Dirk Cysarz - Academia.edu (original) (raw)

Papers by Dirk Cysarz

PLOS ONE, 2014

Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with ... more Six minute synchrogram showing a 25 s episode of synchronization starting at 221 s with three fetal beats occurring within two maternal beats at constant phase values (n:m = 3:2).</p

PLOS ONE, 2014

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015

Coarse graining of physiological time series such as the cardiac interbeat interval series by mea... more Coarse graining of physiological time series such as the cardiac interbeat interval series by means of a symbolic transformation retains information about dynamical properties of the underlying system and complements standard measures of heart rate variability. The transformations of the original time series to the coarse grained symbolic series usually lead to a non-uniform occurrence of the different symbols, i.e. some symbols appear more often than others influencing the results of the subsequent symbolic series analysis. Here, we defined a transformation procedure to assure that each symbol appears with equal probability using a short alphabet {0,1,2,3} and a long alphabet {0,1,2,3,4,5}. The procedure was applied to the cardiac interbeat interval series RRi of 17 healthy subjects obtained during graded head-up tilt testing. The symbolic dynamics is analyzed by means of the occurrence of short sequences (`words&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;) of length 3. The occurrence of words is grouped according to words without variations of the symbols (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%). Linear regression analysis with respect to tilt angle showed that for the short alphabet 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. For the long alphabet 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. These results were slightly better compared to the results from non-uniform symbolic transformations reflecting the deviation from the mean. In conclusion, the symbolic transformation assuring the appearance of symbols with equal probability is capable of reflecting changes of the cardiac autonomic nervous system during graded head-up tilt. Furthermore, the transformation is independent of the time series&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; distribution.

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015

Sensors

Intracranial pressure (ICP) burden or pressure time dose (PTD) is a valuable clinical indicator f... more Intracranial pressure (ICP) burden or pressure time dose (PTD) is a valuable clinical indicator for pending intracranial hypertension, mostly based on threshold exceedance. Pulse frequency and waveform morphology (WFM) of the ICP signal contribute to PTD. The temporal resolution of the ICP signal has a great influence on PTD calculation but has not been systematically studied yet. Hence, the temporal resolution of the ICP signal on PTD calculation is investigated. We retrospectively analysed continuous 48 h ICP recordings with high temporal resolution obtained from 94 patients at the intensive care unit who underwent neurosurgery due to an intracranial haemorrhage and received an intracranial pressure probe (43 females, median age: 72 years, range: 23 to 88 years). The cumulative area under the curve above the threshold of 20 mmHg was compared for different temporal resolutions of the ICP signal (beat-to-beat, 1 s, 300 s, 1800 s, 3600 s). Events with prolonged ICP elevation were com...

Physiological Measurement, Apr 18, 2017

Objective-Monitoring the fetal behavior does not only have implications for acute care but also f... more Objective-Monitoring the fetal behavior does not only have implications for acute care but also for identifying developmental disturbances that burden the entire later life. The concept, of 'fetal programming', also known as 'developmental origins of adult disease hypothesis', e.g. applies for cardiovascular, metabolic, hyperkinetic, cognitive disorders. Since the autonomic nervous system is involved in all of those systems, cardiac autonomic control may provide relevant functional diagnostic and prognostic information.

Acta neurochirurgica, 2021

Physiological Measurement, Oct 24, 2018

OBJECTIVE Symbolic transformations of the cardiac interbeat interval series yield a coarse-graine... more OBJECTIVE Symbolic transformations of the cardiac interbeat interval series yield a coarse-grained description of the dynamical information of the underlying system and complement standard measures of heart rate variability. The most commonly utilized coarse graining procedures are strongly influenced by the presence of a few extreme values wasting precious symbols to code very unlikely values. APPROACH Here, we used a transformation procedure that ensured the appearance of each symbol with equal probability using a short alphabet, A 4 = {0, 1, 2, 3}, and a long alphabet, A 6 = {0, 1, 2, 3, 4, 5}. The procedure was applied to the cardiac interbeat interval series of 17 healthy subjects, obtained during graded head-up tilt tests at tilt table inclinations of 0°, 15°, 30°, 45°, 60°, 75°, 90°. The dynamics of the symbolic series was assessed by the rate of symbolic pattern categories. Symbolic patterns of length three were grouped according to the variations of the symbols in each pattern: no variation (0V%), one variation (1V%), two like variations (2LV%) and two unlike variations (2UV%) of the symbols. MAIN RESULTS As for the alphabet A 4, the linear regression analysis on tilt angle showed that 0V% increased with increasing tilt angle whereas 1V%, 2LV% and 2UV% decreased. As for the alphabet A 6, the categories 0V%, and 1V% increased with increasing tilt angle whereas 2LV% and 2UV% decreased. SIGNIFICANCE The symbolic transformation ensuring a uniform distribution of the symbols is capable of reflecting changes in the cardiac autonomic nervous system during graded head-up tilt. This approach is more robust against outliers and data with skewed distributions compared to previously used symbolizations.

Physiological Measurement, Jun 1, 2019

Heart rate variability categories of fluctuation amplitude and complexity: diagnostic markers of ... more Heart rate variability categories of fluctuation amplitude and complexity: diagnostic markers of fetal development and its disturbances To cite this article: Dirk Hoyer et al 2019 Physiol. Meas. 40 064002 View the article online for updates and enhancements. You may also like Heart rate variability monitoring for emotion and disorders of emotion Jianping Zhu, Lizhen Ji and Chengyu Liu-Increase in random component of heart rate variability coinciding with developmental and degenerative stages of life Junichiro Hayano, Kei Ohashi, Yutaka Yoshida et al.-Correlation between RR, inter-systolic and inter-diastolic intervals and their differences for the analysis of spontaneous heart rate variability

The multiscale analysis of physiologic time series such as the RR interval time series has reveal... more The multiscale analysis of physiologic time series such as the RR interval time series has revealed that the entropy differs according to the scale. Furthermore, healthy subjects show different characteristics on the different time scales compared to patients. Instead of calculating entropies of the time series, the sequence of acceleration and deceleration of the instantaneous heart rate may also be investigated by means of binary symbolic dynamics. This kind of analysis revealed that the healthy heartbeat series also contains numerous regular binary sequences indicating runs of acceleration or deceleration. Here, we investigate whether this approach yields new information when applied to multiple time scales. We investigate the occurrence of binary patterns of length 8 on different time scales of heart rate series from healthy subjects and patients with congestive heart failure (CHF). Healthy subjects and CHF patients show different occurrences of binary patterns. These occurrences change especially on scales 1 to 5. Healthy subjects show more pronounced changes than CHF patients. At larger scales only gradual changes were observed. In conclusion, the application of binary symbolic dynamics on different scales yields new information, in particular on small scales.

$Research paper thumbnail of A proof-of-concept trial of HELIOX with different fractions of helium in a human study modeling upper airway obstruction$

European Journal of Applied Physiology, Mar 8, 2019

Background Helium in oxygen (HELIOX) can relieve airway obstruction and lower the work of breathi... more Background Helium in oxygen (HELIOX) can relieve airway obstruction and lower the work of breathing because it increases the threshold at which turbulent gas flow is induced. Less turbulent and more laminar flow lowers the work of breathing. According to guidelines, the fraction of Helium in HELIOX should be maximized (e.g. to 79%). Here, we investigate whether HELIOX with less than 60% of Helium is able to relieve the sensation of dyspnea in healthy volunteers. Methods 44 volunteers underwent resistive loading breathing different gases (medical air and HELIOX with a fraction of 25%, 50% or 75% helium in oxygen) in a double-blinded crossover design. Subjects rated their degree of dyspnea (primary outcome parameter) and the variability of noninvasively measured systolic blood pressure was assessed. Results Dyspnea was significantly reduced by HELIOX-containing mixtures with a fraction of helium of 25% or more. Similarly, blood pressure variability was reduced significantly even with helium 25% during respiratory loading with the higher load, whereas with the smaller load an effect could only be obtained with the highest helium fraction of 75%. Conclusion In this clinical trial, HELIOX with less than 60% of helium in oxygen decreased the sensation of dyspnea and blood pressure variability, a surrogate parameter for airway obstruction. Therefore, higher oxygen fractions might be applied without losing the helium-related benefits for the treatment of upper airway obstruction. Trial registration Registration with clinical trials (NCT00788788) and EMA (EudraCT number: 2006-005289-37).

Frontier Media SA eBooks, 2023

Frontiers in Integrative Neuroscience, Apr 4, 2023

Focus on Alternative and Complementary Therapies, Jun 14, 2010

Scientific Reports, Sep 22, 2020

Psychological stress may have harmful physiological effects and result in deteriorating health. A... more Psychological stress may have harmful physiological effects and result in deteriorating health. Acute psychological stress acts also on cardiac autonomic regulation and may lead to nonstationarities in the interbeat interval series. We address the requirement of stationary RR interval series to calculate frequency domain parameters of heart rate variability (HRV) and use binary symbolic dynamics derived from RR interval differences to overcome this obstacle. 24 healthy subjects (12 female, 20–35 years) completed the following procedure: waiting period, Trier Social Stress Test to induce acute psychological stress, recovery period. An electrocardiogram was recorded throughout the procedure and HRV parameters were calculated for nine 5-min periods. Nonstationarities in RR interval series were present in all periods. During acute stress the average RR interval and SDNN decreased compared to rest before and after the stress test. Neither low frequency oscillations (LF), high frequency oscillations (HF) nor LF/HF could unambiguously reflect changes during acute stress in comparison to rest. Pattern categories derived from binary symbolic dynamics clearly identified acute stress and accompanying alterations of cardiac autonomic regulation. Methods based on RR interval differences like binary symbolic dynamics should be preferred to overcome issues related to nonstationarities.

BMC Complementary and Alternative Medicine, 2017

Question "Kneipp Therapy" (KT) is a form of Complementary and Integrative Medicine (CIM) that inc... more Question "Kneipp Therapy" (KT) is a form of Complementary and Integrative Medicine (CIM) that includes a combination of hydrotherapy, herbal medicine, mind-body medicine, physical activities and healthy nutrition. Several Nursing homes (NH) in Germany started to integrate KT in the routine care of residents. The aim of this study was to investigate if caring with KT has effects on caregivers. Methods We conducted a prospective, exploratory, two-armed cohort study to compare NH with (KT group) and without KT (but with routine health preventive interventions; control group) over 12 months. Each NH with KT was matched to a control. Outcomes for caregivers included the SF-12 Health Survey, the Work Ability Index (WAI) and the Copenhagen Psychosocial Questionnaire (COPSOQ). Results Altogether 111 caregivers were included from 7 NH (KT group, n = 48) respectively 6 NH (control group, n = 63). 95% of caregivers were female (43.4 ± 11.3 years, BMI 26.6 ± 5.3). At baseline, caregivers of the KT group showed better values for the COP-SOQ scales "feedback" (p = 0.043), "job satisfaction" (p < 0.001) and "burnout" (p = 0.008). After 6 months the control group was better in the COPSOQ scales "predictability of work" (p = 0.045) and after 12 months for "sense of community" (p = 0.047) and the physical component scale of the SF-12 (p = 0.039) compared to the KT group. Conclusions The study showed only minor differences between the caregivers of both groups. Caregivers´workability, quality of life and psychosocial burden at work seems to be less influenced by a CIM-oriented working-place approach. Trial Registration DRKS-ID: DRKS00005049 P246 Efficacy of adjuvant topical Juniperus excelsa versus cryotherapy alone in the treatment of cutaneous leishmaniasis: a double-blind randomized controlled clinical trial

• Background: Patients' physiological stress reactions to surgery have been ameliorated by re nin... more • Background: Patients' physiological stress reactions to surgery have been ameliorated by re ning surgical techniques, and improving pain therapy. Moreover, another way to reduce stress could be the use of Rhythmical embrocation (RE), a type of bodily massage applied with soft strokes, which has been shown to reduce the subject's pulse rate and blood pressure. This trial will investigate whether RE is effective to reduce stress, and what effects it exerts on sleep quality, nausea and vomiting, pain, medication consumption, mood, mobility, and length of hospital. Furthermore, the occurrence of complications associated with RE will be established. • Methods: A randomized controlled, three-arm parallel group trial will include 60 patients with colorectal cancer scheduled for surgery, randomized into three different intervention groups: (1) RE performed by professionals, (2) RE performed by students; and (3) empathic conversation. The intervention will be performed twice daily over four consecutive postoperative days. Before and after the intervention days, heart rate variability (primary outcome) will be established overnight as a measure of stress. The patients will ll out questionnaires on pain, sleep, nausea/vomiting and well-being. Possible complications from RE will be recorded daily. Vital signs, medication and surgery data will be retrieved from the patient record. Nursing students will be interviewed about job satisfaction, empathy and their identi cation with RE. • Discussion: Massage has been shown to have stress relieving effects. However, it's effectiveness in clinical settings is rarely investigated. With the postoperative setting we investigate massage in a situation of high physiological stress. Reduction of stress perioperatively has shown to reduce complications and improve recovery. With heart rate variability we include a physiologic, objective parameter to supplement them against the questionnaire responses of patients. Massage might reduce stress in stressful situations in healthcare and contribute to a better outcome of these patients. Trial registration: The trial has been registered in the German Clinical Trials Register (DRKS) under the ID DRKS00023407 on 2 nd November 2020. The trial was approved by the ethics committee of the University

Copyright information:Taken from "Comparison of two different approaches ... more Copyright information:Taken from "Comparison of two different approaches in the detection of intermittent cardiorespiratory coordination during night sleep"BMC Physiology 2002;2():18-18.Published online 4 Dec 2002http://www.ncbi.nlm.nih.gov/pmc/articles/PMC140027/Copyright © 2002 Bettermann et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. The respiratory data remained unchanged. Despite this massive data manipulation the resulting gray-scale map of (lower diagram) does not change considerably compared to the original data (upper diagram). Only the 7:2 coordination after two o'clock is notably diminished. The course of Δ(black lines), which is per se identical for the original and the surrogate data, may explain this finding. During many periods of apparent coordination with = 3 and α = 0.03, bivariate signal variation is low. Thus intermittent phase coordination most likely results mainly from a central adjustment of heart rate and respiratory rate but not from real beat-to-beat phase synchronization.

PLOS ONE, 2014

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015

Sensors

Physiological Measurement, Apr 18, 2017

Acta neurochirurgica, 2021

Physiological Measurement, Oct 24, 2018

Physiological Measurement, Jun 1, 2019

$Research paper thumbnail of A proof-of-concept trial of HELIOX with different fractions of helium in a human study modeling upper airway obstruction$

European Journal of Applied Physiology, Mar 8, 2019

Frontier Media SA eBooks, 2023

Frontiers in Integrative Neuroscience, Apr 4, 2023

Focus on Alternative and Complementary Therapies, Jun 14, 2010

Scientific Reports, Sep 22, 2020

BMC Complementary and Alternative Medicine, 2017