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Quigley KS, Gianaros PJ, Norman GJ, Jennings JR, Berntson GG, de Geus EJC. Publication guidelines for human heart rate and heart rate variability studies in psychophysiology-Part 1: Physiological underpinnings and foundations of measurement. Psychophysiology 2024:e14604. [PMID: 38873876 DOI: 10.1111/psyp.14604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 12/22/2023] [Accepted: 04/04/2024] [Indexed: 06/15/2024]
Abstract
This Committee Report provides methodological, interpretive, and reporting guidance for researchers who use measures of heart rate (HR) and heart rate variability (HRV) in psychophysiological research. We provide brief summaries of best practices in measuring HR and HRV via electrocardiographic and photoplethysmographic signals in laboratory, field (ambulatory), and brain-imaging contexts to address research questions incorporating measures of HR and HRV. The Report emphasizes evidence for the strengths and weaknesses of different recording and derivation methods for measures of HR and HRV. Along with this guidance, the Report reviews what is known about the origin of the heartbeat and its neural control, including factors that produce and influence HRV metrics. The Report concludes with checklists to guide authors in study design and analysis considerations, as well as guidance on the reporting of key methodological details and characteristics of the samples under study. It is expected that rigorous and transparent recording and reporting of HR and HRV measures will strengthen inferences across the many applications of these metrics in psychophysiology. The prior Committee Reports on HR and HRV are several decades old. Since their appearance, technologies for human cardiac and vascular monitoring in laboratory and daily life (i.e., ambulatory) contexts have greatly expanded. This Committee Report was prepared for the Society for Psychophysiological Research to provide updated methodological and interpretive guidance, as well as to summarize best practices for reporting HR and HRV studies in humans.
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Affiliation(s)
- Karen S Quigley
- Department of Psychology, Northeastern University, Boston, Massachusetts, USA
| | - Peter J Gianaros
- Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Greg J Norman
- Department of Psychology, The University of Chicago, Chicago, Illinois, USA
| | - J Richard Jennings
- Department of Psychiatry & Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Gary G Berntson
- Department of Psychology & Psychiatry, The Ohio State University, Columbus, Ohio, USA
| | - Eco J C de Geus
- Department of Biological Psychology, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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Neerland BE, Wyller TB, Wyller VBB. Autonomic cardiovascular control in older patients with acute infection and delirium: a pilot study of orthostatic stress responses. BMC Geriatr 2019; 19:23. [PMID: 30683068 PMCID: PMC6347784 DOI: 10.1186/s12877-019-1035-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/14/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Alterations in autonomic nervous system (ANS) activity might be involved in the pathophysiology of delirium. The aim was to explore autonomic cardiovascular control in older patients with and without delirium. METHODS Fourteen patients (five with delirium) acutely admitted to the geriatric ward with an infection were enrolled in the study. Patients with atrial fibrillation, a pacemaker, or on treatment with beta-blockers, calcium channel blockers or acetylcholinesterase inhibitors were not eligible. Continuous, non-invasive hemodynamic variables were measured during supine rest (5 min) and head-up tilt (HUT) to 15 degrees (10 min). Heart rate (HR), blood pressure (BP) and stroke volume (SV) were recorded beat-to-beat. Cardiac output (CO), total peripheral resistance (TPR), end-diastolic volume (EDV) and heart rate variability (HRV) values were calculated. RESULTS Median age was 86 years. HR, BP, SV, CO, TPR and EDV were similar across the two groups at rest, but there was a trend towards a greater increase in systolic BP and HR during HUT in the delirium group. At rest, all HRV indices were higher in the delirium group, but the differences were not statistically significant. During HUT, the delirium group had higher power spectral density (PSD) (representing total variability) (p = 0.06) and a lower low frequency (LF)/high frequency (HF)-ratio (an index of sympathovagal balance) than the control group (p = 0.06). Also, delirious patients had a significantly greater reduction in standard deviation of RR-intervals (SDNN) (representing total variability) from baseline than controls (p = 0.01) during HUT. CONCLUSIONS This explorative pilot study on autonomic cardiovascular control in delirium suggests that there may be differences in HRV that should be further investigated in larger samples.
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Affiliation(s)
- Bjørn Erik Neerland
- Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Oslo Delirium Research Group, Department of Geriatric Medicine, University of Oslo, P.O.BOX 4956, Nydalen, N-0424 Oslo, Norway
| | - Torgeir Bruun Wyller
- Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Oslo Delirium Research Group, Department of Geriatric Medicine, University of Oslo, P.O.BOX 4956, Nydalen, N-0424 Oslo, Norway
| | - Vegard Bruun Bratholm Wyller
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Pediatrics, Akershus University Hospital, Lørenskog, Norway
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Times Varying Spectral Coherence Investigation of Cardiovascular Signals Based on Energy Concentration in Healthy Young and Elderly Subjects by the Adaptive Continuous Morlet Wavelet Transform. Ing Rech Biomed 2018. [DOI: 10.1016/j.irbm.2017.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Khaleel M, Puliyel M, Shah P, Sunwoo J, Kato RM, Chalacheva P, Thuptimdang W, Detterich J, Wood JC, Tsao J, Zeltzer L, Sposto R, Khoo MCK, Coates TD. Individuals with sickle cell disease have a significantly greater vasoconstriction response to thermal pain than controls and have significant vasoconstriction in response to anticipation of pain. Am J Hematol 2017; 92:1137-1145. [PMID: 28707371 DOI: 10.1002/ajh.24858] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 12/17/2022]
Abstract
The painful vaso-occlusive crises (VOC) that characterize sickle cell disease (SCD) progress over hours from the asymptomatic steady-state. SCD patients report that VOC can be triggered by stress, cold exposure, and, pain itself. We anticipated that pain could cause neural-mediated vasoconstriction, decreasing regional blood flow and promoting entrapment of sickle cells in the microvasculature. Therefore, we measured microvascular blood flow in the fingers of both hands using plethysmography and laser-Doppler flowmetry while applying a series of painful thermal stimuli on the right forearm in 23 SCD patients and 25 controls. Heat pain applied to one arm caused bilateral decrease in microvascular perfusion. The vasoconstriction response started before administration of the thermal pain stimulus in all subjects, suggesting that pain anticipation also causes significant vasoconstriction. The time delay between thermal pain application and global vasoconstriction ranged from 5 to 15.5 seconds and increased with age (P < .01). Although subjective measures, pain threshold and pain tolerance were not different between SCD subjects and controls, but the vaso-reactivity index characterizing the microvascular blood flow response to painful stimuli was significantly higher in SCD patients (P = .0028). This global vasoconstriction increases microvascular transit time, and may promote entrapment of sickle cells in the microvasculature, making vaso-occlusion more likely. The rapidity of the global vasoconstriction response indicates a neural origin that may play a part in the transition from steady-state to VOC, and may also contribute to the variability in VOC frequency observed in SCD patients.
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Affiliation(s)
- Maha Khaleel
- Section of Hematology; Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
| | - Mammen Puliyel
- Section of Hematology; Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
| | - Payal Shah
- Section of Hematology; Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
| | - John Sunwoo
- Biomedical engineering; Viterbi School of Engineering; Los Angeles California
| | - Roberta M. Kato
- Division of Pulmonology; Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
| | | | - Wanwara Thuptimdang
- Biomedical engineering; Viterbi School of Engineering; Los Angeles California
| | - Jon Detterich
- Division of Cardiology; Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
| | - John C. Wood
- Biomedical engineering; Viterbi School of Engineering; Los Angeles California
- Division of Cardiology; Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
| | - Jennie Tsao
- Pediatric Pain Program, University of California Los Angeles; Los Angeles California
| | - Lonnie Zeltzer
- Pediatric Pain Program, University of California Los Angeles; Los Angeles California
| | - Richard Sposto
- Section of Hematology; Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
- Department of Preventive Medicine, Keck School of Medicine; University of Southern California; Los Angeles California
| | - Michael C. K. Khoo
- Biomedical engineering; Viterbi School of Engineering; Los Angeles California
| | - Thomas D. Coates
- Section of Hematology; Children's Center for Cancer and Blood Diseases, Children's Hospital Los Angeles, Keck School of Medicine; Los Angeles California
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Methods of assessment of the post-exercise cardiac autonomic recovery: A methodological review. Int J Cardiol 2017; 227:795-802. [DOI: 10.1016/j.ijcard.2016.10.057] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/18/2016] [Accepted: 10/22/2016] [Indexed: 11/23/2022]
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Hilz MJ, Liu M, Koehn J, Wang R, Ammon F, Flanagan SR, Hösl KM. Valsalva maneuver unveils central baroreflex dysfunction with altered blood pressure control in persons with a history of mild traumatic brain injury. BMC Neurol 2016; 16:61. [PMID: 27146718 PMCID: PMC4857428 DOI: 10.1186/s12883-016-0584-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Accepted: 04/29/2016] [Indexed: 02/04/2023] Open
Abstract
Background Patients with a history of mild TBI (post-mTBI-patients) have an unexplained increase in long-term mortality which might be related to central autonomic dysregulation (CAD). We investigated whether standardized baroreflex-loading, induced by a Valsalva maneuver (VM), unveils CAD in otherwise healthy post-mTBI-patients. Methods In 29 healthy persons (31.3 ± 12.2 years; 9 women) and 25 post-mTBI-patients (35.0 ± 13.2 years, 7 women, 4–98 months post-injury), we monitored respiration (RESP), RR-intervals (RRI) and systolic blood pressure (BP) at rest and during three VMs. At rest, we calculated parameters of total autonomic modulation [RRI-coefficient-of-variation (CV), RRI-standard-deviation (RRI-SD), RRI-total-powers], of sympathetic [RRI-low-frequency-powers (LF), BP-LF-powers] and parasympathetic modulation [square-root-of-mean-squared-differences-of-successive-RRIs (RMSSD), RRI-high-frequency-powers (HF)], the index of sympatho-vagal balance (RRI LF/HF-ratios), and baroreflex sensitivity (BRS). We calculated Valsalva-ratios (VR) and times from lowest to highest RRIs after strain (VR-time) as indices of parasympathetic activation, intervals from highest systolic BP-values after strain-release to the time when systolic BP had fallen by 90 % of the differences between peak-phase-IV-BP and baseline-BP (90 %-BP-normalization-times), and velocities of BP-normalization (90 %-BP-normalization-velocities) as indices of sympathetic withdrawal. We compared patient- and control-parameters before and during VM (Mann-Whitney-U-tests or t-tests; significance: P < 0.05). Results At rest, RRI-CVs, RRI-SDs, RRI-total-powers, RRI-LF-powers, BP-LF-powers, RRI-RMSSDs, RRI-HF-powers, and BRS were lower in patients than controls. During VMs, 90 %-BP-normalization-times were longer, and 90 %-BP-normalization-velocities were lower in patients than controls (P < 0.05). Conclusions Reduced autonomic modulation at rest and delayed BP-decrease after VM-induced baroreflex-loading indicate subtle CAD with altered baroreflex adjustment to challenge. More severe autonomic challenge might trigger more prominent cardiovascular dysregulation and thus contribute to increased mortality risk in post-mTBI-patients.
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Affiliation(s)
- Max J Hilz
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054, Erlangen, Germany.
| | - Mao Liu
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054, Erlangen, Germany
| | - Julia Koehn
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054, Erlangen, Germany
| | - Ruihao Wang
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054, Erlangen, Germany
| | - Fabian Ammon
- Department of Neurology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054, Erlangen, Germany
| | - Steven R Flanagan
- Department of Rehabilitation Medicine, New York University School of Medicine, 240 East 38th Street, New York, NY, 10016, USA
| | - Katharina M Hösl
- Department of Psychiatry and Psychotherapy, Paracelsus Medical University Nuremberg, Prof.-Ernst-Nathan-Strasse 1, 90419, Nuremberg, Germany
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Music induces different cardiac autonomic arousal effects in young and older persons. Auton Neurosci 2014; 183:83-93. [DOI: 10.1016/j.autneu.2014.02.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 02/13/2014] [Accepted: 02/18/2014] [Indexed: 11/24/2022]
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Daoud M, Ravier P, Harba R, Jabloun M, Yagoubi B, Buttelli O. HRV spectral estimation based on constrained Gaussian modeling in the nonstationary case. Biomed Signal Process Control 2013. [DOI: 10.1016/j.bspc.2013.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Sangkatumvong S, Khoo MCK, Kato R, Detterich JA, Bush A, Keens TG, Meiselman HJ, Wood JC, Coates TD. Peripheral vasoconstriction and abnormal parasympathetic response to sighs and transient hypoxia in sickle cell disease. Am J Respir Crit Care Med 2011; 184:474-81. [PMID: 21616995 DOI: 10.1164/rccm.201103-0537oc] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
RATIONALE Sickle cell disease is an inherited blood disorder characterized by vasoocclusive crises. Although hypoxia and pulmonary disease are known risk factors for these crises, the mechanisms that initiate vasoocclusive events are not well known. OBJECTIVES To study the relationship between transient hypoxia, respiration, and microvascular blood flow in patients with sickle cell. METHODS We established a protocol that mimics nighttime hypoxic episodes and measured microvascular blood flow to determine if transient hypoxia causes a decrease in microvascular blood flow. Significant desaturations were induced safely by five breaths of 100% nitrogen. MEASUREMENTS AND MAIN RESULTS Desaturation did not induce change in microvascular perfusion; however, it induced substantial transient parasympathetic activity withdrawal in patients with sickle cell disease, but not controls subjects. Marked periodic drops in peripheral microvascular perfusion, unrelated to hypoxia, were triggered by sighs in 11 of 11 patients with sickle cell and 8 of 11 control subjects. Although the sigh frequency was the same in both groups, the probability of a sigh inducing a perfusion drop was 78% in patients with sickle cell and 17% in control subjects (P < 0.001). Evidence for sigh-induced sympathetic nervous system dominance was seen in patients with sickle cell (P < 0.05), but was not significant in control subjects. CONCLUSIONS These data demonstrate significant disruption of autonomic nervous system balance, with marked parasympathetic withdrawal in response to transient hypoxia. They draw attention to an enhanced autonomic nervous system–mediated sigh–vasoconstrictor response in patients with sickle cell that could increase red cell retention in the microvasculature, promoting vasoocclusion.
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Affiliation(s)
- Suvimol Sangkatumvong
- Biomedical Engineering Department, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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Liu Q, Poon C, Zhang Y. Time–frequency analysis of variabilities of heart rate, systolic blood pressure and pulse transit time before and after exercise using the recursive autoregressive model. Biomed Signal Process Control 2011. [DOI: 10.1016/j.bspc.2011.03.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Cerutti S, Baselli G, Bianchi A, Caiani E, Contini D, Cubeddu R, Dercole F, Rienzo L, Liberati D, Mainardi L, Ravazzani P, Rinaldi S, Signorini M, Torricelli A. Biomedical signal and image processing. IEEE Pulse 2011; 2:41-54. [PMID: 21642032 DOI: 10.1109/mpul.2011.941522] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Generally, physiological modeling and biomedical signal processing constitute two important paradigms of biomedical engineering (BME): their fundamental concepts are taught starting from undergraduate studies and are more completely dealt with in the last years of graduate curricula, as well as in Ph.D. courses. Traditionally, these two cultural aspects were separated, with the first one more oriented to physiological issues and how to model them and the second one more dedicated to the development of processing tools or algorithms to enhance useful information from clinical data. A practical consequence was that those who did models did not do signal processing and vice versa. However, in recent years,the need for closer integration between signal processing and modeling of the relevant biological systems emerged very clearly [1], [2]. This is not only true for training purposes(i.e., to properly prepare the new professional members of BME) but also for the development of newly conceived research projects in which the integration between biomedical signal and image processing (BSIP) and modeling plays a crucial role. Just to give simple examples, topics such as brain–computer machine or interfaces,neuroengineering, nonlinear dynamical analysis of the cardiovascular (CV) system,integration of sensory-motor characteristics aimed at the building of advanced prostheses and rehabilitation tools, and wearable devices for vital sign monitoring and others do require an intelligent fusion of modeling and signal processing competences that are certainly peculiar of our discipline of BME.
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Affiliation(s)
- Sergio Cerutti
- Dipartimento di Bioingegneria, Politecnico di Milano, Italy
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Lagi A, Cencetti S, Cartei A. What Happens before Syncope? Study of the Time Frame Preceding Vasovagal Syncope. ISRN CARDIOLOGY 2011; 2011:659787. [PMID: 22347649 PMCID: PMC3262513 DOI: 10.5402/2011/659787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/18/2011] [Indexed: 11/30/2022]
Abstract
Objective. The events characterizing the very last part of the vasovagal crisis has not been determined. The aim of the study was to analyze the variations in respiratory pattern preceding the vaso-vagal syncope full-blown and the relationship between cardiovascular functions in order to assess the temporal sequence. Methods. Eleven consecutive patients were studied. Heart rate, arterial pressure, respiratory frequency, tidal volume, carbon dioxide, and oxygen saturation in time domain from supine and standing recordings were analyzed. Results. The respiratory activity is different in the time frame preceding syncope, both in VT and breathing rate, and that the increase of the lung ventilation does not influence the baroreflex control during the presyncopal period but may be cause of the baroreflex failure during the full-blown syncope.
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Affiliation(s)
- Alfonso Lagi
- Dipartimento di Medicina Interna, Ospedale Santa Maria Nuova, Piazza S. Maria Nuova, 50100 Firenze, Italy
| | - Simone Cencetti
- Dipartimento di Medicina Interna, Ospedale Santa Maria Nuova, Piazza S. Maria Nuova, 50100 Firenze, Italy
| | - Alessandro Cartei
- Dipartimento di Medicina Interna, Ospedale Santa Maria Nuova, Piazza S. Maria Nuova, 50100 Firenze, Italy
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Sangkatumvong S, Coates TD, Wood JC, Meiselman HJ, Kato R, Detterich JA, Bush A, Khoo MCK. Time-varying analysis of autonomic control in response to spontaneous sighs in sickle cell anemia. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2010:1626-9. [PMID: 21096136 DOI: 10.1109/iembs.2010.5626649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Sickle cell anemia (SCA) is a genetic disease which is characterized by painful episodes of vascular occlusions. In the present study, we investigated a potential contribution of the autonomic nervous system (ANS) in initiating such episodes. We observed prominent decreases in microvascular perfusion in response to spontaneous sighs, which may increase the likelihood of red blood cell polymerization followed by vascular occlusions in SCA patients. Time-varying spectral analysis of heart rate variability (HRV), based on recursive least squares estimation, was employed to study the modulation of the ANS in response to sighs. To improve robustness of the spectral estimation while retaining its ability to track rapid changes, we propose a time-varying parameter estimate variability reduction (TV-PEVR) technique. Because respiration patterns can vary considerably across subjects, we employed a time-varying autoregressive with exogenous input (TV-ARX) model to adjust for the effect of respiration patterns on the HRV indices. Results from 8 SCA subjects and 9 normal controls suggested that the cardiac ANS responses to sighs are not different between the two groups, after adjusting for the effect of post-sigh respiration. However, the peripheral sympathetic response in SCA appeared to be enhanced in this group relative to normals, and sighs may play a role in initiation of vaso-occlusive events in this group of patients.
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Affiliation(s)
- Suvimol Sangkatumvong
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089, USA.
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Kowalska MA, Kasprzak HT, Iskander DR, Danielewska M, Mas D. Ultrasonic in vivo measurement of ocular surface expansion. IEEE Trans Biomed Eng 2010; 58:674-80. [PMID: 21177153 DOI: 10.1109/tbme.2010.2100819] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Our aim was to ascertain whether the ultrasonic measurement of longitudinal corneal apex displacements carried out in a proper headrest is a credible method of ocular pulse (OP) detection. To distinguish between longitudinal movements of the eye globe treated as a rigid body and ocular surface expansion caused by the variations of the eye-globe volume, two ultrasound distance sensors were applied to noninvasively measure displacements of cornea and sclera. The same sensors were used to examine the influence of the anterio-posterior movements of a fixed head on the registration of corneal apex pulsation. In both experiments, ECG signals were synchronically recorded. Time, spectral, and coherence analyses obtained for four healthy subjects showed that the ocular surface expansion due to pulsatile ocular blood flow (POBF) is the main component of longitudinal corneal displacement. Ocular surface pulsation is always affected by the head movement. However, there exist some unique properties of signals, which help to distinguish between head and eye movements. A rigid headrest and a bite bar are required to stabilize the head during OP measurement. Ultrasonic technique enables noninvasive and accurate in vivo measurement of corneal pulsation, which could be of interest for indirectly estimating intraocular pressure propagation and POBF component.
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Egge C, Wyller VB. No differences in cardiovascular autonomic responses to mental stress in chronic fatigue syndrome adolescents as compared to healthy controls. Biopsychosoc Med 2010; 4:22. [PMID: 21156045 PMCID: PMC3012010 DOI: 10.1186/1751-0759-4-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 12/14/2010] [Indexed: 11/10/2022] Open
Abstract
Chronic fatigue syndrome (CFS) is a disabling disease with unknown etiology. There is accumulating evidence of altered cardiovascular autonomic responses to different somatic stressors, in particular orthostatic stress, whereas autonomic responses to mental stress remain to be investigated. In this study, we explored cardiovascular autonomic responses to a simple mental stress test in CFS patients and healthy controls.A consecutive sample of 13 patients with CFS, aged 12 to 18 years, and a volunteer sample of 53 healthy control subjects of equal age and gender distribution were included. Blood pressure, heart rate and acral skin blood flow were continuously recorded during an arithmetic exercise.At baseline, heart rate was significantly higher among CFS patients than controls (p = 0.02). During the arithmetic exercise, however, there were no significant differences in the responses between the two groups.In conclusion, CFS patients have unaltered autonomic responses to simple mental stress as compared to healthy control subjects.
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Affiliation(s)
- Caroline Egge
- Division of Pediatrics, Oslo University Hospital Rikshospitalet, Oslo, Norway.
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Zamir M, Goswami R, Liu L, Salmanpour A, Shoemaker JK. Myogenic activity in autoregulation during low frequency oscillations. Auton Neurosci 2010; 159:104-10. [PMID: 20829121 DOI: 10.1016/j.autneu.2010.07.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 07/07/2010] [Accepted: 07/29/2010] [Indexed: 11/28/2022]
Abstract
Lower body negative pressure (LBNP) was applied in eight human subjects to trigger low frequency oscillations in order to study the nature of functional coupling between the hemodynamic and autonomic nervous systems, with particular focus on how the myogenic response fits within this coupling. To this end muscle sympathetic nerve activity (MSNA), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), and total peripheral resistance (TPR) were measured at baseline and during LBNP and were then examined in both the time and frequency domains. At the height of low frequency oscillations (~0.1Hz) there was a strong coupling between all the five indices, marked by perfect alignment of their oscillatory frequencies. Results in the time domain show that a fall in MAP is followed by a fall in TPR at 1.58s SD 0.69), a rise in heart rate at 2.64s (SD 0.98), a rise in cardiac output at 3.72s (SD 0.60), a peak in MSNA at 5.71s (SD 1.27) and, finally, a rise in TPR at 7.13s (SD 1.02). A possible interpretation of the latter is that a drop in MAP first triggers a drop in TPR via a myogenic response before the expected rise in TPR via a rise in MSNA. In other words, following a drop in arterial pressure, myogenic response controls vessel diameter before this control is taken over by MSNA. These findings provide a possible resolution of a longstanding conceptual argument against attributing a significant role for the myogenic response in blood flow autoregulation.
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Affiliation(s)
- M Zamir
- Neurovascular Research Laboratory, School of Kinesiology, The University of Western Ontario, London, Ontario, Canada.
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Feature Extraction From Parametric Time–Frequency Representations for Heart Murmur Detection. Ann Biomed Eng 2010; 38:2716-32. [DOI: 10.1007/s10439-010-0077-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 03/17/2010] [Indexed: 10/19/2022]
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Kowalska MA, Kasprzak HT, Iskander DR. Comparison of high-speed videokeratoscopy and ultrasound distance sensing for measuring the longitudinal corneal apex movements. Ophthalmic Physiol Opt 2010; 29:227-34. [PMID: 19422553 DOI: 10.1111/j.1475-1313.2009.00648.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two different methods to measure binocular longitudinal corneal apex movements were synchronously applied. High-speed videokeratoscopy at a sampling frequency of 15 Hz and a custom-designed ultrasound distance sensor at 100 Hz were used for the left and the right eye, respectively. Four healthy subjects participated in the study. Simultaneously, cardiac electric cycle (ECG) was registered for each subject at 100 Hz. Each measurement took 20 s. Subjects were asked to suppress blinking during the measurements. A rigid headrest and a bite-bar were used to minimize undesirable head movements. Time, frequency and time-frequency representations of the acquired signals were obtained to establish their temporal and spectral contents. Coherence analysis was used to estimate the correlation between the measured signals. The results showed close correlation between both corneal apex movements and the cardiopulmonary system. Unraveling these relationships could lead to better understanding of interactions between ocular biomechanics and vision. The advantages and disadvantages of the two methods in the context of measuring longitudinal movements of the corneal apex are outlined.
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Affiliation(s)
- Malgorzata A Kowalska
- Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wrocław, Poland.
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19
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Selection of Dynamic Features Based on Time–Frequency Representations for Heart Murmur Detection from Phonocardiographic Signals. Ann Biomed Eng 2009; 38:118-37. [DOI: 10.1007/s10439-009-9838-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 11/06/2009] [Indexed: 10/20/2022]
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Sangkatumvong S, Khoo MCK, Coates TD. Abnormal cardiac autonomic control in sickle cell disease following transient hypoxia. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2008:1996-9. [PMID: 19163084 DOI: 10.1109/iembs.2008.4649581] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abnormalities in autonomic control in sickle cell anemia (SCA) patients have been reported by multiple researchers. However their potential causal association with sickle cell crisis remains unknown. We employed hypoxia, a known trigger to sickle cell crisis, to perturb the autonomic systems of the subjects. Cardiac autonomic control was non-invasively assessed by tracking the changes in heart rate variability (HRV) that occur following brief exposure to a hypoxia stimulus. Time varying spectral analysis of HRV was applied to estimate the cardiac autonomic response to the transient episode of hypoxia. The results demonstrate that cardiovascular autonomic response to hypoxia is substantially more sensitive in SCA than in normal controls. We also developed a model to compensate for the confounding effects of respiration on the HRV spectral indices by using the corresponding respiration signal to compensate for the respiratory correlated part of the HRV. This technique improved the resolution with which the effect of hypoxia on changes in HRV could be measured.
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Affiliation(s)
- Suvimol Sangkatumvong
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA 90089, USA.
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Blain G, Meste O, Blain A, Bermon S. Time-frequency analysis of heart rate variability reveals cardiolocomotor coupling during dynamic cycling exercise in humans. Am J Physiol Heart Circ Physiol 2009; 296:H1651-9. [DOI: 10.1152/ajpheart.00881.2008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To test the hypothesis that cycling exercise modulates heart rate variability (HRV), we applied a short-time Fourier transform on the electrocardiogram of subjects performing a maximal graded cycling test. A pedaling frequency component (PFC) in HRV was continuously observed over the time course of the exercise test and extracted from R-R interval series obtained from 15 healthy subjects with a heterogeneous physical fitness, exercising at three different pedaling frequency ( n = 5): 70, 80, and 90 rpm. From 30 to 50% of the maximal power output (Pmax), in the 90 rpm group, spectral aliasing caused PFC to overlap with the respiratory sinus arrhythmia (RSA) band, significantly overestimating the PFC amplitude ( APFC). In the meantime, APFC did not increase significantly from its minimal values in the 70 rpm (∼1.26 ms) and 80 rpm (∼1.20 ms) groups. Then, from 60 to 100% maximal power output (Pmax), workload increase caused a significant ∼2.8-, ∼3.3-, and ∼3.4-fold increase in APFC in the 70, 80, and 90 rpm groups, respectively, with no significant difference between groups. At peak exercise, APFC accounted for ∼43, ∼39, and ∼49% of the total HRV in the 70, 80, and 90 rpm groups, respectively. Our findings indicate that cycling continuously modulates the cardiac chronotropic response to exercise, inducing a new component in HRV, and that workload increase during intense exercise further accentuates this cardiolocomotor coupling. Moreover, because PFC and RSA overlapped at low workloads, methodological care should be taken in future studies aiming to quantify RSA as an index of parasympathetic activity.
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Keissar K, Davrath LR, Akselrod S. Coherence analysis between respiration and heart rate variability using continuous wavelet transform. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:1393-1406. [PMID: 19324715 DOI: 10.1098/rsta.2008.0273] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The continuous wavelet transform (CWT) is specifically efficient in the analysis of transient and non-stationary signals. As such, it has become a powerful candidate for time-frequency analysis of cardiovascular variability. CWT has already been established as a valid tool for the analysis of single cardiovascular signals, providing additional insights into the autonomous nervous system (ANS) activity and its control mechanism. Intercorrelation between cardiovascular signals elucidates the function of ANS central control and the peripheral reflex mechanisms. Wavelet transform coherence (WTC) can provide insight into the transient linear order of the regulatory mechanisms, via the computation of time-frequency maps of the time-variant coherence. This paper presents a framework for applying WTC for quantitative analysis of coherence in cardiovascular variability research. Computer simulations were performed to estimate the accuracy of the WTC estimates and a method for determining the coherence threshold for specific frequency band was developed and evaluated. Finally, we demonstrated, in two representative situations, the dynamic behaviour of respiration sinus arrhythmia through the analysis of the WTC between heart rate and respiration signals. This emphasizes that CWT and its application to WTC is a useful tool for dynamic analysis of cardiovascular variability.
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Affiliation(s)
- Kobi Keissar
- The Abramson Center for Medical Physics, Tel Aviv University, PO Box 39040, Tel Aviv 69978, Israel.
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Sangkatumvong S, Coates TD, Khoo MCK. Abnormal autonomic cardiac response to transient hypoxia in sickle cell anemia. Physiol Meas 2008; 29:655-68. [PMID: 18460753 DOI: 10.1088/0967-3334/29/5/010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to non-invasively assess cardiac autonomic control in subjects with sickle cell anemia (SCA) by tracking the changes in heart rate variability (HRV) that occur following brief exposure to a hypoxic stimulus. Five African-American SCA patients and seven healthy control subjects were recruited to participate in this study. Each subject was exposed to a controlled hypoxic stimulus consisting of five breaths of nitrogen. Time-varying spectral analysis of HRV was applied to estimate the cardiac autonomic response to the transient episode of hypoxia. The confounding effects of changes in respiration on the HRV spectral indices were reduced by using a computational model. A significant decrease in the parameters related to parasympathetic control was detected in the post-hypoxic responses of the SCA subjects relative to normal controls. The spectral index related to sympathetic activity, on the other hand, showed a tendency to increase the following hypoxic stimulation, but the change was not significant. This study suggests that there is some degree of cardiovascular autonomic dysfunction in SCA that is revealed by the response to transient hypoxia.
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Affiliation(s)
- S Sangkatumvong
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
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24
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Cnockaert L, Migeotte PF, Daubigny L, Prisk GK, Grenez F, Sa RC. A Method for the Analysis of Respiratory Sinus Arrhythmia Using Continuous Wavelet Transforms. IEEE Trans Biomed Eng 2008; 55:1640-2. [DOI: 10.1109/tbme.2008.918576] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Wyller VB, Saul JP, Amlie JP, Thaulow E. Sympathetic predominance of cardiovascular regulation during mild orthostatic stress in adolescents with chronic fatigue. Clin Physiol Funct Imaging 2007; 27:231-8. [PMID: 17564672 DOI: 10.1111/j.1475-097x.2007.00743.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Haemodynamic abnormalities have been documented in the chronic fatigue syndrome (CFS), indicating functional disturbances of the autonomic nervous system responsible for cardiovascular control. This study was designed to explore the pathophysiology in adolescent CFS-patients by analysing RR-interval (RRI) variability and diastolic blood pressure (DBP) variability during mild orthostatic stress, using an algorithm which accounts for non-stationary biosignals. A total of 27 adolescents with CFS and 33 healthy control subjects having equal age- and sex distribution underwent 15 min of 20 degrees head-up tilt (HUT). The spectral power densities of RRI and DBP were computed in the low-frequency (LF) band (0.04-0.15 Hz) and the high-frequency (HF) band (0.15-0.4 Hz) using an adaptive autoregressive algorithm to obtain a time-varying spectrum. RMSSD, a time domain index of RRI variability, was also computed. At rest, all indices of variability were similar in the two groups. During tilt, CFS patients had a larger increase in the LF/HF ratio (P<or=0.001) and normalized LF power of RRI (P<or=0.01), and a larger decrease in normalized HF power (P<or=0.01) of RRI than controls. CFS patients also had trends towards a larger decrease in absolute HF power of RRI and a larger increase in normalized LF power of DBP. These findings suggest that adolescents with CFS have sympathetic predominance of cardiovascular regulation during very mild orthostatic stress. Possible underlying mechanisms are moderate hypovolemia, abnormalities of reflex control or physical de-conditioning.
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Affiliation(s)
- Vegard B Wyller
- Department of Pediatrics, Rikshospitalet-Radiumhospitalet Medical Centre, Oslo, and Department of Pysiology, University of Oslo, Oslo, Norway.
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26
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Kasprzak HT, Iskander DR. Spectral characteristics of longitudinal corneal apex velocities and their relation to the cardiopulmonary system. Eye (Lond) 2006; 21:1212-9. [PMID: 16936640 DOI: 10.1038/sj.eye.6702578] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To study the naturally occurring kinetic characteristics of corneal surface. METHODS The right eyes of three subjects (young, early presbyope, and presbyope) were examined. Cardiac signal and longitudinal corneal apex movements were simultaneously measured with electrocardiography (ECG) and a high-speed videokeratoscope, respectively. Time, frequency, and combined time-frequency representations of the acquired signals were derived to establish their temporal and spectral contents. Coherence analysis was used to assess the correlation between the corneal apex velocities and the cardiopulmonary system. RESULTS In all measurements, longitudinal corneal apex velocity signals showed close correlation with the corresponding ECG signals. The signatures of the pulse frequency, which was inferred from the ECG spectra and their variations in time, were clearly visible in the spectral content of corneal apex velocities. For the young subject, the correlation was the strongest and all of the spectral content of the pulse signal including the harmonics was propagating to the corneal apex velocities. For the other two subjects, there was a clear propagation of the pulse signal itself but not of all pulse harmonics. CONCLUSIONS Longitudinal movements of the corneal apex are closely related to the cardiopulmonary system. The differences in propagation of pulse harmonics to the corneal apex velocities for different subjects suggest that the frequency characteristics of apex velocity could be related to pulsative variations in the intraocular pressure and biomechanical properties of the eye. These findings could potentially be used in noninvasive assessment of the hemodynamic status of the eye with high-speed videokeratoscopy.
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Affiliation(s)
- H T Kasprzak
- Faculty of Health, School of Optometry, Queensland University of Technology, Brisbane, Queensland, Australia
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27
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Goren Y, Davrath LR, Pinhas I, Toledo E, Akselrod S. Individual Time-Dependent Spectral Boundaries for Improved Accuracy in Time-Frequency Analysis of Heart Rate Variability. IEEE Trans Biomed Eng 2006; 53:35-42. [PMID: 16402601 DOI: 10.1109/tbme.2005.859784] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Heart rate variability (HRV) is a major noninvasive technique for evaluating the autonomic nervous system (ANS). Use of time-frequency approach to analyze HRV allows investigating the ANS behavior from the power integrals, as a function of time, in both steady-state and non steady-state. Power integrals are examined mainly in the low-frequency and the high-frequency bands. Traditionally, constant boundaries are chosen to determine the frequency bands of interest. However, these ranges are individual, and can be strongly affected by physiologic conditions (body position, breathing frequency). In order to determine the dynamic boundaries of the frequency bands more accurately, especially during autonomic challenges, we developed an algorithm for the detection of individual time-dependent spectral boundaries (ITSB). The ITSB was tested on recordings from a series of standard autonomic maneuvers with rest periods between them, and the response to stand was compared to the known physiological response. A major advantage of the ITSB is the ability to reliably define the mid-frequency range, which provides the potential to investigate the physiologic importance of this range.
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Affiliation(s)
- Yael Goren
- The Abramson Center for Medical Physics, Sackler Faculty of Exact Sciences, Tel-Aviv University, Israel
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28
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Martinmäki K, Rusko H, Saalasti S, Kettunen J. Ability of short-time Fourier transform method to detect transient changes in vagal effects on hearts: a pharmacological blocking study. Am J Physiol Heart Circ Physiol 2005; 290:H2582-9. [PMID: 16361363 DOI: 10.1152/ajpheart.00058.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Conventional spectral analyses of heart rate variability (HRV) have been limited to stationary signals and have not allowed the obtainment of information during transient autonomic cardiac responses. In the present study, we evaluated the ability of the short-time Fourier transform (STFT) method to detect transient changes in vagal effects on the heart. We derived high-frequency power (HFP, 0.20-0.40 Hz) as a function of time during active orthostatic task (AOT) from the sitting to standing posture before and after selective vagal (atropine sulfate 0.04 mg/kg) and sympathetic (metoprolol 0.20 mg/kg) blockades. The HFP minimum point during the first 30 s after standing up was calculated and compared with sitting and standing values. Reactivity scores describing the fast and slow HFP responses to AOT were calculated by subtracting the minimum and standing values from the sitting value, respectively. The present results, obtained without controlled respiration, showed that in the drug-free condition, HFP decreased immediately after standing up (P < 0.001) and then gradually increased toward the level characteristic for the standing posture (P < 0.001), remaining lower than in the sitting baseline posture (P < 0.001). The magnitudes of the fast and slow HFP responses to AOT were abolished by the vagal blockade (P < 0.001) and unaffected by the sympathetic blockade. These findings indicate that HFP derived by the STFT method provided a tool for monitoring the magnitude and time course of transient changes in vagal effects on the heart without the need to interfere with normal control by using blocking drugs.
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Affiliation(s)
- Kaisu Martinmäki
- KIHU-Research Institute for Olympic Sports, and Department of Biology of Physical Activity, University of Jyväskylä, FI-40014 Jyväskylä, Finland
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29
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Liddle E, Jackson G, Jackson S. An evaluation of a visual biofeedback intervention in dyslexic adults. DYSLEXIA (CHICHESTER, ENGLAND) 2005; 11:61-77. [PMID: 15747807 DOI: 10.1002/dys.287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A prototype of a biofeedback system designed to treat dyslexia by improving heart-rate variability was evaluated in a single blind study of dyslexic adults. Treatment consisted of four 15 minute exposures to a visual display synchronized with either the participant's own cardiac cycle (intervention condition), or of a synthesized cardiac cycle (placebo condition). Repeated measures were made of picture naming speed, single word reading speed and accuracy, copying speed, heart-rate variability and performance on a lateralized visual temporal order judgement task. Small but significant improvements were found in reading and naming speed in the treatment group relative to the placebo group. No significant improvements were found in unspeeded reading measures. Results from heart-rate measures indicated that treatment had effected a shift in the ratio between parameters reflecting the influence of the sympathetic and parasympathetic autonomic nervous systems (ANS), respectively, in favour of the parasympathetic. In the temporal order judgement task, participants who received treatment showed a reduced level of overall improvement relative to that seen in those who received placebo, coupled with evidence of a shift in visual attention from left to right hemifield in their pattern of performance. The results are interpreted as indicating that the treatment induces a shift in autonomic balance in favour of the parasympathetic ANS, and that this shift is also reflected in increased efficiency of left cerebral hemisphere circuits implicated in the perceptual-motor processes required for naming and reading fluency. Conversely, it is also reflected in lower spatial awareness of peripheral visual stimuli, particularly those presented to left hemifield.
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Affiliation(s)
- Elizabeth Liddle
- School of Psychology, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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Yoshiuchi K, Quigley KS, Ohashi K, Yamamoto Y, Natelson BH. Use of time-frequency analysis to investigate temporal patterns of cardiac autonomic response during head-up tilt in chronic fatigue syndrome. Auton Neurosci 2004; 113:55-62. [PMID: 15296795 DOI: 10.1016/j.autneu.2004.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2002] [Revised: 05/03/2004] [Accepted: 05/04/2004] [Indexed: 11/23/2022]
Abstract
Although a number of studies have reported alterations in cardiac autonomic nervous system function in chronic fatigue syndrome (CFS), the results are not consistent across studies. Reasons for these discrepancies include (1) the use of a heterogeneous patient sample that included those with orthostatic postural tachycardia (POTS), a condition with an autonomic changes, and (2) the use of frequency domain techniques which require a stationary signal and averaging data across relatively long epochs. To deal with these shortcomings, we used the smoothed pseudo-Wigner-Ville transform (SPWVT) to analyze heart rate variability (HRV) and blood pressure variability (BPV) during head-up tilt (HUT) by separating CFS patients into those with and without POTS. SPWVT has the advantage of providing instantaneous information about autonomic function under nonstable physiological conditions. We studied 18 CFS patients without POTS, eight CFS patients with POTS and 25 sedentary healthy controls during supine rest and during the first 10 min after HUT. While we found significant effects of postural change in both groups for all autonomic variables, there were significant group x time interactions between CFS without POTS and controls for only instant center frequency (ICF) within the low frequency region both from HRV (p=0.02) and from BPV (p=0.01). Although the physiological meaning of ICF still remains unknown, the data suggest that even CFS patients without POTS may have a subtle underlying disturbance in autonomic function.
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Affiliation(s)
- Kazuhiro Yoshiuchi
- Department of Neurosciences, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, East Orange, NJ 07018, USA
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Blain G, Meste O, Bermon S. Influences of breathing patterns on respiratory sinus arrhythmia in humans during exercise. Am J Physiol Heart Circ Physiol 2004; 288:H887-95. [PMID: 15388504 DOI: 10.1152/ajpheart.00767.2004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Persistence of respiratory sinus arrhythmia (RSA) has been described in humans during intense exercise and attributed to an increase in ventilation. However, the direct influence of ventilation on RSA has never been assessed. The dynamic evolution of RSA and its links to ventilation were investigated during exercise in 14 healthy men using an original modeling approach. An evolutive model was estimated from the detrended and high-pass-filtered heart period series. The instantaneous RSA frequency (FRSA, in Hz) and amplitude (ARSA, in ms) were then extracted from all recordings. A(RSA) was calculated with short-time Fourier transform. First, measurements of FRSA and ARSA were performed from data obtained during a graded and maximal exercise test. Influences of different ventilation regimens [changes in tidal volume (VT) and respiratory frequency (FR)] on ARSA were then tested during submaximal [70% peak O2 consumption (VO2peak)] rectangular exercise bouts. Under graded and maximal exercise conditions, ARSA decreased from the beginning of exercise to 61.9 +/- 3.8% VO2peak and then increased up to peak exercise. During the paced breathing protocol, normoventilation (69.4 +/- 8.8 l/min), hyperventilation (81.8 +/- 8.3 l/min), and hypoventilation (56.4 +/- 6.2 l/min) led to significantly (P < 0.01) different ARSA values (3.8 +/- 0.5, 4.6 +/- 0.8, and 2.9 +/- 0.5 ms, respectively). In addition, no statistical difference was found in ARSA when ventilation was kept constant, whatever the FR-VT combinations. Those results indicate that RSA persists for all exercise intensities and increases during the highest intensities. Its persistence and increase are strongly linked to both the frequency and degree of lung inflation, suggesting a mechanical influence of breathing on RSA.
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Affiliation(s)
- Grégory Blain
- Department of Ergonomics, University of Toulon-Var, La Gorde, France.
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Blasi A, Jo J, Valladares E, Morgan BJ, Skatrud JB, Khoo MCK. Cardiovascular variability after arousal from sleep: time-varying spectral analysis. J Appl Physiol (1985) 2003; 95:1394-404. [PMID: 12819215 DOI: 10.1152/japplphysiol.01095.2002] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We performed time-varying spectral analyses of heart rate variability (HRV) and blood pressure variability (BPV) recorded from 16 normal humans during acoustically induced arousals from sleep. Time-varying autoregressive modeling was employed to estimate the time courses of high-frequency HRV power, low-frequency HRV power, the ratio between low-frequency and high-frequency HRV power, and low-frequency power of systolic BPV. To delineate the influence of respiration on HRV, we also computed respiratory airflow high-frequency power, the modified ratio of low-frequency to high-frequency HRV power, and the average transfer gain between respiration and heart rate. During cortical arousal, muscle sympathetic nerve activity and heart rate increased and returned rapidly to baseline, but systolic blood pressure, the ratio between low-frequency and high-frequency HRV power, low-frequency HRV power, the modified ratio of low-frequency to high-frequency HRV power, and low-frequency power of systolic BPV displayed increases that remained above baseline up to 40 s after arousal. High-frequency HRV power and airflow high-frequency power showed concommitant decreases to levels below baseline, whereas the average transfer gain between respiration and heart rate remained unchanged. These findings suggest that 1) arousal-induced changes in parasympathetic activity are strongly coupled to respiratory pattern and 2) the sympathoexcitatory cardiovascular effects of arousal are relatively long lasting and may accumulate if repetitive arousals occur in close succession.
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Affiliation(s)
- Anna Blasi
- Biomedical Engineering Dept., OHE-500, Univ. Park, Los Angeles, CA 90089-1451, USA.
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33
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[To understand blood pressure and heart rate variability]. ANNALES FRANCAISES D'ANESTHESIE ET DE REANIMATION 2003; 22:425-52. [PMID: 12831970 DOI: 10.1016/s0750-7658(03)00134-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To review current data on the heart rate and blood pressure variability. DATA SOURCES Search through Medline databases of articles in french or english. DATA SELECTION Original articles and case reports were selected according to their quality and main advances. The articles were analysed in order to obtain current data about the methods of study and clinical application of blood pressure and heart rate variability. DATA SYNTHESIS Various regulatory systems in the cardiovascular system play crucial roles in controlling and assuring adequate perfusion of the peripheral tissues. Among them the baroreceptor reflex is the most important regulatory mechanism in the short-term control of the heart rate and blood pressure, and operates through the autonomic nervous system. The gain of the cardiac baroreflex further referred to, as baroreflex sensitivity is an interesting way to study this system. Unfortunately, with our current knowledge, it is not possible to predict the instantaneous output of the baroreceptor in response to instantaneous changes in input within a frequency range of physiological importance. The fast Fourier transform can describe variables as the sum of elementary oscillatory components and it has been established as practical clinical methods for detecting abnormalities in cardiovascular control. A time-frequency distribution provides an indication of how the spectral energy distribution varies with time and it is an interesting tool in non-stationary data. One of the major motivations behind spectral analysis is the hope that the combination of time-domain and frequency-domain analyses will provide dynamical informations about the relation between blood pressure and heart rate.
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Toledo E, Gurevitz O, Hod H, Eldar M, Akselrod S. Wavelet analysis of instantaneous heart rate: a study of autonomic control during thrombolysis. Am J Physiol Regul Integr Comp Physiol 2003; 284:R1079-91. [PMID: 12456384 DOI: 10.1152/ajpregu.00287.2002] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myocardial infarction (MI) is known to elicit activation of the autonomic nervous system. Reperfusion, induced by thrombolysis, is thus expected to bring about a shift in the balance between the sympathetic and vagal systems, according to the infarct location. In this study, we explored the correlation between reperfusion and the spectral components of heart rate (HR) variability (HRV), which are associated with autonomic cardiac control. We analyzed the HR of patients during thrombolysis: nine anterior wall MI (AW-MI) and eight inferoposterior wall MI (IW-MI). Reperfusion was determined from changes in ST levels and reported pain. Reocclusion was detected in four patients. HRV was analyzed using a modified continuous wavelet transform, which provided time-dependent versions of the typically used low-frequency (LF) and high-frequency (HF) peaks and of their ratio, LF/HF. Marked alterations in at least one of the HRV parameters was found in all 18 reperfusion events. Patterns of HRV, compatible with a shift toward relative sympathetic enhancement, were found in all of the nine reperfusion events in IW-MI patients and in three AW-MI patients. Patterns of HRV compatible with relative vagal enhancement were found in six AW-MI patients (P < 0.001). Significant changes in HRV parameters were also found after reocclusion. Time-dependent spectral analysis of HRV using the wavelet transform was found to be valuable for explaining the patterns of cardiac rate control during reperfusion. In addition, examination of the entire record revealed epochs of markedly diminished HRV in two patients, which we attribute to vagal saturation.
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Affiliation(s)
- Eran Toledo
- The Abramson Center for Medical Physics, Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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35
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Custaud MA, de Souza Neto EP, Abry P, Flandrin P, Millet C, Duvareille M, Fortrat JO, Gharib C. Orthostatic tolerance and spontaneous baroreflex sensitivity in men versus women after 7 days of head-down bed rest. Auton Neurosci 2002; 100:66-76. [PMID: 12422962 DOI: 10.1016/s1566-0702(02)00132-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Many factors are involved in the development of orthostatic intolerance after real or simulated weightlessness. The aim of our study was to compare the effects of 7-day head-down bed rest (HDBR) in eight women and eight men on the spontaneous baroreflex sensitivity (standard spectral method and new time-frequency algorithm) during lower body negative pressure (LBNP) tests. Results obtained before HDBR have shown in women, compared to men, higher heart rate, lower blood pressure, higher parasympathetic modulation at rest and greater decrease in baroreflex sensitivity with greater increase in sympathetic activity during LBNP. After HDBR, we observed in both men and women a dramatic decrease in orthostatic tolerance (7.0 min at R + 1 vs. 10.0 min, p<0.05, at BDC-1 in men; 5.4 vs. 9.0 min, p<0.05, in women) together with a decrease in plasma volume (-9.1 +/- 0.9% in men, -9.5 +/- 1.4% in women) and in spontaneous baroreflex sensitivity without gender effect. After HDBR, at the highest level of LBNP, diastolic blood pressure increased in men (+5.6 +/- 1.3 mm Hg) and decreased in women (-1.0 +/- 2.7 mm Hg) with a gender difference (p<0.05). This result suggests impaired vasoconstriction in women after HDBR. Neither endocrine response nor alterations to the cardiac baroreflex can explain gender differences in orthostatic tolerance after HDBR as reported by previous studies. Further studies need to be conducted in order to obtain a more precise analysis of gender difference in arteriolar vasoconstriction after HDBR. The time frequency method we developed to study changes in spontaneous baroreflex might be applied to the analysis of LBNP tests.
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