Marcel Młyńczak

Marcel Młyńczak
Warsaw University of Technology · Institute of Metrology and Biomedical Engineering

PhD

About

68
Publications
22,051
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338
Citations
Introduction
Physiological measurements; Cardiorespiratory activity; Impedance pneumography; Sports medicine; Sleep medicine; Data science & Machine learning; Statistics; Signal and image processing; Causality
Additional affiliations
October 2014 - January 2018
Warsaw University of Technology
Position
  • PhD Student
Education
February 2013 - June 2014
Warsaw University of Technology
Field of study
  • Biomedical Engineering
October 2009 - January 2013
Warsaw University of Technology
Field of study
  • Biomedical Engineering

Publications

Publications (68)
Article
Manned spaceflight requires research in diverse areas, including neuropsychology and human physiology. For these subjects, the Lunares Analog Research Station was established in Pila, Poland. It allows testing of crew members under space-like conditions. One experiment, Lunar Expedition I, was performed on a group of 6 analogue astronauts over 14 d...
Article
Full-text available
Fitness level, fatigue and adaptation are important factors for determining the optimal training schedule and predicting future performance. We think that adding analysis of the mutual relationships between cardiac and respiratory activity enables better athlete profiling and feedback for improving training. Therefore, the main objectives were (1)...
Article
Full-text available
Training of elite athletes requires regular physiological and medical monitoring to plan the schedule, intensity and volume of training, and subsequent recovery. In sports medicine, ECG-based analyses are well-established. However, they rarely consider the correspondence of respiratory and cardiac activity. Given such mutual influence, we hypothesi...
Article
Full-text available
Obstetric anal sphincter injuries are the most common cause of fecal incontinence in women yet remain under-diagnosed. the aim of this study was to assess the suitability of impedance spectroscopy for diagnosing sphincter injuries arising during delivery. This was a prospective single-center study. 22 female patients were included: 10 with symptoms...
Article
Full-text available
Objective: Sleep-disordered breathing is both a clinical and a social problem. This implies the need for convenient solutions to simplify screening and diagnosis. The aim of the study was to investigate the sensitivity and specificity of a novel wireless system in detecting breathing and snoring episodes during sleep. Methods: A wireless acousti...
Preprint
Four different Granger causality-based methods - one linear and three nonlinear (Granger Causality, Kernel Granger Causality, large-scale Nonlinear Granger Causality, and Neural Network Granger Causality) were used for assessment and causal-based quantification of the respiratory sinus arrythmia (RSA) in the group of pediatric cardiac patients, bas...
Conference Paper
Four different Granger causality-based methods - one linear and three nonlinear (Granger Causality, Kernel Granger Causality, large-scale Nonlinear Granger Causality, and Neural Network Granger Causality) were used for assessment and causal-based quantification of the respiratory sinus arrythmia (RSA) in the group of pediatric cardiac patients, bas...
Article
Full-text available
It is well documented that body position significantly affects breathing indices during sleep in patients with obstructive sleep apnea. They usually worsen while changing from a non-supine to a supine position. Therefore, body position should be an accurately measured and credible parameter in all types of sleep studies. The aim of this study was t...
Article
Full-text available
Background and Objective Causality defined by Granger in 1969 is a widely used concept, particularly in neuroscience and economics. As there is an increasing interest in nonlinear causality research, a Python package with a neural-network-based causality analysis approach was created. It allows performing causality tests using neural networks based...
Article
Full-text available
Background and purpose: Most studies on heart rate variability (HRV) in professional athletes concerned linear, time- and frequency-domain indices and there is lack of studies on nonlinear parameters in this group. The study aimed to determine the inter-day reliability, and group-related and individual changes of short-term symbolic dynamics (SymDy...
Article
Full-text available
Purpose Polysomnography (PSG) is considered the best objective study to diagnose and quantify sleep disorders. However, PSG involves multiple electrodes and is usually performed in a sleep laboratory that in itself may change the physiology of sleep. One of the parameters that can change during PSG is the sleep position, leading to more supine slee...
Article
Full-text available
The current diagnostic procedures for assessing physiological response to exercise comprise blood lactates measurements, ergospirometry, and electrocardiography. The first is not continuous, the second requires specialized equipment distorting natural breathing, and the last is indirect. Therefore, we decided to perform the feasibility study with i...
Article
The Apnea-Hypopnea Index (AHI) is one of the most-used parameters from sleep studies that allows assessing both the severity of obstructive sleep apnea and the reliability of new devices and methods. However, assessment is commonly based on comparison with a reference only via a correlation coefficient measure. In this paper, we discuss the limitat...
Article
Full-text available
Objectives The aim of the study was to identify predictors determining the course of COVID-19 and antibody response in elite athletes. Design Observational study. Methods Routine medical screening with physical examination, resting ECG, and laboratory tests including antibody response was performed 12-68 days after the diagnosis of COVID-19 in 11...
Chapter
Impedance pneumography is a method of non-invasive, comfortable and continuous respiratory activity measurement, that allows recording quantitative parameters of respiratory rate, tidal volume, minute ventilation or airflows. The presented chapter presents the comparison to spirometry and pneumotachometry; instrumentation, electrodes and their conf...
Article
Full-text available
Otitis media, a common disease marked by the presence of fluid within the middle ear space, imparts a significant global health and economic burden. Identifying an effusion through the tympanic membrane is critical to diagnostic success but remains challenging due to the inherent limitations of visible light otoscopy and user interpretation. Here w...
Article
Full-text available
Anal sphincter injuries occurring during natural deliveries are often a reason for severe complications, including fecal incontinence. Currently, approximately 80% of these injuries remain unrecognized. Therefore, it is crucial to focus on finding a way to diagnose such injuries as early as possible to apply the tailored treatment. This study aimed...
Article
Full-text available
This study aims to evaluate the accuracy of a wireless tracheal audio sensor including the sleep body position measurement, as a possible tool to screen for obstructive sleep apnea (OSA) and also to distinguish among ''positional'' and ''non-positional'' sleep apnea patients. 30 adult subjects were asked to sleep naturally for a single night in the...
Article
Full-text available
Background To assess left ventricular hypertrophy, actual left ventricular mass (LVM) normalized for body size has to be compared to the LVM normative data. However, only some published normative echocardiographic data have been produced separately for girls and boys; numerous normative data for the pediatric population are not sex-specific. Thus,...
Conference Paper
In addition to the global parameter- and time-series-based approaches, physiological analyses should constitute a local temporal one, particularly when analyzing data within protocol segments. Hence, we introduce the R package implementing the estimation of temporal orders with a causal vector (CV). It may use linear modeling or time series distanc...
Article
Full-text available
Vitamin D is a nutrient whose active form affects tissues as a hormone and possibly enhances performance. One plausible mechanism is by increasing testosterone concentration, which is established as an important factor for athletic performance. Therefore the aim of the study was to examine the relationship between plasma concentration of 25(OH)D an...
Article
Full-text available
Background: Athletes and coaches believe in the ergogenic effect of vitamin B12 (which results from enhanced erythropoiesis) and they often insist on its unjustified supplementation. Therefore, our study aimed to assess the vitamin B12 status in Polish elite athletes and its influence on red blood cell parameters. Methods: In total, 1131 blood s...
Article
Objective: The aim of the study was to evaluate the safety and tolerance of influenza vaccines for the northern and southern hemispheres in Polish elite athletes participating in the Rio 2016 Olympics. Design: Prospective, observational, cohort study. Setting: Institutional level. Participants: Ninety-seven athletes vaccinated only with the...
Article
Full-text available
Research on reliability of heart rate variability (HRV) parameters in athletes has received increasing attention. The aims of this study were to examine the inter-day reliability of short-term (5 min) and ultra-short-term (1 min) heart rate (HR), respiratory rate (RespRate) and HRV parameters, agreement between short-term and ultra-short-term param...
Article
Full-text available
Background Normalization for body size is required for reliable left ventricular mass (LVM) evaluation, especially in children due to the large variability of body size. In clinical practice, the allometrically adjusted ratio of LVM to height raised to the power of 2.7 is often used. However, studies presenting normative LVM data for children recom...
Preprint
The Apnea-Hypopnea Index (AHI) is one of the most-used parameters from the sleep study that allows assessing both the severity of obstructive sleep apnea and the reliability of new devices and methods. However, in many cases, it is compared with a reference only via a correlation coefficient, or this value is at least the most emphasized. In this p...
Article
Full-text available
Background Left ventricular mass normalization for body size is recommended, but a question remains: what is the best body size variable for this normalization—body surface area, height or lean body mass computed based on a predictive equation? Since body surface area and computed lean body mass are derivatives of body mass, normalizing for them ma...
Chapter
Full-text available
Impairment of the pelvic floor muscles and fecal incontinence affect 5–10% of the adult populations of European states. The most common cause is perinatal obstetrical anal sphincter injury (OASI) resulting from vaginal delivery. There is no method for screening in the period immediately after delivery. Diagnosis is limited to physical examination....
Data
The Matlab script used for calculating G-causalities.
Data
The R script consisting of the TiMINo analysis, exploratory data visualization and recursive feature elimination.
Data
The data comprising all calculated G-causalities (columns) for all considered participants (rows); NA - not assigned (when statistically insignificant); stored as an RData file (ready to load into R for analysis).
Article
Full-text available
It has been demonstrated that regular sport activity in children leads to physiological changes in the heart including increased left ventricular (LV) myocardial thickness and mass (LVM). The aim of the study was to establish the first specific normal values of LVM for child and adolescent athletes. Parasternal long-axis, 2D-guided echocardiographi...
Data
The R script comprising all algorithms mentioned in the text, from loading of the above data to delivery of final outcomes.
Data
The data file with cardiac and respiratory parameters calculated from all participants for the two body positions.
Article
Full-text available
Background Application of normative data for echocardiographic measurements to children practicing sports may lead to false positive findings. The aim of the study was to define the normative data of basic echocardiographic measurements for this group and to compare them to the previously published normative data for the pediatric population. Met...
Data
Linear dimensions comparison study_database. (CSV)
Data
Coefficients for regression equations relating echocardiographic measurements and body surface area, mean squared error, and adjusted coefficient of determination which appeared optimal in terms of utilized input variables. (DOCX)
Conference Paper
Full-text available
The aim was to determine causal paths affecting basic cardiac and respiratory parameters in elite athletes using Pneumonitor 2. Criteria based on generalized correlations and kernel regressions were used to establish appropriate directions and strengths of the relationships. Average activity parameters affect the diversity indicator. No strong conn...
Conference Paper
Full-text available
Typical disposable Ag/AgCl electrodes have potential drawbacks from a long-term measurement perspective. Particularly , they can cause an allergic reaction of the skin and can detach in case of sweating during physical activity or sleep. As they are disposable, the electrodes cannot be removed for cleaning. They must be connected to a device with s...
Conference Paper
Full-text available
Growing number of applications in which respiratory activity could be measured during natural functioning of patients amplifies the need for replacement of spirometric or pneumotachometric testing with other, indirect methods. One of them, impedance pneumography, thanks to the use of electrodes mounted on the chest, can produce signals distorted by...
Conference Paper
Full-text available
In Ambulatory Impedance Cardiography (AICG), a large number of motion artifacts might occur in recordings collected during exercises. The adequate identification of the artifacts is the most important task for automatic analysis of the AICG signals. The aim of this study was to manually assess the efficiency of the classification algorithm describe...
Conference Paper
Full-text available
Asthma is a chronic disease characterized by recurrent attacks of breathlessness and wheezing. During an asthma attack, a bronchospasm occurs. In order to overcome increased resistance of airways forced breathing is necessary. It affects the intrapleural pressure, blood volume within the thoracic cavity and therefore it may affect also impedance pn...
Conference Paper
Full-text available
Impedance pneumography (IP) is mainly used as a noninvasive method to measure respiratory rate, tidal volume or minute ventilation. It could also register flow-related signals, after differentiation, from spirometry-based forced vital capacity maneuvers or ambulatory-based signals reflecting flow values during natural activity. The aim of this pape...
Conference Paper
Full-text available
Impedance pneumography (IP) measures changes of thoracic electrical impedance connected with change of the air volume in the lungs. The electrode configuration used in IP applications causes that electrical heart activity is visible in the IP signals. The aim of this paper is to assess the opportunity to decompose both respiratory and cardiac compo...
Conference Paper
Full-text available
Holter-type devices with sets of sensors, enabling long-term measurement of quantitative respiratory parameters , were designed and constructed. Pneumonitor 2 was intended for physiologic and athletic applications, and Pneumonitor 3 for sleep studies. Both allow simultaneous, comfortable, ambulatory monitoring of cardiorespi-ratory activity, such a...
Poster
Full-text available
Habitat Lunares is a simulated space base and chronobiological laboratory to perform advanced studies on humans in controlled conditions [1]. With common effort of Medical University in Poznań, Lunares became the first in Poland laboratory of extreme medicine. People living in this base are constantly monitored by telemedical devices. Additionally,...
Article
Full-text available
Vitamin D does not only influence the musculoskeletal health and mineral homeostasis but it also affects cardiovascular, endocrine, nervous, immune and mental functions, thus it is of considerable importance for both physically active people and elite athletes. However, vitamin D deficiency is common worldwide and results from inadequate endogenous...
Data
The serum 25(OH)D concentration of all examined athletes. Consecutive values of all the performed measurements throughout the whole study period. (PDF)
Article
Full-text available
About 5% of European population (similarly for the globe) of any age suffer from obstructive sleep apnea. Other breathing disturbances during sleep (primarily habitual snoring) occur in more than 25% of the population. Polysomnography is a gold standard in diagnosing sleep disordered breathing, however it is expensive and impossible to be used as a...
Article
Full-text available
Oral breathing is a real problem in pediatric population, which could cause respiratory or orthodontic disorders. Early diagnosis allows proper intervention (in most cases ENT or orthodontic treatment), however it is usually studied through surveys with parents, which are not sufficiently reliable. The aim of the work was to assess the accuracy of...
Conference Paper
Full-text available
Heart activity, or at least heart rate variability, is associated with body position. Our previous studies have confirmed that impedance pneumography may be used to record respiratory function, but the calibration coefficients for this method depend on position. Data were collected from 24 students (12 male, 12 female), who alternated positions bet...
Conference Paper
Full-text available
The aim of this work was to assess the impact of breathing mechanics, body posture and subject's physique on heart rate variability (HRV). 13 healthy students performed series of breathing with different rates and depths, while supine, sitting and standing. Impedance pneumography (IP) and electrocardiography signals were registered. Repeated ANOVA...
Chapter
Full-text available
Impedance pneumography could be used for measuring respiratory parameters quantitatively in ambulatory conditions. It was noted that body posture affects the calibration coefficient connecting the measured impedance values and their first derivatives with volume and flow reference signals. Standard techniques for automatic detection of body posture...
Article
Full-text available
The aim was to assess accuracy of tidal volumes (TV) calculated by impedance pneumography (IP), reproducibility of calibration coefficients (CC) between IP and pneumotachometry (PNT), and their relationship with body posture, breathing rate and depth. Fourteen students performed three sessions of 18 series: normal and deep breathing at 6, 10, 15 br...
Conference Paper
Full-text available
The haemodynamics of the arterial system can be described by the three-elements Windkessel model. As it is a lumped model, it does not account for pulse wave propagation phenomena: pulse wave velocity, reflection, and pulse pressure profile changes during propagation. The Modelflow© method uses this model to calculate stroke volume and total periph...
Conference Paper
Full-text available
Respiration is the main reason of the chest movements. However, there are also non-respiratory ones, resulting from e.g. snoring, wheezing, stridor, throat clearing or coughing. They may exist sporadically, however should be examined in case when their incidences increase. Detecting non-respiratory movements is very important, because many of them...
Conference Paper
Full-text available
Cough monitoring is an important element of the diagnostics of respiratory diseases. The European Respiratory Society recommends objective assessment of cough episodes and the search for methods of automatic analysis to make obtaining the quantitative parameters possible. The cough " events " could be classified by a microphone and a sensor that me...
Conference Paper
Full-text available
We designed a small, battery-powered impedance pneumograph intended for holter monitoring of respiratory activity. Volume-related signal from impedance pneumo-graphy (IP) and airflow signal from reference method, pneumotachometry (PNT), were registered. First derivate of IP with PNT and IP with integral of PNT signals were compared in order to calc...
Conference Paper
Full-text available
Flow-volume loops are used to calculate dynamic respiratory parameters. We examined whether our newly developed impedance pneumograph is able to measure properly respiratory parameters during Forced Vital Capacity (FVC) maneuver. Impedance measurements were performed using an electrode configuration known for providing good linearity between impeda...
Conference Paper
Full-text available
Aims: The estimation of respiratory flow and volume parameters is difficult to perform and uncomfortable for the patient during long-term monitoring outside the clinical environment. It is also hard to perform during sleep due to the usage of a facemask. The impedance pneumography (IP) device allows monitoring of breathing activity, estimates the r...