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Tsai WX, Tsai SJ, Lin CP, Huang NE, Yang AC. Exploring timescale-specific functional brain networks and their associations with aging and cognitive performance in a healthy cohort without dementia. Neuroimage 2024; 289:120540. [PMID: 38355076 DOI: 10.1016/j.neuroimage.2024.120540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 02/02/2024] [Accepted: 02/12/2024] [Indexed: 02/16/2024] Open
Abstract
INTRODUCTION Functional brain networks (FBNs) coordinate brain functions and are studied in fMRI using blood-oxygen-level-dependent (BOLD) signal correlations. Previous research links FBN changes to aging and cognitive decline, but various physiological factors influnce BOLD signals. Few studies have investigated the intrinsic components of the BOLD signal in different timescales using signal decomposition. This study aimed to explore differences between intrinsic FBNs and traditional BOLD-FBN, examining their associations with age and cognitive performance in a healthy cohort without dementia. MATERIALS AND METHODS A total of 396 healthy participants without dementia (men = 157; women = 239; age range = 20-85 years) were enrolled in this study. The BOLD signal was decomposed into several intrinsic signals with different timescales using ensemble empirical mode decomposition, and FBNs were constructed based on both the BOLD and intrinsic signals. Subsequently, network features-global efficiency and local efficiency values-were estimated to determine their relationship with age and cognitive performance. RESULTS The findings revealed that the global efficiency of traditional BOLD-FBN correlated significantly with age, with specific intrinsic FBNs contributing to these correlations. Moreover, local efficiency analysis demonstrated that intrinsic FBNs were more meaningful than traditional BOLD-FBN in identifying brain regions related to age and cognitive performance. CONCLUSIONS These results underscore the importance of exploring timescales of BOLD signals when constructing FBN and highlight the relevance of specific intrinsic FBNs to aging and cognitive performance. Consequently, this decomposition-based FBN-building approach may offer valuable insights for future fMRI studies.
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Affiliation(s)
- Wen-Xiang Tsai
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Shih-Jen Tsai
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, Taipei 11217, Taiwan
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Norden E Huang
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan
| | - Albert C Yang
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan; Digital Medicine and Smart Healthcare Research Center, National Yang Ming Chiao Tung University, Taipei 11221, Taiwan.
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Chang WS, Liang WK, Li DH, Muggleton NG, Balachandran P, Huang NE, Juan CH. The association between working memory precision and the nonlinear dynamics of frontal and parieto-occipital EEG activity. Sci Rep 2023; 13:14252. [PMID: 37653059 PMCID: PMC10471634 DOI: 10.1038/s41598-023-41358-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 08/24/2023] [Indexed: 09/02/2023] Open
Abstract
Electrophysiological working memory (WM) research shows brain areas communicate via macroscopic oscillations across frequency bands, generating nonlinear amplitude modulation (AM) in the signal. Traditionally, AM is expressed as the coupling strength between the signal and a prespecified modulator at a lower frequency. Therefore, the idea of AM and coupling cannot be studied separately. In this study, 33 participants completed a color recall task while their brain activity was recorded through EEG. The AM of the EEG data was extracted using the Holo-Hilbert spectral analysis (HHSA), an adaptive method based on the Hilbert-Huang transforms. The results showed that WM load modulated parieto-occipital alpha/beta power suppression. Furthermore, individuals with higher frontal theta power and lower parieto-occipital alpha/beta power exhibited superior WM precision. In addition, the AM of parieto-occipital alpha/beta power predicted WM precision after presenting a target-defining probe array. The phase-amplitude coupling (PAC) between the frontal theta phase and parieto-occipital alpha/beta AM increased with WM load while processing incoming stimuli, but the PAC itself did not predict the subsequent recall performance. These results suggest frontal and parieto-occipital regions communicate through theta-alpha/beta PAC. However, the overall recall precision depends on the alpha/beta AM following the onset of the retro cue.
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Affiliation(s)
- Wen-Sheng Chang
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Dong-Han Li
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Neil G Muggleton
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
- Institute of Cognitive Neuroscience, University College London, London, UK
- Department of Psychology, Goldsmiths, University of London, London, UK
| | - Prasad Balachandran
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Cheng Kung University and Academia Sinica, Taipei, Taiwan
| | - Norden E Huang
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
- Data Analysis and Application Laboratory, The First Institute of Oceanography, Qingdao, China
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan.
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan.
- Department of Psychology, Kaohsiung Medical University, Kaohsiung, Taiwan.
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Chu KT, Lei WC, Wu MH, Fuh JL, Wang SJ, French IT, Chang WS, Chang CF, Huang NE, Liang WK, Juan CH. A holo-spectral EEG analysis provides an early detection of cognitive decline and predicts the progression to Alzheimer's disease. Front Aging Neurosci 2023; 15:1195424. [PMID: 37674782 PMCID: PMC10477374 DOI: 10.3389/fnagi.2023.1195424] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/25/2023] [Indexed: 09/08/2023] Open
Abstract
Aims Our aim was to differentiate patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) from cognitively normal (CN) individuals and predict the progression from MCI to AD within a 3-year longitudinal follow-up. A newly developed Holo-Hilbert Spectral Analysis (HHSA) was applied to resting state EEG (rsEEG), and features were extracted and subjected to machine learning algorithms. Methods A total of 205 participants were recruited from three hospitals, with CN (n = 51, MMSE > 26), MCI (n = 42, CDR = 0.5, MMSE ≥ 25), AD1 (n = 61, CDR = 1, MMSE < 25), AD2 (n = 35, CDR = 2, MMSE < 16), and AD3 (n = 16, CDR = 3, MMSE < 16). rsEEG was also acquired from all subjects. Seventy-two MCI patients (CDR = 0.5) were longitudinally followed up with two rsEEG recordings within 3 years and further subdivided into an MCI-stable group (MCI-S, n = 36) and an MCI-converted group (MCI-C, n = 36). The HHSA was then applied to the rsEEG data, and features were extracted and subjected to machine-learning algorithms. Results (a) At the group level analysis, the HHSA contrast of MCI and different stages of AD showed augmented amplitude modulation (AM) power of lower-frequency oscillations (LFO; delta and theta bands) with attenuated AM power of higher-frequency oscillations (HFO; beta and gamma bands) compared with cognitively normal elderly controls. The alpha frequency oscillation showed augmented AM power across MCI to AD1 with a reverse trend at AD2. (b) At the individual level of cross-sectional analysis, implementation of machine learning algorithms discriminated between groups with good sensitivity (Sen) and specificity (Spec) as follows: CN elderly vs. MCI: 0.82 (Sen)/0.80 (Spec), CN vs. AD1: 0.94 (Sen)/0.80 (Spec), CN vs. AD2: 0.93 (Sen)/0.90 (Spec), and CN vs. AD3: 0.75 (Sen)/1.00 (Spec). (c) In the longitudinal MCI follow-up, the initial contrasted HHSA between MCI-S and MCI-C groups showed significantly attenuated AM power of alpha and beta band oscillations. (d) At the individual level analysis of longitudinal MCI groups, deploying machine learning algorithms with the best seven features resulted in a sensitivity of 0.9 by the support vector machine (SVM) classifier, with a specificity of 0.8 yielded by the decision tree classifier. Conclusion Integrating HHSA into EEG signals and machine learning algorithms can differentiate between CN and MCI as well as also predict AD progression at the MCI stage.
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Affiliation(s)
- Kwo-Ta Chu
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Yang-Ming Hospital, Taoyuan, Taiwan
| | - Weng-Chi Lei
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
| | - Ming-Hsiu Wu
- Division of Neurology, Department of Internal Medicine, Chi Mei Medical Center, Tainan, Taiwan
- Department of Long-Term Care and Health Promotion, Min-Hwei Junior College of Health Care Management, Tainan, Taiwan
| | - Jong-Ling Fuh
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shuu-Jiun Wang
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Isobel T. French
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Central University and Academia Sinica, Taipei, Taiwan
| | - Wen-Sheng Chang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
| | - Chi-Fu Chang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
| | - Norden E. Huang
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
- Key Laboratory of Data Analysis and Applications, First Institute of Oceanography, SOA, Qingdao, China
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan
- Department of Psychology, Kaohsiung Medical University, Kaohsiung, Taiwan
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Chang X, Shen C, Liu S, Zheng D, Wang S, Yang C, Huang NE, Bian L. Robust Kramers-Kronig holographic imaging with Hilbert-Huang transform. Opt Lett 2023; 48:4161-4164. [PMID: 37527143 DOI: 10.1364/ol.495895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/15/2023] [Indexed: 08/03/2023]
Abstract
Holography based on Kramers-Kronig relations (KKR) is a promising technique due to its high-space-bandwidth product. However, the absence of an iterative process limits its noise robustness, primarily stemming from the lack of a regularization constraint. This Letter reports a generalized framework aimed at enhancing the noise robustness of KKR holography. Our proposal involves employing the Hilbert-Huang transform to connect the real and imaginary parts of an analytic function. The real part is initially processed by bidimensional empirical mode decomposition into a series of intrinsic mode functions (IMFs) and a residual term. They are then selected to remove the noise and bias terms. Finally, the imaginary part can be obtained using the Hilbert transform. In this way, we efficiently suppress the noise in the synthetic complex function, facilitating high-fidelity wavefront reconstruction using ∼20% of the exposure time required by existing methods. Our work is expected to expand the applications of KKR holography, particularly in low phototoxicity biological imaging and other related scenarios.
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Jaiswal S, Huang SL, Juan CH, Huang NE, Liang WK. Resting state dynamics in people with varying degrees of anxiety and mindfulness: A nonlinear and nonstationary perspective. Neuroscience 2023; 519:177-197. [PMID: 36966877 DOI: 10.1016/j.neuroscience.2023.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/16/2023] [Accepted: 03/11/2023] [Indexed: 03/29/2023]
Abstract
Anxiety and mindfulness are two inversely linked traits shown to be involved in various physiological domains. The current study used resting state electroencephalography (EEG) to explore differences between people with low mindfulness-high anxiety (LMHA) (n = 29) and high mindfulness-low anxiety (HMLA) (n = 27). The resting EEG was collected for a total of 6 min, with a randomized sequence of eyes closed and eyes opened conditions. Two advanced EEG analysis methods, Holo-Hilbert Spectral Analysis and Holo-Hilbert cross-frequency phase clustering (HHCFPC) were employed to estimate the power-based amplitude modulation of carrier frequencies, and cross-frequency coupling between low and high frequencies, respectively. The presence of higher oscillation power across the delta and theta frequencies in the LMHA group than the HMLA group might have been due to the similarity between the resting state and situations of uncertainty, which reportedly triggers motivational and emotional arousal. Although these two groups were formed based on their trait anxiety and trait mindfulness scores, it was anxiety that was found to be significant predictor of the EEG power, not mindfulness. It led us to conclude that it might be anxiety, not mindfulness, which might have contributed to higher electrophysiological arousal. Additionally, a higher δ-β and δ-γ CFC in LMHA suggested greater local-global neural integration, consequently a greater functional association between cortex and limbic system than in the HMLA group. The present cross-sectional study may guide future longitudinal studies on anxiety aiming with interventions such as mindfulness to characterize the individuals based on their resting state physiology.
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Yang AC, Peng CK, Huang NE. Reply To: Comments on identifying causal relationships in nonlinear dynamical systems via empirical mode decomposition. Nat Commun 2022; 13:2859. [PMID: 35606371 PMCID: PMC9127069 DOI: 10.1038/s41467-022-30360-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 04/25/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Albert C Yang
- Institute of Brain Science/Digital Medicine and Smart Healthcare Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan.
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan.
| | - Chung-Kang Peng
- Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, 02215, USA
| | - Norden E Huang
- Key Laboratory of Data Analysis and Applications, First Institute of Oceanography, SOA, Qingdao, 266061, China
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Chang KH, French IT, Liang WK, Lo YS, Wang YR, Cheng ML, Huang NE, Wu HC, Lim SN, Chen CM, Juan CH. Evaluating the Different Stages of Parkinson's Disease Using Electroencephalography With Holo-Hilbert Spectral Analysis. Front Aging Neurosci 2022; 14:832637. [PMID: 35619940 PMCID: PMC9127298 DOI: 10.3389/fnagi.2022.832637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/08/2022] [Indexed: 01/04/2023] Open
Abstract
Electroencephalography (EEG) can reveal the abnormalities of dopaminergic subcortico-cortical circuits in patients with Parkinson's disease (PD). However, conventional time-frequency analysis of EEG signals cannot fully reveal the non-linear processes of neural activities and interactions. A novel Holo-Hilbert Spectral Analysis (HHSA) was applied to reveal non-linear features of resting state EEG in 99 PD patients and 59 healthy controls (HCs). PD patients demonstrated a reduction of β bands in frontal and central regions, and reduction of γ bands in central, parietal, and temporal regions. Compared with early-stage PD patients, late-stage PD patients demonstrated reduction of β bands in the posterior central region, and increased θ and δ2 bands in the left parietal region. θ and β bands in all brain regions were positively correlated with Hamilton depression rating scale scores. Machine learning algorithms using three prioritized HHSA features demonstrated "Bag" with the best accuracy of 0.90, followed by "LogitBoost" with an accuracy of 0.89. Our findings strengthen the application of HHSA to reveal high-dimensional frequency features in EEG signals of PD patients. The EEG characteristics extracted by HHSA are important markers for the identification of depression severity and diagnosis of PD.
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Affiliation(s)
- Kuo-Hsuan Chang
- Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Isobel Timothea French
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Central University and Academia Sinica, Taipei, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Research Center, National Central University, Taoyuan, Taiwan
| | - Yen-Shi Lo
- Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Yi-Ru Wang
- Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Mei-Ling Cheng
- Department of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
- Metabolomics Core Laboratory, Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
- Clinical Phenome Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Norden E. Huang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Research Center, National Central University, Taoyuan, Taiwan
- Data Analysis and Application Laboratory, The First Institute of Oceanography, Qingdao, China
| | - Hsiu-Chuan Wu
- Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Siew-Na Lim
- Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Chiung-Mei Chen
- Department of Neurology, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan
- Cognitive Intelligence and Precision Healthcare Research Center, National Central University, Taoyuan, Taiwan
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Tsai YC, Li CT, Liang WK, Muggleton NG, Tsai CC, Huang NE, Juan CH. Critical role of rhythms in prefrontal transcranial magnetic stimulation for depression: A randomized sham-controlled study. Hum Brain Mapp 2021; 43:1535-1547. [PMID: 34873781 PMCID: PMC8886663 DOI: 10.1002/hbm.25740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/25/2021] [Accepted: 11/28/2021] [Indexed: 11/21/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is an alternative treatment for depression, but the neural correlates of the treatment are currently inconclusive, which might be a limit of conventional analytical methods. The present study aimed to investigate the neurophysiological evidence and potential biomarkers for rTMS and intermittent theta burst stimulation (iTBS) treatment. A total of 61 treatment‐resistant depression patients were randomly assigned to receive prolonged iTBS (piTBS; N = 19), 10 Hz rTMS (N = 20), or sham stimulation (N = 22). Each participant went through a treatment phase with resting state electroencephalography (EEG) recordings before and after the treatment phase. The aftereffects of stimulation showed that theta‐alpha amplitude modulation frequency (fam) was associated with piTBS_Responder, which involves repetitive bursts delivered in the theta frequency range, whereas alpha carrier frequency (fc) was related to 10 Hz rTMS, which uses alpha rhythmic stimulation. In addition, theta‐alpha amplitude modulation frequency was positively correlated with piTBS antidepressant efficacy, whereas the alpha frequency was not associated with the 10 Hz rTMS clinical outcome. The present study showed that TMS stimulation effects might be lasting, with changes of brain oscillations associated with the delivered frequency. Additionally, theta‐alpha amplitude modulation frequency may be as a function of the degree of recovery in TRD with piTBS treatment and also a potential EEG‐based predictor of antidepressant efficacy of piTBS in the early treatment stage, that is, first 2 weeks.
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Affiliation(s)
- Yi-Chun Tsai
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan
| | - Cheng-Ta Li
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan.,Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Brain Science, National Yang-Ming Chiao-Tung University, Taipei, Taiwan.,Division of Psychiatry, Faculty of Medicine, National Yang-Ming Chiao-Tung University, Taipei, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan.,Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Neil G Muggleton
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan.,Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Chong-Chih Tsai
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan.,Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan.,Department of Psychiatry, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Norden E Huang
- Key Laboratory of Data Analysis and Applications, First Institute of Oceanography, State Oceanic Administration, Qingdao, China
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, College of Health Sciences and Technology, National Central University, Taoyuan City, Taiwan.,Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan.,Department of Psychology, Kaohsiung Medical University, Kaohsiung, Taiwan
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Huang NE, Qiao F, Wang Q, Qian H, Tung KK. A model for the spread of infectious diseases compatible with case data. Proc Math Phys Eng Sci 2021; 477:20210551. [PMID: 35153589 PMCID: PMC8511757 DOI: 10.1098/rspa.2021.0551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/06/2021] [Indexed: 11/12/2022] Open
Abstract
For epidemics such as COVID-19, with a significant population having asymptomatic, untested infection, model predictions are often not compatible with data reported only for the cases confirmed by laboratory tests. Additionally, most compartmental models have instantaneous recovery from infection, contrary to observation. Tuning such models with observed data to obtain the unknown infection rate is an ill-posed problem. Here, we derive from the first principle an epidemiological model with delay between the newly infected (N) and recovered (R) populations. To overcome the challenge of incompatibility between model and case data, we solve for the ratios of the observed quantities and show that log(N(t)/R(t)) should follow a straight line. This simple prediction tool is accurate in hindcasts verified using data for China and Italy. In traditional epidemiology, an epidemic wanes when much of the population is infected so that 'herd immunity' is achieved. For a highly contagious and deadly disease, herd immunity is not a feasible goal without human intervention or vaccines. Even before the availability of vaccines, the epidemic was suppressed with social measures in China and South Korea with much less than 5% of the population infected. Effects of social behaviour should be and are incorporated in our model.
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Affiliation(s)
- Norden E. Huang
- Data Analysis Laboratory, First Institute of Oceanography, Qingdao 266061, People's Republic of China
| | - Fangli Qiao
- Data Analysis Laboratory, First Institute of Oceanography, Qingdao 266061, People's Republic of China
| | - Qian Wang
- Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Hong Qian
- Department of Applied Mathematics, University of Washington, Seattle, WA 98195, USA
| | - Ka-Kit Tung
- Department of Applied Mathematics, University of Washington, Seattle, WA 98195, USA
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Juan CH, Nguyen KT, Liang WK, Quinn AJ, Chen YH, Muggleton NG, Yeh JR, Woolrich MW, Nobre AC, Huang NE. Revealing the Dynamic Nature of Amplitude Modulated Neural Entrainment With Holo-Hilbert Spectral Analysis. Front Neurosci 2021; 15:673369. [PMID: 34421511 PMCID: PMC8375503 DOI: 10.3389/fnins.2021.673369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 07/14/2021] [Indexed: 12/11/2022] Open
Abstract
Patterns in external sensory stimuli can rapidly entrain neuronally generated oscillations observed in electrophysiological data. Here, we manipulated the temporal dynamics of visual stimuli with cross-frequency coupling (CFC) characteristics to generate steady-state visual evoked potentials (SSVEPs). Although CFC plays a pivotal role in neural communication, some cases reporting CFC may be false positives due to non-sinusoidal oscillations that can generate artificially inflated coupling values. Additionally, temporal characteristics of dynamic and non-linear neural oscillations cannot be fully derived with conventional Fourier-based analyses mainly due to trade off of temporal resolution for frequency precision. In an attempt to resolve these limitations of linear analytical methods, Holo-Hilbert Spectral Analysis (HHSA) was investigated as a potential approach for examination of non-linear and non-stationary CFC dynamics in this study. Results from both simulation and SSVEPs demonstrated that temporal dynamic and non-linear CFC features can be revealed with HHSA. Specifically, the results of simulation showed that the HHSA is less affected by the non-sinusoidal oscillation and showed possible cross frequency interactions embedded in the simulation without any a priori assumptions. In the SSVEPs, we found that the time-varying cross-frequency interaction and the bidirectional coupling between delta and alpha/beta bands can be observed using HHSA, confirming dynamic physiological signatures of neural entrainment related to cross-frequency coupling. These findings not only validate the efficacy of the HHSA in revealing the natural characteristics of signals, but also shed new light on further applications in analysis of brain electrophysiological data with the aim of understanding the functional roles of neuronal oscillation in various cognitive functions.
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Affiliation(s)
- Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
- Department of Psychology, Kaohsiung Medical University, Kaohsiung City, Taiwan
| | - Kien Trong Nguyen
- Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan
- Faculty of Electronics Engineering, Posts and Telecommunications Institute of Technology, Ho Chi Minh City, Vietnam
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Andrew J. Quinn
- Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
| | - Yen-Hsun Chen
- Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan
| | - Neil G. Muggleton
- Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
- Department of Psychology, Goldsmiths, University of London, London, United Kingdom
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom
| | - Jia-Rong Yeh
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
| | - Mark W. Woolrich
- Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
| | - Anna C. Nobre
- Oxford Centre for Human Brain Activity, University of Oxford, Oxford, United Kingdom
- Wellcome Centre for Integrative Neuroimaging, University of Oxford, Oxford, United Kingdom
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Norden E. Huang
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan
- Data Analysis and Application Laboratory, The First Institute of Oceanography, Qingdao, China
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11
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Liang WK, Tseng P, Yeh JR, Huang NE, Juan CH. Frontoparietal Beta Amplitude Modulation and its Interareal Cross-frequency Coupling in Visual Working Memory. Neuroscience 2021; 460:69-87. [PMID: 33588001 DOI: 10.1016/j.neuroscience.2021.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 02/08/2021] [Accepted: 02/08/2021] [Indexed: 01/19/2023]
Abstract
Visual working memory (VWM) relies on sustained neural activities that code information via various oscillatory frequencies. Previous studies, however, have emphasized time-frequency power changes, while overlooking the possibility that rhythmic amplitude variations can also code frequency-specific VWM information in a completely different dimension. Here, we employed the recently-developed Holo-Hilbert spectral analysis to characterize such nonlinear amplitude modulation(s) (AM) underlying VWM in the frontoparietal systems. We found that the strength of AM in mid-frontal beta and gamma oscillations during late VWM maintenance and VWM retrieval correlated with people's VWM performance. When behavioral performance was altered with transcranial electric stimulation, AM power changes during late VWM maintenance in beta, but not gamma, tracked participants' VWM variations. This beta AM likely codes information by varying its amplitude in theta period for long-range propagation, as our connectivity analysis revealed that interareal theta-beta couplings-bidirectional between mid-frontal and right-parietal during VWM maintenance and unidirectional from right-parietal to left-middle-occipital during late VWM maintenance and retrieval-underpins VWM performance and individual differences.
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Affiliation(s)
- Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan; Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan; Brain Research Center, College of Health Sciences and Technology, National Central University, Taoyuan, Taiwan.
| | - Philip Tseng
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Center, TMU-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Jia-Rong Yeh
- Brain Research Center, College of Health Sciences and Technology, National Central University, Taoyuan, Taiwan; Data Analysis and Application Laboratory, The First Institute of Oceanography, Qingdao, China
| | - Norden E Huang
- Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan; Brain Research Center, College of Health Sciences and Technology, National Central University, Taoyuan, Taiwan; Data Analysis and Application Laboratory, The First Institute of Oceanography, Qingdao, China
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan; Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan, Taiwan; Brain Research Center, College of Health Sciences and Technology, National Central University, Taoyuan, Taiwan; Department of Psychology, Kaohsiung Medical University, Kaohsiung, Taiwan
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12
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Affiliation(s)
- Norden E Huang
- First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, China; Key Laboratory of Marine Science and Numerical Modeling, Ministry of Natural Resources of China, Qingdao 266061, China
| | - Fangli Qiao
- First Institute of Oceanography, Ministry of Natural Resources of China, Qingdao 266061, China; Laboratory for Regional Oceanography and Numerical Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China; National Engineering Laboratory for Integrated Aero-Space-Ground-Ocean Big Data Application Technology, Qingdao 266061, China.
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13
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14
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Nguyen KT, Liang WK, Muggleton NG, Huang NE, Juan CH. Human visual steady-state responses to amplitude-modulated flicker: Latency measurement. J Vis 2019; 19:14. [PMID: 31845974 DOI: 10.1167/19.14.14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The response latency of steady-state visually evoked potentials (SSVEPs) is a sensitive measurement for investigating visual functioning of the human brain, specifically in visual development and for clinical evaluation. This latency can be measured from the slope of phase versus frequency of responses by using multiple frequencies of stimuli. In an attempt to provide an alternative measurement of this latency, this study utilized an envelope response of SSVEPs elicited by amplitude-modulated visual stimulation and then compared with the envelope of the generating signal, which was recorded simultaneously with the electroencephalography recordings. The advantage of this measurement is that it successfully estimates the response latency based on the physiological envelope in the entire waveform. Results showed the response latency at the occipital lobe (Oz channel) was approximately 104.55 ms for binocular stimulation, 97.14 ms for the dominant eye, and 104.75 ms for the nondominant eye with no significant difference between these stimulations. Importantly, the response latency at frontal channels (125.84 ms) was significantly longer than that at occipital channels (104.11 ms) during binocular stimulation. Together with strong activation of the source envelope at occipital cortex, these findings support the idea of a feedforward process, with the visual stimuli propagating originally from occipital cortex to anterior cortex. In sum, these findings offer a novel method for future studies in measuring visual response latencies and also potentially shed a new light on understanding of how long collective neural activities take to travel in the human brain.
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Affiliation(s)
- Kien Trong Nguyen
- Institute of Cognitive Neuroscience, National Central University, Taiwan
| | - Wei-Kuang Liang
- Institute of Cognitive Neuroscience, National Central University, Taiwan.,Brain Research Center, National Central University, Taiwan
| | - Neil G Muggleton
- Institute of Cognitive Neuroscience, National Central University, Taiwan.,Brain Research Center, National Central University, Taiwan.,Institute of Cognitive Neuroscience, University College London, London, UK.,Department of Psychology, Goldsmiths, University of London, London, UK
| | - Norden E Huang
- Brain Research Center, National Central University, Taiwan.,Data Analysis and Application Laboratory, The First Institute of Oceanography, Qingdao, China.,Pilot National Laboratory of Marine Science and Technology, Qingdao, China
| | - Chi-Hung Juan
- Institute of Cognitive Neuroscience, National Central University, Taiwan.,Brain Research Center, National Central University, Taiwan
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15
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Abstract
Inference of causality in time series has been principally based on the prediction paradigm. Nonetheless, the predictive causality approach may underestimate the simultaneous and reciprocal nature of causal interactions observed in real-world phenomena. Here, we present a causal-decomposition approach that is not based on prediction, but based on the covariation of cause and effect: cause is that which put, the effect follows; and removed, the effect is removed. Using empirical mode decomposition, we show that causal interaction is encoded in instantaneous phase dependency at a specific time scale, and this phase dependency is diminished when the causal-related intrinsic component is removed from the effect. Furthermore, we demonstrate the generic applicability of our method to both stochastic and deterministic systems, and show the consistency of causal-decomposition method compared to existing methods, and finally uncover the key mode of causal interactions in both modelled and actual predator–prey systems. Causality inference in time series analysis based on temporal precedence principle between cause and effect fails to detect mutual causal interactions. Here, Yang et al. introduce a causal decomposition approach based on the covariation principle of cause and effect that overcomes this limitation.
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Affiliation(s)
- Albert C Yang
- Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, 02215, USA. .,Institute of Brain Science, National Yang-Ming University, 11221, Taipei, Taiwan. .,Department of Psychiatry, Taipei Veterans General Hospital, 11217, Taipei, Taiwan.
| | - Chung-Kang Peng
- Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, 02215, USA
| | - Norden E Huang
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, 32001, Chungli, Taiwan.,Key Laboratory of Data Analysis and Applications, First Institute of Oceanography, SOA, 266061, Qingdao, China
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16
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Yang AC, Tsai SJ, Lin CP, Peng CK, Huang NE. Frequency and amplitude modulation of resting-state fMRI signals and their functional relevance in normal aging. Neurobiol Aging 2018; 70:59-69. [PMID: 30007165 DOI: 10.1016/j.neurobiolaging.2018.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/24/2018] [Accepted: 06/04/2018] [Indexed: 01/31/2023]
Abstract
The intrinsic composition and functional relevance of resting-state blood oxygen level-dependent signals are fundamental in research using functional magnetic resonance imaging (fMRI). Using the Hilbert-Huang Transform to estimate high-resolution time-frequency spectra, we investigated the instantaneous frequency and amplitude modulation of resting-state fMRI signals, as well as their functional relevance in a large normal-aging cohort (n = 420, age = 21-89 years). We evaluated the cognitive function of each participant and recorded respiratory signals during fMRI scans. The results showed that the Hilbert-Huang Transform effectively categorized resting-state fMRI power spectra into high (0.087-0.2 Hz), low (0.045-0.087 Hz), and very-low (≤0.045 Hz) frequency bands. The high-frequency power was associated with respiratory activity, and the low-frequency power was associated with cognitive function. Furthermore, within the cognition-related low-frequency band (0.045-0.087 Hz), we discovered that aging was associated with the increased frequency modulation and reduced amplitude modulation of the resting-state fMRI signal. These aging-related changes in frequency and amplitude modulation of resting-state fMRI signals were unaccounted for by the loss of gray matter volume and were consistently identified in the default mode and salience network. These findings indicate that resting-state fMRI signal modulations are dynamic during the normal aging process. In summary, our results refined the functionally related blood oxygen level-dependent frequency band in a considerably narrow band at a low-frequency range (0.045-0.087 Hz) and challenged the current method of resting-fMRI preprocessing by using low-frequency filters with a relatively wide range below 0.1 Hz.
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Affiliation(s)
- Albert C Yang
- Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA; Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.
| | - Shih-Jen Tsai
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan; Division of Psychiatry, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ching-Po Lin
- Division of Psychiatry, School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Chung-Kang Peng
- Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
| | - Norden E Huang
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan
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17
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Liu MY, Huang A, Huang NE. Evaluating and Improving Automatic Sleep Spindle Detection by Using Multi-Objective Evolutionary Algorithms. Front Hum Neurosci 2017; 11:261. [PMID: 28572762 PMCID: PMC5435763 DOI: 10.3389/fnhum.2017.00261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 05/02/2017] [Indexed: 11/13/2022] Open
Abstract
Sleep spindles are brief bursts of brain activity in the sigma frequency range (11–16 Hz) measured by electroencephalography (EEG) mostly during non-rapid eye movement (NREM) stage 2 sleep. These oscillations are of great biological and clinical interests because they potentially play an important role in identifying and characterizing the processes of various neurological disorders. Conventionally, sleep spindles are identified by expert sleep clinicians via visual inspection of EEG signals. The process is laborious and the results are inconsistent among different experts. To resolve the problem, numerous computerized methods have been developed to automate the process of sleep spindle identification. Still, the performance of these automated sleep spindle detection methods varies inconsistently from study to study. There are two reasons: (1) the lack of common benchmark databases, and (2) the lack of commonly accepted evaluation metrics. In this study, we focus on tackling the second problem by proposing to evaluate the performance of a spindle detector in a multi-objective optimization context and hypothesize that using the resultant Pareto fronts for deriving evaluation metrics will improve automatic sleep spindle detection. We use a popular multi-objective evolutionary algorithm (MOEA), the Strength Pareto Evolutionary Algorithm (SPEA2), to optimize six existing frequency-based sleep spindle detection algorithms. They include three Fourier, one continuous wavelet transform (CWT), and two Hilbert-Huang transform (HHT) based algorithms. We also explore three hybrid approaches. Trained and tested on open-access DREAMS and MASS databases, two new hybrid methods of combining Fourier with HHT algorithms show significant performance improvement with F1-scores of 0.726–0.737.
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Affiliation(s)
- Min-Yin Liu
- Department of Biomedical Sciences and Engineering, Institute of Systems Biology and Bioinformatics, National Central UniversityTaoyuan, Taiwan
| | - Adam Huang
- Research Center for Adaptive Data Analysis, National Central UniversityTaoyuan, Taiwan
| | - Norden E Huang
- Department of Biomedical Sciences and Engineering, Institute of Systems Biology and Bioinformatics, National Central UniversityTaoyuan, Taiwan.,Research Center for Adaptive Data Analysis, National Central UniversityTaoyuan, Taiwan
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18
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Tsai FF, Fan SZ, Lin YS, Huang NE, Yeh JR. Investigating Power Density and the Degree of Nonlinearity in Intrinsic Components of Anesthesia EEG by the Hilbert-Huang Transform: An Example Using Ketamine and Alfentanil. PLoS One 2016; 11:e0168108. [PMID: 27973590 PMCID: PMC5156388 DOI: 10.1371/journal.pone.0168108] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 11/26/2016] [Indexed: 11/22/2022] Open
Abstract
Empirical mode decomposition (EMD) is an adaptive filter bank for processing nonlinear and non-stationary signals, such as electroencephalographic (EEG) signals. EMD works well to decompose a time series into a set of intrinsic mode functions with specific frequency bands. An IMF therefore represents an intrinsic component on its correspondingly intrinsic frequency band. The word of 'intrinsic' means the frequency is totally adaptive to the nature of a signal. In this study, power density and nonlinearity are two critical parameters for characterizing the amplitude and frequency modulations in IMFs. In this study, a nonlinearity level is quantified using degree of waveform distortion (DWD), which represents the characteristic of waveform distortion as an assessment of the intra-wave modulation of an IMF. In the application of anesthesia EEG analysis, the assessments of power density and DWD for a set of IMFs represent dynamic responses in EEG caused by two different anesthesia agents, Ketamine and Alfentanil, on different frequency bands. Ketamine causes the increase of power density and the decrease of nonlinearity on γ-band neuronal oscillation, which cannot be found EEG responses of group B using Alfentanil. Both agents cause an increase of power density and a decrease of nonlinearity on β-band neuronal oscillation accompany with a loss of consciousness. Moreover, anesthesia agents cause the decreases of power density and nonlinearity (i.e. DWD) for the low-frequency IMFs.
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Affiliation(s)
- Feng-Fang Tsai
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Anesthesiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Rey Institute for Nonlinear Dynamics in Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States of America
| | - Shou-Zen Fan
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Anesthesiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Shiuan Lin
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan
| | - Norden E. Huang
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Taoyuan, Taiwan
- Research Center for Adaptive Data Analysis, National Central University, Taoyuan, Taiwan
| | - Jia-Rong Yeh
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Taoyuan, Taiwan
- Research Center for Adaptive Data Analysis, National Central University, Taoyuan, Taiwan
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19
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Lin YJ, Lo MT, Chang SL, Lo LW, Hu YF, Chao TF, Chung FP, Liao JN, Lin CY, Kuo HY, Chang YC, Lin C, Tuan TC, Vincent Young HW, Suenari K, Dan Do VB, Raharjo SB, Huang NE, Chen SA. Benefits of Atrial Substrate Modification Guided by Electrogram Similarity and Phase Mapping Techniques to Eliminate Rotors and Focal Sources Versus Conventional Defragmentation in Persistent Atrial Fibrillation. JACC Clin Electrophysiol 2016; 2:667-678. [DOI: 10.1016/j.jacep.2016.08.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 07/20/2016] [Accepted: 08/04/2016] [Indexed: 10/21/2022]
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20
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Abstract
Multi-scale entropy (MSE) was developed as a measure of complexity for complex time series, and it has been applied widely in recent years. The MSE algorithm is based on the assumption that biological systems possess the ability to adapt and function in an ever-changing environment, and these systems need to operate across multiple temporal and spatial scales, such that their complexity is also multi-scale and hierarchical. Here, we present a systematic approach to apply the empirical mode decomposition algorithm, which can detrend time series on various time scales, prior to analysing a signal's complexity by measuring the irregularity of its dynamics on multiple time scales. Simulated time series of fractal Gaussian noise and human heartbeat time series were used to study the performance of this new approach. We show that our method can successfully quantify the fractal properties of the simulated time series and can accurately distinguish modulations in human heartbeat time series in health and disease.
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Affiliation(s)
- Jia-Rong Yeh
- Research Center for Adaptive Data Analysis and Center for Dynamical Biomarkers and Translational Medicine, National Central University, Taoyuan, Taiwan, Republic of China
| | - Chung-Kang Peng
- Research Center for Adaptive Data Analysis and Center for Dynamical Biomarkers and Translational Medicine, National Central University, Taoyuan, Taiwan, Republic of China Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
| | - Norden E Huang
- Research Center for Adaptive Data Analysis and Center for Dynamical Biomarkers and Translational Medicine, National Central University, Taoyuan, Taiwan, Republic of China
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21
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Huang NE, Daubechies I, Hou TY. Adaptive data analysis: theory and applications. Philos Trans A Math Phys Eng Sci 2016; 374:20150207. [PMID: 26953179 PMCID: PMC4792413 DOI: 10.1098/rsta.2015.0207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/19/2016] [Indexed: 06/05/2023]
Affiliation(s)
- Norden E Huang
- Research Centre for Adaptive Data Analysis, National Central University, Taiwan, Republic of China
| | | | - Thomas Y Hou
- Applied and Computational Mathematics, Caltech, 1200 E California Boulevard, Pasadena, CA, USA
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22
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Huang NE, Hu K, Yang ACC, Chang HC, Jia D, Liang WK, Yeh JR, Kao CL, Juan CH, Peng CK, Meijer JH, Wang YH, Long SR, Wu Z. On Holo-Hilbert spectral analysis: a full informational spectral representation for nonlinear and non-stationary data. Philos Trans A Math Phys Eng Sci 2016; 374:20150206. [PMID: 26953180 PMCID: PMC4792412 DOI: 10.1098/rsta.2015.0206] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/10/2015] [Indexed: 05/24/2023]
Abstract
The Holo-Hilbert spectral analysis (HHSA) method is introduced to cure the deficiencies of traditional spectral analysis and to give a full informational representation of nonlinear and non-stationary data. It uses a nested empirical mode decomposition and Hilbert-Huang transform (HHT) approach to identify intrinsic amplitude and frequency modulations often present in nonlinear systems. Comparisons are first made with traditional spectrum analysis, which usually achieved its results through convolutional integral transforms based on additive expansions of an a priori determined basis, mostly under linear and stationary assumptions. Thus, for non-stationary processes, the best one could do historically was to use the time-frequency representations, in which the amplitude (or energy density) variation is still represented in terms of time. For nonlinear processes, the data can have both amplitude and frequency modulations (intra-mode and inter-mode) generated by two different mechanisms: linear additive or nonlinear multiplicative processes. As all existing spectral analysis methods are based on additive expansions, either a priori or adaptive, none of them could possibly represent the multiplicative processes. While the earlier adaptive HHT spectral analysis approach could accommodate the intra-wave nonlinearity quite remarkably, it remained that any inter-wave nonlinear multiplicative mechanisms that include cross-scale coupling and phase-lock modulations were left untreated. To resolve the multiplicative processes issue, additional dimensions in the spectrum result are needed to account for the variations in both the amplitude and frequency modulations simultaneously. HHSA accommodates all the processes: additive and multiplicative, intra-mode and inter-mode, stationary and non-stationary, linear and nonlinear interactions. The Holo prefix in HHSA denotes a multiple dimensional representation with both additive and multiplicative capabilities.
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Affiliation(s)
- Norden E Huang
- Research Center for Adaptive Data Analysis, National Central University, Zhongli 32001, Taiwan, Republic of China
| | - Kun Hu
- Medical Biodynamics Program, Division of Sleep Medicine, Brigham and Women's Hospital/Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA
| | - Albert C C Yang
- Department of Psychiatry, Taipei Veteran General Hospital, Shipai 11217, Taiwan, Republic of China
| | - Hsing-Chih Chang
- Research Center for Adaptive Data Analysis, National Central University, Zhongli 32001, Taiwan, Republic of China
| | - Deng Jia
- The First Research Institution of Oceanography, SOA, Qingdao 266061, People's Republic of China
| | - Wei-Kuang Liang
- Graduate Institute of Cognitive Neuroscience, National Central University, Zhongli 32001, Taiwan, Republic of China
| | - Jia Rong Yeh
- Research Center for Adaptive Data Analysis, National Central University, Zhongli 32001, Taiwan, Republic of China
| | - Chu-Lan Kao
- Research Center for Adaptive Data Analysis, National Central University, Zhongli 32001, Taiwan, Republic of China
| | - Chi-Hung Juan
- Graduate Institute of Cognitive Neuroscience, National Central University, Zhongli 32001, Taiwan, Republic of China
| | - Chung Kang Peng
- Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Johanna H Meijer
- Department of Molecular Cell Biology, Laboratory for Neurophysiology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands
| | - Yung-Hung Wang
- Research Center for Adaptive Data Analysis, National Central University, Zhongli 32001, Taiwan, Republic of China
| | - Steven R Long
- NASA GSFC, Sciences and Exploration Directorate, Field Support Office, Code 610.W, Wallops Flight Facility, Wallops Island, VA 23337, USA
| | - Zhauhua Wu
- Department of Meteorology, Florida State University, 2035 E. Paul Dirac Drive, 200 R.M. Johnson Building, Tallahassee, FL 32306-2840, USA
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23
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Lin YC, Lin YH, Lo MT, Peng CK, Huang NE, Yang CCH, Kuo TBJ. Novel application of multi dynamic trend analysis as a sensitive tool for detecting the effects of aging and congestive heart failure on heart rate variability. Chaos 2016; 26:023109. [PMID: 26931590 DOI: 10.1063/1.4941673] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The complex fluctuations in heart rate variability (HRV) reflect cardiac autonomic modulation and are an indicator of congestive heart failure (CHF). This paper proposes a novel nonlinear approach to HRV investigation, the multi dynamic trend analysis (MDTA) method, based on the empirical mode decomposition algorithm of the Hilbert-Huang transform combined with a variable-sized sliding-window method. Electrocardiographic signal data obtained from the PhysioNet database were used. These data were from subjects with CHF (mean age = 59.4 ± 8.4), an age-matched elderly healthy control group (59.3 ± 10.6), and a healthy young group (30.3 ± 4.8); the HRVs of these subjects were processed using the MDTA method, time domain analysis, and frequency domain analysis. Among all HRV parameters, the MDTA absolute value slope (MDTS) and MDTA deviation (MDTD) exhibited the greatest area under the curve (AUC) of the receiver operating characteristics in distinguishing between the CHF group and the healthy controls (AUC = 1.000) and between the healthy elderly subject group and the young subject group (AUC = 0.834 ± 0.067 for MDTS; 0.837 ± 0.066 for MDTD). The CHF subjects presented with lower MDTA indices than those of the healthy elderly subject group. Furthermore, the healthy elderly subjects exhibited lower MDTA indices than those of the young controls. The MDTA method can adaptively and automatically identify the intrinsic fluctuation on variable temporal and spatial scales when investigating complex fluctuations in the cardiac autonomic regulation effects of aging and CHF.
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Affiliation(s)
- Yu-Cheng Lin
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Hsuan Lin
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Men-Tzung Lo
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Jhongli, Taiwan
| | - Chung-Kang Peng
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Jhongli, Taiwan
| | - Norden E Huang
- Research Center for Adaptive Data Analysis, National Central University, Taoyuan, Taiwan
| | - Cheryl C H Yang
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Terry B J Kuo
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
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24
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Lee HI, Huh CA, Lee T, Huang NE. Time series study of a 17-year record of (7)Be and (210)Pb fluxes in northern Taiwan using ensemble empirical mode decomposition. J Environ Radioact 2015; 147:14-21. [PMID: 26005772 DOI: 10.1016/j.jenvrad.2015.04.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 04/08/2015] [Accepted: 04/27/2015] [Indexed: 06/04/2023]
Abstract
Using the ensemble empirical mode decomposition (EEMD) and a significance test method, we have analyzed time series data on the fluxes of (7)Be and (210)Pb collected over a span of 17 y in Northern Taiwan. Among nine intrinsic mode functions (IMFs) extracted from the method five (IMF4-8) are non-trivial for (210)Pb and have adequate S/N with significant power in localized windows around the periodicities of 0.5 y, 1 y, 2 y, 5 y, and 11 y, respectively. For (7)Be, IMF5 and IMF8 with periods around 1 y and 11 y, respectively, have adequate S/N. The semi-annual and annual cycles represented by IMF4 and IMF5, respectively, are dominated by East Asian monsoon. The sum of IMF6 and IMF7 reveals an inter-annual cycle where both (7)Be and (210)Pb fluxes are well-correlated with the East Asian winter monsoon index (EAWMI). The close tracking of the (210)Pb and (7)Be in IMF8 cases may reflect an 11 y cycle; implying that it is caused by common climatologic factors, likely related to solar cycle, rather than their distinct production modes.
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Affiliation(s)
- H-I Lee
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan; Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, USA.
| | - C-A Huh
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan.
| | - T Lee
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan
| | - N E Huang
- Research Center for Adaptive Data Analysis, National Central University, Zhongli, Taiwan
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25
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Yang AC, Fuh JL, Huang NE, Shia BC, Wang SJ. Patients with migraine are right about their perception of temperature as a trigger: time series analysis of headache diary data. J Headache Pain 2015; 16:533. [PMID: 26018293 PMCID: PMC4446287 DOI: 10.1186/s10194-015-0533-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 05/19/2015] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Researches to date on the association between headache and weather have yielded inconsistent results. Only a limited number of studies have examined the clinical significance of self-reported weather sensitivity. This study aimed to identify the difference in the association of headache with temperature between migraine patients with and without temperature sensitivity. METHODS 66 migraine patients (75.8 % female; mean age 43.3 ± 12.9 years) provided their 1-year headache diaries from 2007 to a headache clinic in Taipei, Taiwan. 34 patients (51.5 %) reported sensitivity to temperature change but 32 (48.5 %) did not. Time series of daily headache incidence was modeled and stratified by temperature sensitivity. Empirical mode decomposition was used to identify temporal weather patterns that were correlated to headache incidence, and regression analysis was used to examine the amount of variance in headache incidence that could be explained by temperature in different seasons. RESULTS Among all migraine patients, temperature change accounted for 16.5 % of variance in headache incidence in winter and 9.6 % in summer. In winter, the explained variance increased to 29.2 % among patients with temperature sensitivity, but was not significant among those without temperature sensitivity. Overall, temperature change explained 27.0 % of the variance of the mild headache incidence but only 4.8 % of the incidence of moderate to severe headache during winter. CONCLUSIONS This diary-based study provides evidence to link the perception of temperature sensitivity and headache incidence in migraine patients. Those who reported temperature sensitivity are more likely to have headache increase during the winter, particular for mild headaches.
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Affiliation(s)
- Albert C Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
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Yang AC, Hong CJ, Liou YJ, Huang KL, Huang CC, Liu ME, Lo MT, Huang NE, Peng CK, Lin CP, Tsai SJ. Decreased resting-state brain activity complexity in schizophrenia characterized by both increased regularity and randomness. Hum Brain Mapp 2015; 36:2174-86. [PMID: 25664834 DOI: 10.1002/hbm.22763] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/27/2015] [Accepted: 01/30/2015] [Indexed: 11/10/2022] Open
Abstract
Schizophrenia is characterized by heterogeneous pathophysiology. Using multiscale entropy (MSE) analysis, which enables capturing complex dynamics of time series, we characterized MSE patterns of blood-oxygen-level-dependent (BOLD) signals across different time scales and determined whether BOLD activity in patients with schizophrenia exhibits increased complexity (increased entropy in all time scales), decreased complexity toward regularity (decreased entropy in all time scales), or decreased complexity toward uncorrelated randomness (high entropy in short time scales followed by decayed entropy as the time scale increases). We recruited 105 patients with schizophrenia with an age of onset between 18 and 35 years and 210 age- and sex-matched healthy volunteers. Results showed that MSE of BOLD signals in patients with schizophrenia exhibited two routes of decreased BOLD complexity toward either regular or random patterns. Reduced BOLD complexity toward regular patterns was observed in the cerebellum and temporal, middle, and superior frontal regions, and reduced BOLD complexity toward randomness was observed extensively in the inferior frontal, occipital, and postcentral cortices as well as in the insula and middle cingulum. Furthermore, we determined that the two types of complexity change were associated differently with psychopathology; specifically, the regular type of BOLD complexity change was associated with positive symptoms of schizophrenia, whereas the randomness type of BOLD complexity was associated with negative symptoms of the illness. These results collectively suggested that resting-state dynamics in schizophrenia exhibit two routes of pathologic change toward regular or random patterns, which contribute to the differences in syndrome domains of psychosis in patients with schizophrenia.
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Affiliation(s)
- Albert C Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan; Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts
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Huang NE. INTRODUCTION TO THE HILBERT–HUANG TRANSFORM AND ITS RELATED MATHEMATICAL PROBLEMS. Interdisciplinary Mathematical Sciences 2014. [DOI: 10.1142/9789814508247_0001] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Yang AC, Wang SJ, Lai KL, Tsai CF, Yang CH, Hwang JP, Lo MT, Huang NE, Peng CK, Fuh JL. Cognitive and neuropsychiatric correlates of EEG dynamic complexity in patients with Alzheimer's disease. Prog Neuropsychopharmacol Biol Psychiatry 2013; 47:52-61. [PMID: 23954738 DOI: 10.1016/j.pnpbp.2013.07.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 07/18/2013] [Accepted: 07/31/2013] [Indexed: 10/26/2022]
Abstract
This study assessed the utility of multiscale entropy (MSE), a complexity analysis of biological signals, to identify changes in dynamics of surface electroencephalogram (EEG) in patients with Alzheimer's disease (AD) that was correlated to cognitive and behavioral dysfunction. A total of 108 AD patients were recruited and their digital EEG recordings were analyzed using MSE methods. We investigate the appropriate parameters and time scale factors for MSE calculation from EEG signals. We then assessed the within-subject consistency of MSE measures in different EEG epochs and correlations of MSE measures to cognitive and neuropsychiatric symptoms of AD patients. Increased severity of AD was associated with decreased MSE complexity as measured by short-time scales, and with increased MSE complexity as measured by long-time scales. MSE complexity in EEGs of the temporal and occipitoparietal electrodes correlated significantly with cognitive function. MSE complexity of EEGs in various brain areas was also correlated to subdomains of neuropsychiatric symptoms. MSE analysis revealed abnormal EEG complexity across short- and long-time scales that were correlated to cognitive and neuropsychiatric assessments. The MSE-based EEG complexity analysis may provide a simple and cost-effective method to quantify the severity of cognitive and neuropsychiatric symptoms in AD patients.
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Affiliation(s)
- Albert C Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan
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Yang AC, Huang CC, Liu ME, Liou YJ, Hong CJ, Lo MT, Huang NE, Peng CK, Lin CP, Tsai SJ. The APOE ɛ4 allele affects complexity and functional connectivity of resting brain activity in healthy adults. Hum Brain Mapp 2013; 35:3238-48. [PMID: 24193893 DOI: 10.1002/hbm.22398] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 08/20/2013] [Indexed: 12/19/2022] Open
Abstract
The apolipoprotein E (APOE) gene is associated with structural and functional brain changes. We have used multiscale entropy (MSE) analysis to detect changes in the complexity of resting blood oxygen level-dependent (BOLD) signals associated with aging and cognitive function. In this study, we further hypothesized that the APOE genotype may affect the complexity of spontaneous BOLD activity in younger and older adults, and such altered complexity may be associated with certain changes in functional connectivity. We conducted a resting-state functional magnetic resonance imaging experiment in a cohort of 100 younger adults (aged 20-39 years; mean 27.2 ± 4.3 years; male/female: 53/47) and 112 older adults (aged 60-79 years; mean 68.4 ± 6.5 years; male/female: 54/58), and applied voxelwise MSE analysis to assess the main effect of APOE genotype on resting-state BOLD complexity and connectivity. Although the main effect of APOE genotype on BOLD complexity was not observed in younger group, we observed that older APOE ɛ4 allele carriers had significant reductions in BOLD complexity in precuneus and posterior cingulate regions, relative to noncarriers. We also observed that reduced BOLD complexity in precuneus and posterior cingulate regions was associated with increased functional connectivity to the superior and inferior frontal gyrus in the older group. These results support the compensatory recruitment hypothesis in older APOE ɛ4 carriers, and confer the impact of the APOE genotype on the temporal dynamics of brain activity in older adults.
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Affiliation(s)
- Albert C Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, School of Medicine National Yang-Ming University, Taipei, Taiwan; Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan
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Lin YJ, Lo MT, Lin C, Chang SL, Lo LW, Hu YF, Hsieh WH, Chang HY, Lin WY, Chung FP, Liao JN, Chen YY, Hanafy D, Huang NE, Chen SA. Prevalence, Characteristics, Mapping, and Catheter Ablation of Potential Rotors in Nonparoxysmal Atrial Fibrillation. Circ Arrhythm Electrophysiol 2013; 6:851-8. [DOI: 10.1161/circep.113.000318] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yenn-Jiang Lin
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Men-Tzung Lo
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Chen Lin
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Shih-Lin Chang
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Li-Wei Lo
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Yu-Feng Hu
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Wan-Hsin Hsieh
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Hung-Yu Chang
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Wen-Yu Lin
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Fa-Po Chung
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Jo-Nan Liao
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Yun-Yu Chen
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Dicky Hanafy
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Norden E. Huang
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
| | - Shih-Ann Chen
- From the Faculty of Medicine & Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., S.-A.C.); Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., H.-Y.C., W.-Y.L., F.-P.C., J.L., Y.-Y.C., D.H., S.-A.C.); Research Center for Adaptive Data Analysis (M.-T.L., C.L., W.-H.H., N.E.H.) and Center for Dynamical Biomarkers and
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Yang AC, Yang CH, Hong CJ, Liou YJ, Shia BC, Peng CK, Huang NE, Tsai SJ. Effects of Age, Sex, Index Admission, and Predominant Polarity on the Seasonality of Acute Admissions For Bipolar Disorder: A Population-Based Study. Chronobiol Int 2013; 30:478-85. [DOI: 10.3109/07420528.2012.741172] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Lin YJ, Suenari K, Lo MT, Lin C, Hsieh WH, Chang SL, Lo LW, Hu YF, Cheng CC, Kihara Y, Chao TF, Hartono B, Wu TJ, Lin WS, Hsu KH, Kibos AS, Huang NE, Chen SA. Novel Assessment of Temporal Variation in Fractionated Electrograms Using Histogram Analysis of Local Fractionation Interval in Patients With Persistent Atrial Fibrillation. Circ Arrhythm Electrophysiol 2012; 5:949-56. [DOI: 10.1161/circep.111.967612] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yenn-Jiang Lin
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Kazuyoshi Suenari
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Men-Tzung Lo
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Chen Lin
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Wan-Hsin Hsieh
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Shih-Lin Chang
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Li-Wei Lo
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Yu-Feng Hu
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Chen-Chuan Cheng
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Yasuki Kihara
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Tze-Fan Chao
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Beny Hartono
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Tsu-Juey Wu
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Wei-Shiang Lin
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Ke-Hsin Hsu
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Ambrose S. Kibos
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Norden E. Huang
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
| | - Shih-Ann Chen
- From the Division of Cardiology, Taipei Veterans General Hospital (Y.-J. L., K.S., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., B.H., A.S.K., S.-A.C.), Taipei, Taiwan; School of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University (Y.-J.L., S.-L.C., L.-W.L., Y.-F.H., T.-F.C., T.-J.W., S.-A.C.), Taipei, Taiwan; Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical Sciences (K.S., Y.K.), Hiroshima, Japan; Research Center for
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Yang AC, Huang CC, Yeh HL, Liu ME, Hong CJ, Tu PC, Chen JF, Huang NE, Peng CK, Lin CP, Tsai SJ. Complexity of spontaneous BOLD activity in default mode network is correlated with cognitive function in normal male elderly: a multiscale entropy analysis. Neurobiol Aging 2012; 34:428-38. [PMID: 22683008 DOI: 10.1016/j.neurobiolaging.2012.05.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/29/2012] [Accepted: 05/09/2012] [Indexed: 10/28/2022]
Abstract
The nonlinear properties of spontaneous fluctuations in blood oxygen level-dependent (BOLD) signals remain unexplored. We test the hypothesis that complexity of BOLD activity is reduced with aging and is correlated with cognitive performance in the elderly. A total of 99 normal older and 56 younger male subjects were included. Cognitive function was assessed using Cognitive Abilities Screening Instrument and Wechsler Digit Span Task. We employed a complexity measure, multiscale entropy (MSE) analysis, and investigated appropriate parameters for MSE calculation from relatively short BOLD signals. We then compared the complexity of BOLD signals between the younger and older groups, and examined the correlation between cognitive test scores and complexity of BOLD signals in various brain regions. Compared with the younger group, older subjects had the most significant reductions in MSE of BOLD signals in posterior cingulate gyrus and hippocampal cortex. For older subjects, MSE of BOLD signals from default mode network areas, including hippocampal cortex, cingulate cortex, superior and middle frontal gyrus, and middle temporal gyrus, were found to be positively correlated with major cognitive functions, such as attention, orientation, short-term memory, mental manipulation, and language. MSE from subcortical regions, such as amygdala and putamen, were found to be positively correlated with abstract thinking and list-generating fluency, respectively. Our findings confirmed the hypothesis that complexity of BOLD activity was correlated with aging and cognitive performance based on MSE analysis, and may provide insights on how dynamics of spontaneous brain activity relates to aging and cognitive function in specific brain regions.
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Affiliation(s)
- Albert C Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
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Yang AC, Tsai SJ, Huang NE, Peng CK. Association of Internet search trends with suicide death in Taipei City, Taiwan, 2004-2009. J Affect Disord 2011; 132:179-84. [PMID: 21371755 DOI: 10.1016/j.jad.2011.01.019] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 01/30/2011] [Accepted: 01/30/2011] [Indexed: 11/15/2022]
Abstract
BACKGROUND Although Internet has become an important source for affected people seeking suicide information, the connection between Internet searches for suicide information and suicidal death remains largely unknown. This study aims to evaluate the association between suicide and Internet searches trends for 37 suicide-related terms representing major known risks of suicide. METHODS This study analyzes suicide death data in Taipei City, Taiwan and corresponding local Internet search trend data provided by Google Insights for Search during the period from January 2004 to December 2009. The investigation uses cross correlation analysis to estimate the temporal relationship between suicide and Internet search trends and multiple linear regression analysis to identify significant factors associated with suicide from a pool of search trend data that either coincides or precedes the suicide death. RESULTS Results show that a set of suicide-related search terms, the trends of which either temporally coincided or preceded trends of suicide data, were associated with suicide death. These search factors varied among different suicide samples. Searches for "major depression" and "divorce" accounted for, at most, 30.2% of the variance in suicide data. When considering only leading suicide trends, searches for "divorce" and the pro-suicide term "complete guide of suicide," accounted for 22.7% of variance in suicide data. CONCLUSIONS Appropriate filtering and detection of potentially harmful source in keyword-driven search results by search engine providers may be a reasonable strategy to reduce suicide deaths.
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Affiliation(s)
- Albert C Yang
- Department of Psychiatry, Chu-Tung Veterans Hospital, Hsin-Chu County, Taiwan.
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Yang AC, Fuh JL, Huang NE, Shia BC, Peng CK, Wang SJ. Temporal associations between weather and headache: analysis by empirical mode decomposition. PLoS One 2011; 6:e14612. [PMID: 21297940 PMCID: PMC3031498 DOI: 10.1371/journal.pone.0014612] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 01/03/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Patients frequently report that weather changes trigger headache or worsen existing headache symptoms. Recently, the method of empirical mode decomposition (EMD) has been used to delineate temporal relationships in certain diseases, and we applied this technique to identify intrinsic weather components associated with headache incidence data derived from a large-scale epidemiological survey of headache in the Greater Taipei area. METHODOLOGY/PRINCIPAL FINDINGS The study sample consisted of 52 randomly selected headache patients. The weather time-series parameters were detrended by the EMD method into a set of embedded oscillatory components, i.e. intrinsic mode functions (IMFs). Multiple linear regression models with forward stepwise methods were used to analyze the temporal associations between weather and headaches. We found no associations between the raw time series of weather variables and headache incidence. For decomposed intrinsic weather IMFs, temperature, sunshine duration, humidity, pressure, and maximal wind speed were associated with headache incidence during the cold period, whereas only maximal wind speed was associated during the warm period. In analyses examining all significant weather variables, IMFs derived from temperature and sunshine duration data accounted for up to 33.3% of the variance in headache incidence during the cold period. The association of headache incidence and weather IMFs in the cold period coincided with the cold fronts. CONCLUSIONS/SIGNIFICANCE Using EMD analysis, we found a significant association between headache and intrinsic weather components, which was not detected by direct comparisons of raw weather data. Contributing weather parameters may vary in different geographic regions and different seasons.
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Affiliation(s)
- Albert C. Yang
- Department of Psychiatry, Chu-Tung Veterans Hospital, Hsin-Chu County, Taiwan
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan
| | - Jong-Ling Fuh
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Norden E. Huang
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan
- Research Center for Adaptive Data Analysis, National Central University, Chungli, Taiwan
| | - Ben-Chang Shia
- Department of Statistics and Information Science, Fu Jen Catholic University, Taipei County, Taiwan
| | - Chung-Kang Peng
- Center for Dynamical Biomarkers and Translational Medicine, National Central University, Chungli, Taiwan
- Margret and H. A. Rey Institute for Nonlinear Dynamics in Medicine, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, United States of America
| | - Shuu-Jiun Wang
- Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan
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Yang AC, Huang NE, Peng CK, Tsai SJ. Do seasons have an influence on the incidence of depression? The use of an internet search engine query data as a proxy of human affect. PLoS One 2010; 5:e13728. [PMID: 21060851 PMCID: PMC2965678 DOI: 10.1371/journal.pone.0013728] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 10/01/2010] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Seasonal depression has generated considerable clinical interest in recent years. Despite a common belief that people in higher latitudes are more vulnerable to low mood during the winter, it has never been demonstrated that human's moods are subject to seasonal change on a global scale. The aim of this study was to investigate large-scale seasonal patterns of depression using Internet search query data as a signature and proxy of human affect. METHODOLOGY/PRINCIPAL FINDINGS Our study was based on a publicly available search engine database, Google Insights for Search, which provides time series data of weekly search trends from January 1, 2004 to June 30, 2009. We applied an empirical mode decomposition method to isolate seasonal components of health-related search trends of depression in 54 geographic areas worldwide. We identified a seasonal trend of depression that was opposite between the northern and southern hemispheres; this trend was significantly correlated with seasonal oscillations of temperature (USA: r = -0.872, p<0.001; Australia: r = -0.656, p<0.001). Based on analyses of search trends over 54 geological locations worldwide, we found that the degree of correlation between searching for depression and temperature was latitude-dependent (northern hemisphere: r = -0.686; p<0.001; southern hemisphere: r = 0.871; p<0.0001). CONCLUSIONS/SIGNIFICANCE Our findings indicate that Internet searches for depression from people in higher latitudes are more vulnerable to seasonal change, whereas this phenomenon is obscured in tropical areas. This phenomenon exists universally across countries, regardless of language. This study provides novel, Internet-based evidence for the epidemiology of seasonal depression.
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Affiliation(s)
- Albert C Yang
- Department of Psychiatry, Chu-Tung Veterans Hospital, Jhudong Township, Taiwan.
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Wu LC, Chen HH, Horng JT, Lin C, Huang NE, Cheng YC, Cheng KF. A novel preprocessing method using Hilbert Huang Transform for MALDI-TOF and SELDI-TOF mass spectrometry data. PLoS One 2010; 5:e12493. [PMID: 20824164 PMCID: PMC2930864 DOI: 10.1371/journal.pone.0012493] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 08/05/2010] [Indexed: 11/27/2022] Open
Abstract
Motivation Mass spectrometry is a high throughput, fast, and accurate method of protein analysis. Using the peaks detected in spectra, we can compare a normal group with a disease group. However, the spectrum is complicated by scale shifting and is also full of noise. Such shifting makes the spectra non-stationary and need to align before comparison. Consequently, the preprocessing of the mass data plays an important role during the analysis process. Noises in mass spectrometry data come in lots of different aspects and frequencies. A powerful data preprocessing method is needed for removing large amount of noises in mass spectrometry data. Results Hilbert-Huang Transformation is a non-stationary transformation used in signal processing. We provide a novel algorithm for preprocessing that can deal with MALDI and SELDI spectra. We use the Hilbert-Huang Transformation to decompose the spectrum and filter-out the very high frequencies and very low frequencies signal. We think the noise in mass spectrometry comes from many sources and some of the noises can be removed by analysis of signal frequence domain. Since the protein in the spectrum is expected to be a unique peak, its frequence domain should be in the middle part of frequence domain and will not be removed. The results show that HHT, when used for preprocessing, is generally better than other preprocessing methods. The approach not only is able to detect peaks successfully, but HHT has the advantage of denoising spectra efficiently, especially when the data is complex. The drawback of HHT is that this approach takes much longer for the processing than the wavlet and traditional methods. However, the processing time is still manageable and is worth the wait to obtain high quality data.
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Affiliation(s)
- Li-Ching Wu
- Graduate Institute of System Biology and Bioinformatics, National Central University, Jhongli, Taiwan.
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Tsui PH, Chang CC, Ho MC, Lee YH, Chen YS, Chang CC, Huang NE, Wu ZH, Chang KJ. Use of nakagami statistics and empirical mode decomposition for ultrasound tissue characterization by a nonfocused transducer. Ultrasound Med Biol 2009; 35:2055-2068. [PMID: 19828227 DOI: 10.1016/j.ultrasmedbio.2009.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 07/08/2009] [Accepted: 08/05/2009] [Indexed: 05/28/2023]
Abstract
The Nakagami parameter associated with the Nakagami distribution estimated from ultrasonic backscattered signals reflects the scatterer concentration in a tissue. A nonfocused transducer does not allow tissue characterization based on the Nakagami parameter. This paper proposes a new method called the noise-assisted Nakagami parameter based on empirical mode decomposition of noisy backscattered echoes to allow quantification of the scatterer concentration based on data obtained using a nonfocused transducer. To explore the practical feasibility of the proposed method, the current study performed experiments on phantoms and measurements on rat livers in vitro with and without fibrosis induction. The results show that using a nonfocused transducer makes it possible to use the noise-assisted Nakagami parameter to classify phantoms with different scatterer concentrations and different stages of liver fibrosis in rats more accurately than when using techniques based on the echo intensity and the conventional Nakagami parameter. However, the conventional Nakagami parameter and the noise-assisted Nakagami parameter have different meanings: the former represents the statistics of signals backscattered from unresolvable scatterers, whereas the latter is associated with stronger resolvable scatterers or local inhomogeneity caused by scatterer aggregation.
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Affiliation(s)
- Po-Hsiang Tsui
- Division of Mechanics, Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan, ROC
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Lin SL, Tung PC, Huang NE. Data analysis using a combination of independent component analysis and empirical mode decomposition. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 79:066705. [PMID: 19658623 DOI: 10.1103/physreve.79.066705] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Indexed: 05/28/2023]
Abstract
A combination of independent component analysis and empirical mode decomposition (ICA-EMD) is proposed in this paper to analyze low signal-to-noise ratio data. The advantages of ICA-EMD combination are these: ICA needs few sensory clues to separate the original source from unwanted noise and EMD can effectively separate the data into its constituting parts. The case studies reported here involve original sources contaminated by white Gaussian noise. The simulation results show that the ICA-EMD combination is an effective data analysis tool.
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Affiliation(s)
- Shih-Lin Lin
- Department of Mechanical Engineering, National Central University, Chungli 320, Taiwan
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Tsui PH, Chang CC, Chang CC, Huang NE, Ho MC. An adaptive threshold filter for ultrasound signal rejection. Ultrasonics 2009; 49:413-418. [PMID: 19056100 DOI: 10.1016/j.ultras.2008.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 10/22/2008] [Accepted: 10/23/2008] [Indexed: 05/27/2023]
Abstract
The threshold filter is a frequently used technique in ultrasound B-scan to reject the small echoes contributed from backscattering that blur the tissue interface and reduce the image contrast. Note that using the threshold based on one value would simultaneously destroy local waveform features of the reflection echoes with amplitudes larger than threshold value. To resolve this problem, we developed an adaptive threshold filter based on the noise-assisted empirical mode decomposition (EMD). Computer simulations at 7.5 MHz using a single-element transducer with a bandwidth of 60% and a pulselength of 0.5 micros were carried out to explore the feasibility of the algorithm. Image measurements on the carotid artery using a 7.5 MHz, 128 elements, 1D linear array transducer with the same characteristics as those in simulations were used to verify the performance of the algorithm in practice. Compared to the result from the conventional threshold technique, the adaptive threshold filter is able to successfully suppress the smaller backscattering signals without changing the local waveform features of the preserved significant echoes due to reflection.
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Affiliation(s)
- Po-Hsiang Tsui
- Division of Mechanics, Research Center for Applied Sciences, Academia Sinica 128, Section 2, Academia Road, Nankang, Taipei 11529, Taiwan, ROC
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Hu K, Peng C, Huang NE, Wu Z, Lipsitz LA, Cavallerano J, Novak V. Altered Phase Interactions between Spontaneous Blood Pressure and Flow Fluctuations in Type 2 Diabetes Mellitus: Nonlinear Assessment of Cerebral Autoregulation. Physica A 2008; 387:2279-2292. [PMID: 18432311 PMCID: PMC2329796 DOI: 10.1016/j.physa.2007.11.052] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Cerebral autoregulation (CA) is an important mechanism that involves dilation and constriction in arterioles to maintain relatively s cerebral blood flow in response to changes of systemic blood pressure. Traditional assessments of CA focus on the changes of cerebral blood flow velocity in response to large blood pressure fluctuations induced by interventions. This approach is not feasible for patients with impaired autoregulation or cardiovascular regulation. Here we propose a newly developed technique-the multimodal pressure-flow (MMPF) analysis, which assesses CA by quantifying nonlinear phase interactions between spontaneous oscillations in blood pressure and flow velocity during resting conditions. We show that CA in healthy subjects can be characterized by specific phase shifts between spontaneous blood pressure and flow velocity oscillations, and the phase shifts are significantly reduced in diabetic subjects. Smaller phase shifts between oscillations in the two variables indicate more passive dependence of blood flow velocity on blood pressure, thus suggesting impaired cerebral autoregulation. Moreover, the reduction of the phase shifts in diabetes is observed not only in previously-recognized effective region of CA (<0.1Hz), but also over the higher frequency range from ~0.1 to 0.4Hz. These findings indicate that Type 2 diabetes alters cerebral blood flow regulation over a wide frequency range and that this alteration can be reliably assessed from spontaneous oscillations in blood pressure and blood flow velocity during resting conditions. We also show that the MMPF method has better performance than traditional approaches based on Fourier transform, and is more sui for the quantification of nonlinear phase interactions between nonstationary biological signals such as blood pressure and blood flow.
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Affiliation(s)
- Kun Hu
- Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - C.K. Peng
- Division of Interdisciplinary Medicine & Biotechnology and Margret and H.A. Rey Institute for Nonlinear Dynamics in Medicine, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA
| | - Norden E. Huang
- Research Center for Data Analysis, National Central University, Chungli, Taiwan, ROC
| | - Zhaohua Wu
- Center for Ocean-Land-Atmosphere Studies, Calverton, Maryland
| | - Lewis A. Lipsitz
- Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
- Hebrew SeniorLife, Boston MA
| | | | - Vera Novak
- Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
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Abstract
Determining trend and implementing detrending operations are important steps in data analysis. Yet there is no precise definition of "trend" nor any logical algorithm for extracting it. As a result, various ad hoc extrinsic methods have been used to determine trend and to facilitate a detrending operation. In this article, a simple and logical definition of trend is given for any nonlinear and nonstationary time series as an intrinsically determined monotonic function within a certain temporal span (most often that of the data span), or a function in which there can be at most one extremum within that temporal span. Being intrinsic, the method to derive the trend has to be adaptive. This definition of trend also presumes the existence of a natural time scale. All these requirements suggest the Empirical Mode Decomposition (EMD) method as the logical choice of algorithm for extracting various trends from a data set. Once the trend is determined, the corresponding detrending operation can be implemented. With this definition of trend, the variability of the data on various time scales also can be derived naturally. Climate data are used to illustrate the determination of the intrinsic trend and natural variability.
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Affiliation(s)
- Zhaohua Wu
- Center for Ocean-Land-Atmosphere Studies, 4041 Powder Mill Road, Suite 302, Calverton, MD 20705, USA.
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Costa M, Priplata AA, Lipsitz LA, Wu Z, Huang NE, Goldberger AL, Peng CK. Noise and poise: Enhancement of postural complexity in the elderly with a stochastic-resonance-based therapy. Europhys Lett 2007; 77:68008. [PMID: 17710211 PMCID: PMC1949396 DOI: 10.1209/0295-5075/77/68008] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Pathologic states are associated with a loss of dynamical complexity. Therefore, therapeutic interventions that increase physiologic complexity may enhance health status. Using multiscale entropy analysis, we show that the postural sway dynamics of healthy young and healthy elderly subjects are more complex than that of elderly subjects with a history of falls. Application of subsensory noise to the feet has been demonstrated to improve postural stability in the elderly. We next show that this therapy significantly increases the multiscale complexity of sway fluctuations in healthy elderly subjects. Quantification of changes in dynamical complexity of biologic variability may be the basis of a new approach to assessing risk and to predicting the efficacy of clinical interventions, including noise-based therapies.
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Affiliation(s)
- M Costa
- Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center, Harvard Medical School - 330 Brookline Avenue, Boston, MA 02215, USA
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Affiliation(s)
- Zhaohua Wu
- Center for Ocean-Land-Atmosphere Studies, 4041 Powder Mill Road, Suite 302, Calverton, MD 20705, USA
| | - Norden E. Huang
- Goddard Institute for Data Analysis, Code 614.2, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
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Affiliation(s)
- Norden E. Huang
- Goddard Institute for Data Analysis, Code 614.2, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
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Affiliation(s)
- Zhaohua Wu
- Center for Ocean-Land-Atmosphere Studies, Suite 302, 4041 Powder Mill Road, Calverton, MD 20705, USA
| | - Norden E. Huang
- Laboratory for Hydrospheric Processes/Oceans and Ice Branch, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
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Zheng Q, Clemente-Colón P, Yan XH, Liu WT, Huang NE. Satellite synthetic aperture radar detection of Delaware Bay plumes: Jet-like feature analysis. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jc002100] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Quanan Zheng
- Department of Meteorology; University of Maryland; College Park Maryland USA
| | | | - Xiao-Hai Yan
- College of Marine Studies; University of Delaware; Newark Delaware USA
| | - W. Timothy Liu
- Jet Propulsion Laboratory 300-323; California Institute of Technology; Pasadena California USA
| | - Norden E. Huang
- Ocean and Ice Branch; NASA Goddard Space Flight Center; Greenbelt Maryland USA
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Cummings DAT, Irizarry RA, Huang NE, Endy TP, Nisalak A, Ungchusak K, Burke DS. Travelling waves in the occurrence of dengue haemorrhagic fever in Thailand. Nature 2004; 427:344-7. [PMID: 14737166 DOI: 10.1038/nature02225] [Citation(s) in RCA: 362] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Accepted: 11/20/2003] [Indexed: 11/08/2022]
Abstract
Dengue fever is a mosquito-borne virus that infects 50-100 million people each year. Of these infections, 200,000-500,000 occur as the severe, life-threatening form of the disease, dengue haemorrhagic fever (DHF). Large, unanticipated epidemics of DHF often overwhelm health systems. An understanding of the spatial-temporal pattern of DHF incidence would aid the allocation of resources to combat these epidemics. Here we examine the spatial-temporal dynamics of DHF incidence in a data set describing 850,000 infections occurring in 72 provinces of Thailand during the period 1983 to 1997. We use the method of empirical mode decomposition to show the existence of a spatial-temporal travelling wave in the incidence of DHF. We observe this wave in a three-year periodic component of variance, which is thought to reflect host-pathogen population dynamics. The wave emanates from Bangkok, the largest city in Thailand, moving radially at a speed of 148 km per month. This finding provides an important starting point for detecting and characterizing the key processes that contribute to the spatial-temporal dynamics of DHF in Thailand.
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Affiliation(s)
- Derek A T Cummings
- Department of Geography and Environmental Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Huang NE, Wu MLC, Long SR, Shen SS, Qu W, Gloersen P, Fan KL. A confidence limit for the empirical mode decomposition and Hilbert spectral analysis. Proc Math Phys Eng Sci 2003. [DOI: 10.1098/rspa.2003.1123] [Citation(s) in RCA: 858] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Norden E Huang
- 1Code 971, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - Man-Li C Wu
- Code 910, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - Steven R Long
- Code 972, NASA GSFC/Wallops Flight Facility, Wallops Island, VA 23337, USA
| | - Samuel S.P Shen
- Department of Mathematical Sciences, University of Alberta, Edmonton T6G 2G1, Canada
| | - Wendong Qu
- Engineering Sciences, Mail Stop 104–44, California Institute of Technology, Pasadena, CA 91125, USA
| | - Per Gloersen
- 1Code 971, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - Kuang L Fan
- Institute of Oceanography, National Taiwan University, N0. 1, Sec. 4, Roosevelt Road, Taipei POB 23‐13, Tainwan 106, Republic of China
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