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Methods of Information in Medicine

Etsuko Shimizu, Toru Nakamura, Jinhyuk Kim, Kazuhiro Yoshiuchi, Yoshiharu Yamamoto
BACKGROUND: The mutual dependencies between mother and infant circadian rhythms are important for examining disturbances of maternal circadian rhythms, which are considered substantial risk factors for the development of maternal depression during childrearing periods. OBJECTIVES: We characterized the mutual dependencies of maternal-infant circadian rhythms by an index of synchronization properties and then tested the hypothesis that such an index, specifically the instantaneous phase differences between their rhythms, is associated with maternal mental health...
May 2018: Methods of Information in Medicine
Roberto Leonarduzzi, Patrice Abry, Herwig Wendt, Ken Kiyono, Yoshiharu Yamamoto, Eiichi Watanabe, Junichiro Hayano
BACKGROUND: Atrial fibrillation (AF) is an identified risk factor for ischemic strokes (IS). AF causes a loss in atrial contractile function that favors the formation of thrombi, and thus increases the risk of stroke. Also, AF produces highly irregular and complex temporal dynamics in ventricular response RR intervals. Thus, it is hypothesized that the analysis of RR dynamics could provide predictors for IS. However, these complex and nonlinear dynamics call for the use of advanced multiscale nonlinear signal processing tools...
May 2018: Methods of Information in Medicine
Gaetano Valenza, Luca Iozzia, Luca Cerina, Luca Mainardi, Riccardo Barbieri
BACKGROUND: There is a fast growing interest in the use of non-contact devices for health and performance assessment in humans. In particular, the use of non-contact videophotoplethysmography (vPPG) has been recently demonstrated as a feasible way to extract cardiovascular information. Nevertheless, proper validation of vPPG-derived heartbeat dynamics is still missing. OBJECTIVE: We aim to an in-depth validation of time-varying, linear and nonlinear/complex dynamics of the pulse rate variability extracted from vPPG...
May 2018: Methods of Information in Medicine
Steffen Schulz, Mathias Bolz, Karl-Jürgen Bär, Andreas Voss
BACKGROUND: The central control of the autonomic nervous system (ANS) and the complex interplay of its components can be described by a functional integrated mode - the central autonomic network (CAN). CAN represents the integrated functioning and interaction between the central nervous system (CNS) and ANS (parasympathetic and sympathetic activity). OBJECTIVE: This study investigates the central cardiovascular network (CCVN) as a part of the CAN, during which heart rate (HR), systolic blood pressure (SYS) and frontal EEG activity in 21 healthy subjects (CON) will be analysed...
May 2018: Methods of Information in Medicine
Ikuhiro Yamaguchi, Akifumi Kishi, Fumiharu Togo, Toru Nakamura, Yoshiharu Yamamoto
OBJECTIVES: This study aimed to describe a robust method with high time resolution for estimating the cortico-thalamo-cortical (CTC) loop strength and the delay when using a scalp electroencephalography (EEG) and to illustrate its applicability for analyzing the wake-sleep transition. METHODS: The basic framework for the proposed method is the parallel use of a physiological model and a parametric phenomenological model: a neural field theory (NFT) of the corticothalamic system and an autoregressive (AR) model...
May 2018: Methods of Information in Medicine
Kazuo Yana, Yoshiharu Yamamoto, Taishin Nomura
No abstract text is available yet for this article.
May 2018: Methods of Information in Medicine
Felicitas Vogelgesang, Peter Schlattmann, Marc Dewey
BACKGROUND: Meta-analyses require a thoroughly planned procedure to obtain unbiased overall estimates. From a statistical point of view not only model selection but also model implementation in the software affects the results. OBJECTIVES: The present simulation study investigates the accuracy of different implementations of general and generalized bivariate mixed models in SAS (using proc mixed, proc glimmix and proc nlmixed), Stata (using gllamm, xtmelogit and midas) and R (using reitsma from package mada and glmer from package lme4)...
May 2018: Methods of Information in Medicine
Saman Abdullah, Thomas Bouchard, Amna Klich, Rene Leiva, Cecilia Pyper, Christophe Genolini, Fabien Subtil, Jean Iwaz, René Ecochard
BACKGROUND: Even in normally cycling women, hormone level shapes may widely vary between cycles and between women. Over decades, finding ways to characterize and compare cycle hormone waves was difficult and most solutions, in particular polynomials or splines, do not correspond to physiologically meaningful parameters. OBJECTIVE: We present an original concept to characterize most hormone waves with only two parameters. METHODS: The modelling attempt considered pregnanediol-3-alpha-glucuronide (PDG) and luteinising hormone (LH) levels in 266 cycles (with ultrasound-identified ovulation day) in 99 normally fertile women aged 18 to 45...
May 2018: Methods of Information in Medicine
Geraldine Rauch, Werner Brannath, Matthias Brückner, Meinhard Kieser
BACKGROUND: In many clinical trial applications, the endpoint of interest corresponds to a time-to-event endpoint. In this case, group differences are usually expressed by the hazard ratio. Group differences are commonly assessed by the logrank test, which is optimal under the proportional hazard assumption. However, there are many situations in which this assumption is violated. Especially in applications were a full population and several subgroups or a composite time-to-first-event endpoint and several components are considered, the proportional hazard assumption usually does not simultaneously hold true for all test problems under investigation...
May 2018: Methods of Information in Medicine
Yong Chen, Marko Zivkovic, Tongtong Wang, Su Su, Jianyi Lee, Edward A Bortnichak
BACKGROUND: Clinical coding systems have been developed to translate real-world healthcare information such as prescriptions, diagnoses and procedures into standardized codes appropriate for use in large healthcare datasets. Due to the lack of information on coding system characteristics and insufficient uniformity in coding practices, there is a growing need for better understanding of coding systems and their use in pharmacoepidemiology and observational real world data research. OBJECTIVES: To determine: 1) the number of available coding systems and their characteristics, 2) which pharmacoepidemiology databases are they adopted in, 3) what outcomes and exposures can be identified from each coding system, and 4) how robust they are with respect to consistency and validity in pharmacoepidemiology and observational database studies...
February 2018: Methods of Information in Medicine
Eric J Daza
Many of an individual's historically recorded personal measurements vary over time, thereby forming a time series (e.g., wearable-device data, self-tracked fitness or nutrition measurements, regularly monitored clinical events or chronic conditions). Statistical analyses of such n-of-1 (i.e., single-subject) observational studies (N1OSs) can be used to discover possible cause-effect relationships to then self-test in an n-of-1 randomized trial (N1RT). However, a principled way of determining how and when to interpret an N1OS association as a causal effect (e...
February 2018: Methods of Information in Medicine
George Mnatzaganian, Melanie Bish, Jason Fletcher, Cameron Knott, John Stephenson
OBJECTIVE: This study aimed to determine how the abilities of the Charlson Index and Elixhauser comorbidities compared with the chronic health components of the Acute Physiology and Chronic Health Evaluation (APACHE II) to predict in-hospital 30 day mortality among adult critically ill patients treated inside and outside of Intensive Care Unit (ICU). METHODS: A total of 701 critically ill patients, identified in a prevalence study design on four randomly selected days in five acute care hospitals, were followed up from the date of becoming critically ill for 30 days or until death, whichever occurred first...
February 2018: Methods of Information in Medicine
Christian Salem, Danielle Azar, Sima Tokajian
Melanoma skin cancer is the most aggressive type of skin cancer. It is most commonly caused by excessive exposure to Ultraviolet radiation which triggers uncontrollable proliferation of melanocytes. Early detection makes melanoma relatively easily curable. Diagnosis is usually done using traditional methods such as dermoscopy which consists of a manual examination performed by the physician. However, these methods are not always well founded because they depend heavily on the physician's experience. Hence, there is a great need for a new automated approach in order to make diagnosis more reliable...
February 2018: Methods of Information in Medicine
Nishant Kumar, Laura J Tafe, John H Higgins, Jason D Peterson, Francise Blumental de Abreu, Sophie J Deharvengt, Gregory J Tsongalis, Christopher I Amos, Saeed Hassanpour
OBJECTIVE: We aim to build an informatics methodology capable of identifying statistically significant associations between the clinical findings of non-small cell lung cancer (NSCLC) recorded in patient pathology reports and the various clinically actionable genetic mutations identified from next-generation sequencing (NGS) of patient tumor samples. METHODS: We built an information extraction and analysis pipeline to identify the associations between clinical findings in the pathology reports of patients and corresponding genetic mutations...
February 2018: Methods of Information in Medicine
Idoia Berges, Jesus Bermúdez, Arantza Illarramendi
BACKGROUND: Single-Subject Design is used in several areas such as education and biomedicine. However, no suited formal vocabulary exists for annotating the detailed configuration and the results of this type of research studies with the appropriate granularity for looking for information about them. Therefore, the search for those study designs relies heavily on a syntactical search on the abstract, keywords or full text of the publications about the study, which entails some limitations...
February 2018: Methods of Information in Medicine
Huanying Gu, Zhe He, Duo Wei, Gai Elhanan, Yan Chen
BACKGROUND: The UMLS assigns semantic types to all its integrated concepts. The semantic types are widely used in various natural language processing tasks in the biomedical domain, such as named entity recognition, semantic disambiguation, and semantic annotation. Due to the size of the UMLS, erroneous semantic type assignments are hard to detect. It is imperative to devise automated techniques to identify errors and inconsistencies in semantic type assignments. OBJECTIVES: Designing a methodology to perform programmatic checks to detect semantic type assignment errors for UMLS concepts with one or more SNOMED CT terms and evaluating concepts in a selected set of SNOMED CT hierarchies to verify our hypothesis that UMLS semantic type assignment errors may exist in concepts residing in semantically inconsistent groups...
February 2018: Methods of Information in Medicine
Jesús Escrivá Muñoz, Pedro Gambús, Erik W Jensen, Montserrat Vallverdú
OBJECTIVE: This works investigates the time-frequency content of impedance cardiography signals during a propofol-remifentanil anesthesia. MATERIALS AND METHODS: In the last years, impedance cardiography (ICG) is a technique which has gained much attention. However, ICG signals need further investigation. Time-Frequency Distributions (TFDs) with 5 different kernels are used in order to analyze impedance cardiography signals (ICG) before the start of the anesthesia and after the loss of consciousness...
January 2018: Methods of Information in Medicine
Xingyu Zhang, Joyce Kim, Rachel E Patzer, Stephen R Pitts, Aaron Patzer, Justin D Schrager
OBJECTIVE: To describe and compare logistic regression and neural network modeling strategies to predict hospital admission or transfer following initial presentation to Emergency Department (ED) triage with and without the addition of natural language processing elements. METHODS: Using data from the National Hospital Ambulatory Medical Care Survey (NHAMCS), a cross-sectional probability sample of United States EDs from 2012 and 2013 survey years, we developed several predictive models with the outcome being admission to the hospital or transfer vs...
October 26, 2017: Methods of Information in Medicine
Marcos A Mouriño-García, Roberto Pérez-Rodríguez, Luis E Anido-Rifón
OBJECTIVES: The ability to efficiently review the existing literature is essential for the rapid progress of research. This paper describes a classifier of text documents, represented as vectors in spaces of Wikipedia concepts, and analyses its suitability for classification of Spanish biomedical documents when only English documents are available for training. We propose the cross-language concept matching (CLCM) technique, which relies on Wikipedia interlanguage links to convert concept vectors from the Spanish to the English space...
October 26, 2017: Methods of Information in Medicine
Darragh F Whelan, Martin A O'Reilly, Tomás E Ward, Eamonn Delahunt, Brian Caulfield
BACKGROUND: The barbell squat is a popularly used lower limb rehabilitation exercise. It is also an integral exercise in injury risk screening protocols. To date athlete/patient technique has been assessed using expensive laboratory equipment or subjective clinical judgement; both of which are not without shortcomings. Inertial measurement units (IMUs) may offer a low cost solution for the objective evaluation of athlete/patient technique. However, it is not yet known if global classification techniques are effective in identifying naturally occurring, minor deviations in barbell squat technique...
October 26, 2017: Methods of Information in Medicine
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