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Kausch SL, Sullivan B, Spaeder MC, Keim-Malpass J. Individual illness dynamics: An analysis of children with sepsis admitted to the pediatric intensive care unit. PLOS DIGITAL HEALTH 2022; 1:e0000019. [PMID: 36812513 PMCID: PMC9931234 DOI: 10.1371/journal.pdig.0000019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 01/30/2022] [Indexed: 12/16/2022]
Abstract
Illness dynamics and patterns of recovery may be essential features in understanding the critical illness course. We propose a method to characterize individual illness dynamics in patients who experienced sepsis in the pediatric intensive care unit. We defined illness states based on illness severity scores generated from a multi-variable prediction model. For each patient, we calculated transition probabilities to characterize movement among illness states. We calculated the Shannon entropy of the transition probabilities. Using the entropy parameter, we determined phenotypes of illness dynamics based on hierarchical clustering. We also examined the association between individual entropy scores and a composite variable of negative outcomes. Entropy-based clustering identified four illness dynamic phenotypes in a cohort of 164 intensive care unit admissions where at least one sepsis event occurred. Compared to the low-risk phenotype, the high-risk phenotype was defined by the highest entropy values and had the most ill patients as defined by a composite variable of negative outcomes. Entropy was significantly associated with the negative outcome composite variable in a regression analysis. Information-theoretical approaches to characterize illness trajectories offer a novel way of assessing the complexity of a course of illness. Characterizing illness dynamics with entropy offers additional information in conjunction with static assessments of illness severity. Additional attention is needed to test and incorporate novel measures representing the dynamics of illness.
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Affiliation(s)
- Sherry L. Kausch
- University of Virginia School of Nursing, Charlottesville, VA, United States of America
- Center for Advanced Medical Analytics, University of Virginia, Charlottesville, VA, United States of America
- * E-mail:
| | - Brynne Sullivan
- Center for Advanced Medical Analytics, University of Virginia, Charlottesville, VA, United States of America
- Department of Pediatrics, Division of Neonatology, University of Virginia School of Medicine, Charlottesville, VA, United States of America
| | - Michael C. Spaeder
- Center for Advanced Medical Analytics, University of Virginia, Charlottesville, VA, United States of America
- Department of Pediatrics, Division of Pediatric Critical Care, University of Virginia School of Medicine, Charlottesville, VA, United States of America
| | - Jessica Keim-Malpass
- University of Virginia School of Nursing, Charlottesville, VA, United States of America
- Center for Advanced Medical Analytics, University of Virginia, Charlottesville, VA, United States of America
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2
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Desplats P, Gutierrez AM, Antonelli MC, Frasch MG. Microglial memory of early life stress and inflammation: Susceptibility to neurodegeneration in adulthood. Neurosci Biobehav Rev 2020; 117:232-242. [PMID: 31703966 PMCID: PMC7198341 DOI: 10.1016/j.neubiorev.2019.10.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 09/15/2019] [Accepted: 10/20/2019] [Indexed: 02/08/2023]
Abstract
We review evidence supporting the role of early life programming in the susceptibility for adult neurodegenerative diseases while highlighting questions and proposing avenues for future research to advance our understanding of this fundamental process. The key elements of this phenomenon are chronic stress, neuroinflammation triggering microglial polarization, microglial memory and their connection to neurodegeneration. We review the mediating mechanisms which may function as early biomarkers of increased susceptibility for neurodegeneration. Can we devise novel early life modifying interventions to steer developmental trajectories to their optimum?
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Affiliation(s)
- Paula Desplats
- Department of Neurosciences, University of California San Diego, CA, USA; Department of Pathology, University of California San Diego, CA, USA
| | - Ashley M Gutierrez
- Department of Neurosciences, University of California San Diego, CA, USA
| | - Marta C Antonelli
- Instituto de Biología Celular y Neurociencia "Prof. Eduardo De Robertis", Facultad de Medicina, Universidad de Buenos Aires, Argentina; Department of Obstetrics and Gynecology, Klinikum rechts der Isar, Technical University of Munich, Germany
| | - Martin G Frasch
- Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, USA; Center on Human Development and Disability, University of Washington, Seattle, WA, USA.
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Complexity-Based Measures of Heart Rate Dynamics in Older Adults Following Long- and Short-Term Tai Chi Training: Cross-sectional and Randomized Trial Studies. Sci Rep 2019; 9:7500. [PMID: 31097732 PMCID: PMC6522618 DOI: 10.1038/s41598-019-43602-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 04/27/2019] [Indexed: 12/19/2022] Open
Abstract
Measures characterizing the complexity of heart rate (HR) dynamics have been informative in predicting age- and disease-related decline in cardiovascular health, but few studies have evaluated whether mind-body exercise can impact HR complexity. This study evaluated the effects of long-term Tai Chi (TC) practice on the complexity of HR dynamics using an observational comparison of TC experts and age- and gender-matched TC-naïve individuals. Shorter-term effects of TC were assessed by randomly assigning TC-naïve participants to either TC group to receive six months of TC training or to a waitlist control group. 23 TC experts (age = 63.3 ± 8.0 y; 24.6 ± 12.0 y TC experience) and 52 TC-naïve (age = 64.3 ± 7.7 y) were enrolled. In cross-sectional analyses, TC experts had a higher overall complexity index (CI, p = 0.004) and higher entropy at multiple individual time scales (p < 0.05); these findings persisted in models accounting for age, gender, body mass index (BMI), and physical activity levels. Longitudinal changes in complexity index did not differ significantly following random assignment to six months of TC vs. a waitlist control; however, within the TC group, complexity at select time scales showed statistically non-significant trends toward increases. Our study supports that longer-term TC mind-body training may be associated with increased complexity of HR dynamics.
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Scholkmann F, Wolf U. The Pulse-Respiration Quotient: A Powerful but Untapped Parameter for Modern Studies About Human Physiology and Pathophysiology. Front Physiol 2019; 10:371. [PMID: 31024336 PMCID: PMC6465339 DOI: 10.3389/fphys.2019.00371] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 03/18/2019] [Indexed: 01/06/2023] Open
Abstract
A specific and unique aspect of cardiorespiratory activity can be captured by dividing the heart rate (HR) by the respiration rate (RR), giving the pulse-respiration quotient (PRQ = HR/RR). In this review article, we summarize the main findings of studies using and investigating the PRQ. We describe why the PRQ is a powerful parameter that captures complex regulatory states of the cardiorespiratory system, and we highlight the need to re-introduce the use of this parameter into modern studies about human physiology and pathophysiology. In particular, we show that the PRQ (i) changes during human development, (ii) is time-dependent (ultradian, circadian, and infradian rhythms), (iii) shows specific patterns during sleep, (iv) changes with physical activity and body posture, (v) is linked with psychophysical and cognitive activity, (vi) is sex-dependent, and (vii) is determined by the individual physiological constitution. Furthermore, we discuss the medical aspects of the PRQ in terms of applications for disease classification and monitoring. Finally, we explain why there should be a revival in the use of the PRQ for basic research about human physiology and for applications in medicine, and we give recommendations for the use of the PRQ in studies and medical applications.
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Affiliation(s)
- Felix Scholkmann
- Institute of Complementary and Integrative Medicine, University of Bern, Bern, Switzerland
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Lucchini M, Pini N, Fifer WP, Burtchen N, Signorini MG. Characterization of cardiorespiratory phase synchronization and directionality in late premature and full term infants. Physiol Meas 2018; 39:064001. [PMID: 29767630 PMCID: PMC6063316 DOI: 10.1088/1361-6579/aac553] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Though the mutual influence of cardiovascular and respiratory rhythms in healthy newborns has been documented, its full characterization is still pending. In general, the activity of many physiological subsystems has a well-expressed rhythmic character, and often an interdependency between physiological rhythms emerges early in development. Traditional methods of data analysis only address the quantification of the strength of subsystem interactions. In this work, we will investigate system interrelationships in terms of the possible presence of causal or directional interplays. APPROACH In this paper, we propose a methodological application that quantifies phase coupling and its directionality in a population of newborn infants born between 35 and 40 weeks of gestational age (GA). The aim is to assess whether GA at birth significantly influences the development of phase synchronization and the directionality of the coupling between the cardiovascular and respiratory system activity. Several studies indicating irregular cardiorespiratory coupling as a leading cause of several pathologies underscore the need to investigate this phenomenon in this at-risk population. MAIN RESULTS Results from our investigation show a different directionality profile as a function of GA and sleep state. SIGNIFICANCE These findings are a contribution to the understanding of higher risk for the documented negative outcomes in the late preterm population. Moreover, these parameters could provide a tool for the development of early markers of cardiorespiratory dysregulation in infants.
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Affiliation(s)
- Maristella Lucchini
- Department of Psychiatry, Columbia University College of Physicians & Surgeons, New York, NY, United States of America. Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milano, Italy
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Roebuck A, Monasterio V, Gederi E, Osipov M, Behar J, Malhotra A, Penzel T, Clifford GD. A review of signals used in sleep analysis. Physiol Meas 2014; 35:R1-57. [PMID: 24346125 PMCID: PMC4024062 DOI: 10.1088/0967-3334/35/1/r1] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This article presents a review of signals used for measuring physiology and activity during sleep and techniques for extracting information from these signals. We examine both clinical needs and biomedical signal processing approaches across a range of sensor types. Issues with recording and analysing the signals are discussed, together with their applicability to various clinical disorders. Both univariate and data fusion (exploiting the diverse characteristics of the primary recorded signals) approaches are discussed, together with a comparison of automated methods for analysing sleep.
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Affiliation(s)
- A Roebuck
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, UK
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Phase Synchronization Analysis of EEG Signals: An Evaluation Based on Surrogate Tests. IEEE Trans Biomed Eng 2012; 59:2254-63. [PMID: 22665500 DOI: 10.1109/tbme.2012.2199490] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Larsen P, Tzeng Y, Sin P, Galletly D. Respiratory sinus arrhythmia in conscious humans during spontaneous respiration. Respir Physiol Neurobiol 2010; 174:111-8. [DOI: 10.1016/j.resp.2010.04.021] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 04/19/2010] [Accepted: 04/19/2010] [Indexed: 10/19/2022]
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McAllister R, Meucci R, DeShazer D, Roy R. Competition between two frequencies for phase synchronization of a chaotic laser. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:015202. [PMID: 12636548 DOI: 10.1103/physreve.67.015202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2002] [Indexed: 05/24/2023]
Abstract
Competition between two distinct driving frequencies to phase synchronize the intensity dynamics of a chaotic laser has been observed. The phase of the chaotic intensity signal is constructed using the complex analytic signal. Competing frequencies alternately show phase locking and phase slipping. Competition has been quantified by calculating the portion of time the laser phase locks to each of the driving frequencies and their average.
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Affiliation(s)
- Ryan McAllister
- Department of Physics, University of Maryland, College Park, Maryland 20742, USA
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Bettermann H, Cysarz D, Van Leeuwen P. Comparison of two different approaches in the detection of intermittent cardiorespiratory coordination during night sleep. BMC PHYSIOLOGY 2002; 2:18. [PMID: 12464159 PMCID: PMC140027 DOI: 10.1186/1472-6793-2-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2002] [Accepted: 12/04/2002] [Indexed: 11/25/2022]
Abstract
BACKGROUND The objective was to evaluate and to compare two completely different detection algorithms of intermittent (short-term) cardiorespiratory coordination during night sleep. The first method is based on a combination of respiratory flow and electrocardiogram recordings and determines the relative phases of R waves between successive onsets of inspiration. Intermittent phase coordination is defined as phase recurrence with accuracy alpha over at least k heartbeats. The second, recently introduced method utilizes only binary coded variations of heart rate (acceleration = 1, deceleration = 0) and identifies binary pattern classes which can be assigned to respiratory sinus arrhythmia (RSA). It is hypothesized that RSA pattern class recurrence over at least k heartbeats is strongly related with the intermittent phase coordination defined above. RESULTS Both methods were applied to night time recordings of 20 healthy subjects. In subjects <45 yrs and setting k = 3 and alpha = 0.03, the phase and RSA pattern recurrence were highly correlated. Furthermore, in most subjects the pattern predominance (PP) showed a pronounced oscillation which is most likely linked with the dynamics of sleep stages. However, the analysis of bivariate variation and the use of surrogate data suggest that short-term phase coordination mainly resulted from central adjustment of heart rate and respiratory rate rather than from real phase synchronization due to physiological interaction. CONCLUSION Binary pattern analysis provides essential information on short-term phase recurrence and reflects nighttime sleep architecture, but is only weakly linked with true phase synchronization which is rare in physiological processes of man.
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Affiliation(s)
- Henrik Bettermann
- Department of Clinical Research, Gemeinschaftskrankenhaus, 58313 Herdecke, Germany
| | - Dirk Cysarz
- Department of Clinical Research, Gemeinschaftskrankenhaus, 58313 Herdecke, Germany
| | - Peter Van Leeuwen
- Research and Development Center for Microtherapy, 44799 Bochum, Germany
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Hoyer D, Leder U, Hoyer H, Pompe B, Sommer M, Zwiener U. Mutual information and phase dependencies: measures of reduced nonlinear cardiorespiratory interactions after myocardial infarction. Med Eng Phys 2002; 24:33-43. [PMID: 11891138 DOI: 10.1016/s1350-4533(01)00120-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The heart rate variability (HRV) is related to several mechanisms of the complex autonomic functioning such as respiratory heart rate modulation and phase dependencies between heart beat cycles and breathing cycles. The underlying processes are basically nonlinear. In order to understand and quantitatively assess those physiological interactions an adequate coupling analysis is necessary. We hypothesized that nonlinear measures of HRV and cardiorespiratory interdependencies are superior to the standard HRV measures in classifying patients after acute myocardial infarction. We introduced mutual information measures which provide access to nonlinear interdependencies as counterpart to the classically linear correlation analysis. The nonlinear statistical autodependencies of HRV were quantified by auto mutual information, the respiratory heart rate modulation by cardiorespiratory cross mutual information, respectively. The phase interdependencies between heart beat cycles and breathing cycles were assessed basing on the histograms of the frequency ratios of the instantaneous heart beat and respiratory cycles. Furthermore, the relative duration of phase synchronized intervals was acquired. We investigated 39 patients after acute myocardial infarction versus 24 controls. The discrimination of these groups was improved by cardiorespiratory cross mutual information measures and phase interdependencies measures in comparison to the linear standard HRV measures. This result was statistically confirmed by means of logistic regression models of particular variable subsets and their receiver operating characteristics.
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Affiliation(s)
- Dirk Hoyer
- Institute for Pathophysiology, Friedrich Schiller University, 07740 Jena, Germany.
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Abstract
The sympathetic-parasympathetic balance may be altered in critically ill patients. Assessment of autonomic function provides information concerning prognosis, pathogenesis, and treatment strategies in ICU-relevant disorders. Proven tools are heart rate variability, baroreflex sensitivity, and, with limitations, cardiac chemoreflex sensitivity. New nonlinear methods are being evaluated that may predict risk more precisely in critically ill patients. This article summarizes application of these tools in the ICU. In addition, a model is introduced for investigating the impaired autonomic function in multiple organ dysfunction syndrome and sepsis, integrating extrinsic mechanisms and factors that are intrinsic to the cardiac tissue. By this combined approach, the authors hope to gain insight into the pathogenesis of multiple organ dysfunction syndrome. New pathophysiologic concepts are needed for the development of treatment strategies for this life-threatening disease.
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Affiliation(s)
- H B Schmidt
- Department of Medicine 111, Martin-Luther-University Halle-Wittenberg, Klinikum Kröllwitz, Germany
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