1038/s41598-020-77903-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 11/02/2020] [Indexed: 11/09/2022] Open
Abstract
In this paper, we present the new frequency spectrum recurrence analysis technique by means of electro-encephalon signals (EES) analyses. The technique is suitable for time series analysis with noise and disturbances. EES were collected, and alpha waves of the occipital region were analysed by comparing the signals from participants in two states, eyes open and eyes closed. Firstly, EES were characterized and analysed by means of techniques already known to compare with the results of the innovative technique that we present here. We verified that, standard recurrence quantification analysis by means of EES time series cannot statistically distinguish the two states. However, the new frequency spectrum recurrence quantification exhibit quantitatively whether the participants have their eyes open or closed. In sequence, new quantifiers are created for analysing the recurrence concentration on frequency bands. These analyses show that EES with similar frequency spectrum have different recurrence levels revealing different behaviours of the nervous system. The technique can be used to deepen the study on depression, stress, concentration level and other neurological issues and also can be used in any complex system.
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Affiliation(s)
- Guênia Ladeira
- Faculty of Mechanical Engineering, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil.
| | - Norbert Marwan
- Potsdam Institute for Climate Impact Research, P.O. Box 601203, 14412, Potsdam, Germany.,Interdisciplinary Centre for Dynamics of Complex Systems, University of Potsdam, 14415, Potsdam, Germany
| | - João-Batista Destro-Filho
- Faculty of Electrical Engineering, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Camila Davi Ramos
- Faculty of Electrical Engineering, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
| | - Gabriela Lima
- Faculty of Electrical Engineering, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil
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Mullins AE, Kam K, Parekh A, Bubu OM, Osorio RS, Varga AW. Obstructive Sleep Apnea and Its Treatment in Aging: Effects on Alzheimer's disease Biomarkers, Cognition, Brain Structure and Neurophysiology. Neurobiol Dis 2020; 145:105054. [PMID: 32860945 PMCID: PMC7572873 DOI: 10.1016/j.nbd.2020.105054] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 08/13/2020] [Accepted: 08/18/2020] [Indexed: 02/08/2023] Open
Abstract
Here we review the impact of obstructive sleep apnea (OSA) on biomarkers of Alzheimer's disease (AD) pathogenesis, neuroanatomy, cognition and neurophysiology, and present the research investigating the effects of continuous positive airway pressure (CPAP) therapy. OSA is associated with an increase in AD markers amyloid-β and tau measured in cerebrospinal fluid (CSF), by Positron Emission Tomography (PET) and in blood serum. There is some evidence suggesting CPAP therapy normalizes AD biomarkers in CSF but since mechanisms for amyloid-β and tau production/clearance in humans are not completely understood, these findings remain preliminary. Deficits in the cognitive domains of attention, vigilance, memory and executive functioning are observed in OSA patients with the magnitude of impairment appearing stronger in younger people from clinical settings than in older community samples. Cognition improves with varying degrees after CPAP use, with the greatest effect seen for attention in middle age adults with more severe OSA and sleepiness. Paradigms in which encoding and retrieval of information are separated by periods of sleep with or without OSA have been done only rarely, but perhaps offer a better chance to understand cognitive effects of OSA than isolated daytime testing. In cognitively normal individuals, changes in EEG microstructure during sleep, particularly slow oscillations and spindles, are associated with biomarkers of AD, and measures of cognition and memory. Similar changes in EEG activity are reported in AD and OSA, such as "EEG slowing" during wake and REM sleep, and a degradation of NREM EEG microstructure. There is evidence that CPAP therapy partially reverses these changes but large longitudinal studies demonstrating this are lacking. A diagnostic definition of OSA relying solely on the Apnea Hypopnea Index (AHI) does not assist in understanding the high degree of inter-individual variation in daytime impairments related to OSA or response to CPAP therapy. We conclude by discussing conceptual challenges to a clinical trial of OSA treatment for AD prevention, including inclusion criteria for age, OSA severity, and associated symptoms, the need for a potentially long trial, defining relevant primary outcomes, and which treatments to target to optimize treatment adherence.
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Affiliation(s)
- Anna E Mullins
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Korey Kam
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ankit Parekh
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Omonigho M Bubu
- Center for Brain Health, Department of Psychiatry, NYU Langone Medical Center, New York, NY 10016, USA
| | - Ricardo S Osorio
- Center for Brain Health, Department of Psychiatry, NYU Langone Medical Center, New York, NY 10016, USA
| | - Andrew W Varga
- Mount Sinai Integrative Sleep Center, Division of Pulmonary, Critical Care, and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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48
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Moradi F, Mohammadi H, Rezaei M, Sariaslani P, Razazian N, Khazaie H, Adeli H. A Novel Method for Sleep-Stage Classification Based on Sonification of Sleep Electroencephalogram Signals Using Wavelet Transform and Recurrent Neural Network. Eur Neurol 2020; 83:468-486. [PMID: 33120386 DOI: 10.1159/000511306] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 09/02/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Visual sleep-stage scoring is a time-consuming technique that cannot extract the nonlinear characteristics of electroencephalogram (EEG). This article presents a novel method for sleep-stage differentiation based on sonification of sleep-EEG signals using wavelet transform and recurrent neural network (RNN). METHODS Two RNNs were designed and trained separately based on a database of classical guitar pieces and Kurdish tanbur Makams using a long short-term memory model. Moreover, discrete wavelet transform and wavelet packet decomposition were used to determine the association between the EEG signals and musical pitches. Continuous wavelet transform was applied to extract musical beat-based features from the EEG. Then, the pretrained RNN was used to generate music. To test the proposed model, 11 sleep EEGs were mapped onto the guitar and tanbur frequency intervals and presented to the pretrained RNN. Next, the generated music was randomly presented to 2 neurologists. RESULTS The proposed model classified the sleep stages with an accuracy of >81% for tanbur and more than 93% for guitar musical pieces. The inter-rater reliability measured by Cohen's kappa coefficient (κ) revealed good reliability for both tanbur (κ = 0.64, p < 0.001) and guitar musical pieces (κ = 0.85, p < 0.001). CONCLUSION The present EEG sonification method leads to valid sleep staging by clinicians. The method could be used on various EEG databases for classification, differentiation, diagnosis, and treatment purposes. Real-time EEG sonification can be used as a feedback tool for replanning of neurophysiological functions for the management of many neurological and psychiatric disorders in the future.
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Affiliation(s)
- Foad Moradi
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.,Electrical and Computer Engineering Faculty, Semnan University, Semnan, Iran.,Department of Neurology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Hiwa Mohammadi
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran, .,Department of Neurology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran, .,Clinical Research Development Center, Imam Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran,
| | - Mohammad Rezaei
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.,Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Payam Sariaslani
- Department of Neurology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.,Clinical Research Development Center, Imam Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Nazanin Razazian
- Department of Neurology, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran.,Clinical Research Development Center, Imam Reza Hospital, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Habibolah Khazaie
- Sleep Disorders Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Hojjat Adeli
- Department of Biomedical Informatics and Department of Neuroscience, The Ohio State University, Columbus, Ohio, USA
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49
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Approximate Entropy of Brain Network in the Study of Hemispheric Differences. ENTROPY 2020; 22:e22111220. [PMID: 33286988 PMCID: PMC7711834 DOI: 10.3390/e22111220] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 12/23/2022]
Abstract
Human brain, a dynamic complex system, can be studied with different approaches, including linear and nonlinear ones. One of the nonlinear approaches widely used in electroencephalographic (EEG) analyses is the entropy, the measurement of disorder in a system. The present study investigates brain networks applying approximate entropy (ApEn) measure for assessing the hemispheric EEG differences; reproducibility and stability of ApEn data across separate recording sessions were evaluated. Twenty healthy adult volunteers were submitted to eyes-closed resting EEG recordings, for 80 recordings. Significant differences in the occipital region, with higher values of entropy in the left hemisphere than in the right one, show that the hemispheres become active with different intensities according to the performed function. Besides, the present methodology proved to be reproducible and stable, when carried out on relatively brief EEG epochs but also at a 1-week distance in a group of 36 subjects. Nonlinear approaches represent an interesting probe to study the dynamics of brain networks. ApEn technique might provide more insight into the pathophysiological processes underlying age-related brain disconnection as well as for monitoring the impact of pharmacological and rehabilitation treatments.
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50
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Liu Y, Lin Y, Jia Z, Ma Y, Wang J. Representation based on ordinal patterns for seizure detection in EEG signals. Comput Biol Med 2020; 126:104033. [PMID: 33091826 DOI: 10.1016/j.compbiomed.2020.104033] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 09/25/2020] [Accepted: 10/01/2020] [Indexed: 11/26/2022]
Abstract
EEG signals carry rich information about brain activity and play an important role in the diagnosis and recognition of epilepsy. Numerous algorithms using EEG signals to detect seizures have been developed in recent decades. However, most of them require well-designed features that highly depend on domain-specific knowledge and algorithm expertise. In this study, we introduce the unigram ordinal pattern (UniOP) and bigram ordinal pattern (BiOP) representations to capture the different underlying dynamics of time series, which only assumes that time series derived from different dynamics can be characterized by repeated ordinal patterns. Specifically, we first transform each subsequence in a time series into the corresponding ordinal pattern in terms of the ranking of values and consider the distribution of ordinal patterns of all subsequences as the UniOP representation. Furthermore, we consider the distribution of the cooccurrence of ordinal patterns as the BiOP representation to characterize the contextual information for each ordinal pattern. We then combine the proposed representations with the nearest neighbor algorithm to evaluate its effectiveness on three publicly available seizure datasets. The results on the Bonn EEG dataset demonstrate that this method provides more than 90% accuracy, sensitivity, and specificity in most cases and outperforms several state-of-the-art methods, which proves its ability to capture the key information of the underlying dynamics of EEG time series at healthy, seizure-free, and seizure states. The results on the second dataset are comparable with the state-of-the-art method, showing the good generalization ability of the proposed method. All performance metrics on the third dataset are approximately 89%, which demonstrates that the proposed representations are suitable for large-scale datasets.
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Affiliation(s)
- Yunxiao Liu
- Beijing Key Lab of Traffic Data Analysis and Mining, School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, PR China; CAAC Key Laboratory of Intelligent Passenger Service of Civil Aviation, Beijing, China
| | - Youfang Lin
- Beijing Key Lab of Traffic Data Analysis and Mining, School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, PR China; CAAC Key Laboratory of Intelligent Passenger Service of Civil Aviation, Beijing, China
| | - Ziyu Jia
- Beijing Key Lab of Traffic Data Analysis and Mining, School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, PR China; CAAC Key Laboratory of Intelligent Passenger Service of Civil Aviation, Beijing, China
| | - Yan Ma
- Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jing Wang
- Beijing Key Lab of Traffic Data Analysis and Mining, School of Computer and Information Technology, Beijing Jiaotong University, Beijing, 100044, PR China; CAAC Key Laboratory of Intelligent Passenger Service of Civil Aviation, Beijing, China.
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