Design, Evaluation, and Application of Heart Rate Variability Analysis Software (HRVAS)

The analysis of heart rate variability (HRV) has become an increasingly popular and important tool for studying many disease pathologies in the past twenty years. HRV analyses are methods used to non-invasively quantify variability within heart rate. Purposes of this study were to design, evaluate, and apply an easy to use and open-source HRV analysis software package (HRVAS). HRVAS implements four major categories of HRV techniques: statistical and time-domain analysis, frequency-domain analysis, nonlinear analysis, and time-frequency analysis. Software evaluations were accomplished by performing HRV analysis on simulated and public congestive heart failure (CHF) data. Application of HRVAS included studying the effects of hyperaldosteronism on HRV in rats. Simulation and CHF results demonstrated that HRVAS was a dependable HRV analysis tool. Results from the rat hyperaldosteronism model showed that 5 of 26 HRV measures were statistically significant (p\u3c0.05). HRVAS provides a useful tool for HRV analysis to researchers

Cardiac Autonomic Control in Patients with Metabolic Syndrome

Metabolic syndrome (MetS) encompasses metabolic abnormalities that substantially increase risk for chronic illnesses. MetS and stress are closely related; the pathophysiology of MetS involves dysregulated stress response in both the physiological and psychological domains. In an effort to further clarify the relationship between metabolic abnormalities and autonomic dysregulation, we used ambulatory impedance cardiography to examine indicators of cardiac autonomic control (CAC) in a sample of 50 adult primary care patients with and without MetS. Indices of sympathetic and parasympathetic influences on cardiovascular functioning were assessed in the context of psychological stressors and compared across experimental groups and examined in relation to self-reported health measures. Primary results suggest that while our experimental groups did not differ significantly on baseline measures, patterns of responses to experimentally induced stressors were largely consistent with our predictions, and demonstrate that individuals with MetS responded to stress cues with more maladaptive CAC scores. Moreover, in line with previous work, we found that elements of CAC in our sample were predictive of both cardiovascular disease and self-reported environmental quality of life. Overall, our results suggest that maladaptive physiological manifestations of the stress response are evident among individuals with MetS and may also be related to long-term health outcomes. The present study carries implications for both evaluation and assessment as well as treatment delivery and monitoring. In addition, the ambulatory nature of data collection demonstrated here supports trends toward mHealth and related initiatives in emerging modes of healthcare delivery

AN INITIAL EVALUATION OF IBI VIZEDIT: AN RSHINY APPLICATION FOR OBTAINING ACCURATE ESTIMATES OF AUTONOMIC REGULATION OF CARDIAC ACTIVITY

Photoplethysmogram (PPG) sensors are increasingly used to collect individual heart rate data during laboratory assessments and psychological experiments. PPG sensors are relatively cheap, easy to use, and non-invasive alternatives to the more common electrodes used to produce electrocardiogram recordings. The downside is that these sensors are more susceptible to signal distortion. Often, the most relevant measures for understanding psychological processes that underlie emotions and behaviors are measures of heart rate variability. As with all measures of variability, outliers (i.e., signal artifacts) can have outsized effects on the final estimates; and, given that these scores represent a primary variable of interest in many research contexts, the successful elimination of artefactual points is critical to the ability to make valid inferences with the data. Prior to the development of IBI VizEdit, there was no single, integrated processing and editing pipeline for PPG data. The present pair of studies offers and initial evaluation of the program’s performance. Study 1 is focused on the efficacy of a novel approach to imputing sections of particularly corrupted PPG signal. Study 2 tests the ability of trained editors to reliably use IBI VizEdit as well as the validity of estimates of cardiac activity during a prescribed set of laboratory tasks. Study 1 suggests that the novel imputation approach, under certain conditions and using certain parameterizations may hold promise as a means of accurately imputing missing sections of data. However, Study 1 also clearly demonstrates the need for further refinement and the consideration of alternative implementations. The results from Study 2 indicate that IBI VizEdit can be reliably used by trained editors and that estimates of cardiac activity derived from its output are likely valid

Performance Under Pressure: Examination of Relevant Neurobiological and Genetic Influence

Satisfactory human performance demands the complex interaction of multiple factors such as arousal/motivation, emotion expression and regulation, intricate synchronization of central and peripheral motor processes, all recruited in the service of adaptive, moment to moment decision making. The segregation of these various factors aids in the understanding of their complex interactions. Recently, scientific investigation has focused on understanding the integration of these various factors. The complementary role of emotion and cognition in successful human performance is emphasized. As a viable metric of emotion regulation differences in asymmetry of human brain frontal activity have traditionally been utilized to index certain trait predispositions within the approach/withdrawal dimension of emotion/motivation. Researchers have begun to make a case for an acute or state difference in frontal asymmetry. This "Capability Model" posits the neural underpinnings of the relative difference in electrical activity between the left and right frontal lobes as a phasic/situational mechanism possibly sub-serving the integration of emotion and cognition during challenge. The current study demonstrates support for this situational/state model of frontal asymmetry. Thirty channels of EEG were collected along with, skin conductance, heart rate and acoustic startle amplitudes while subjects were engaged in two levels of a working memory task under three increasing levels of stress (final level=electric stimuli/shock). Hierarchical regression results implicate state frontal asymmetry differences as having a mediating role in the adaptive regulation of emotion during enhanced performance on an N-back working memory task but only in the high stress condition. During shock /threat of shock participants with higher state asymmetry scores showed significant attenuation of eye-blink startle magnitudes, faster reaction times and increased accuracy. This suggests an integration of emotion and cognition

Investigation of the effects of transcutaneous electrical stimulation on physiological stress, marksmanship, and cognitive performance

Military training and operations can place significant demands on cognitive and physical resources of service members, resulting in heightened stress and fatigue, elevated risk of accidents and injuries, and diminished cognitive and occupational performance. Transcutaneous electrical stimulation (TES) is a novel, non-invasive neuromodulatory technique being investigated as a means to improve alertness and preserve performance under stress with few-to-no side effects. Despite the recent increase in research using TES, few studies have explored the effects of stimulation of the trigeminal nerve on cognition and the human stress response. Therefore, the aims of this study were to elucidate the effects of TES on biochemical and physiological responses to stress, cognition, and marksmanship performance under cognitive load. Participants in this repeated measures, crossover-design study included 23 healthy male (n = 18) and female (n = 5) civilians and members of the military ranging in age from 19 to 37 (mean 24.00 ± 5.65) years. Study procedures occurred in the afternoon on five consecutive days, including two testing days involving administration of active or sham TES to the right supraorbital region of the face using a commercially-available device (Thync One, Cerevast Therapeutics). To evaluate the effects of TES on the stress response, participants were required to complete a prolonged, cognitively challenging target discrimination task using a simulated firing range, which has been previously demonstrated to induce a reliable stress response in human research volunteers. Computer-assisted cognitive tasks were administered before and after rifle marksmanship in order to provide complementary assessment of functional domains challenged during the marksmanship task. Salivary markers of cortisol and α-amylase were collected at several time points during the testing day, and electrocardiography (ECG) and photoplethysmography (PPG), both markers of heart rate variability and stress responding, were monitored continuously. Linear mixed models with random slopes were used to analyze the effect of stimulation condition (active versus sham TES) on marksmanship and cognitive, physiological, and salivary outcomes across the testing period and at each measurement time point. No significant effects of stimulation condition or the interactions between stimulation condition and measurement time point were found for salivary stress biomarkers (punadj range 0.12 – 0.98) or for cognitive (punadj range 0.25 – 0.88) and physical workload (punadj range 0.31 – 0.79). There were no significant effects of stimulation condition on time-series indicators of heart rate variability (punadj range 0.10 – 0.96) except for pNN50 when measured with PPG (β = -4.97, punadj = 0.04, padj = n.s., d < 0.01). There were, however, significant stimulation condition by time interaction effects on mean heart rate, mean R-R interval, SDNN, RMSSD, and pNN50 (punadj range 0.12 – 0.98, d range < 0.01 – 0.02), indicating that trigeminal TES using the Thync One device increased activity of both the sympathetic and parasympathetic nervous systems during marksmanship and cognitive testing. Similar effects were noted on frequency-series indicators of heart rate variability using both ECG and PPG, in which stimulation condition effects were noted on ECG high frequency absolute (β = 8.50, punadj < 0.01, padj = 0.01, d < 0.01) and relative powers (β = -8.54, punadj < 0.01, padj = 0.01, d < 0.01), as well as PPG very low frequency power (β = -367.98, punadj < 0.01, padj = n.s., d = 0.12). Effects of the interaction between stimulation condition and measurement time point were noted on very low, low, and high frequency powers (punadj range < 0.01 – 0.048, d range < 0.01 – 0.21), as well as the ratio of low- to high-frequency powers in ECG (punadj range < 0.01 – 0.048, d < 0.01 for all). These results also suggest that trigeminal TES increased activity of both the sympathetic and parasympathetic nervous systems during marksmanship and cognitive testing. Furthermore, significant effects of stimulation condition were noted on marksmanship shot accuracy (β = 0.14, punadj = 0.01, padj = n.s., d = 0.60) and distance of shots from the targets’ center of mass (β = -0.08, punadj = 0.02, padj = n.s., d = 0.56), indicating that trigeminal TES impaired shot accuracy. There were also significant condition-by-time interaction effects on target detection latency (β = 220.46, punadj = 0.04, padj = n.s., d = 0.49); significant impairments in shot latency observed during the first marksmanship session in the active TES condition only resolved by the second marksmanship session. There were no significant effects of TES on accuracy or response times for neuropsychological tasks assessing response inhibition, sustained attention, and working memory (punadj range 0.09 – 0.98). Active trigeminal TES did, however, significantly reduce the standard deviation of response times on a measure of sustained attention and response inhibition (β = -16.29, punadj = 0.045, padj = n.s., d = 0.43). Although the literature suggests that TES may benefit stress and performance, these results do not support that conclusion. Overall, these analyses found that TES using a commercially available device did not influence chemical biomarkers of stress, but did influence markers of physiological stress, as well as cognitive and marksmanship performance under high cognitive load. TES was associated with impairments in marksmanship performance as well as increases in both sympathetic and parasympathetic nervous system activity. Further studies using different stimulation parameters, including multiple sessions of stimulation, will be necessary to more fully characterize possible influences of trigeminal nerve stimulation on stress responding and marksmanship performance or other military relevant tasks. In addition, this project underscores the need for more investigation into the mechanisms of effect of the Thync One device and other devices applying TES of the trigeminal nerve

The Healthy Staff Initiative Study: Examining Exercise, Health Coaching, and Mindfulness Meditation for University Employees: A Randomized Trial

Objective: This study evaluated the effectiveness of workplace interventions for university employees aimed at increasing overall fitness. Investigators examined the benefits of a workplace walking program (WP), health coaching (HC) and a mindfulness meditation program (WPHC+MM) combined vs. a program where subjects solely received the workplace walking program and health coaching (WPHC). Methods: Sixty employees from the York University, Keele Campus volunteered for participation. They were randomly assigned to one of the two 24 week programs. The weekly workplace walking program and health coaching (WPHC) was provided to both groups for the first 12 weeks and MM participation was additionally facilitated for the comparison WPHC+MM group 3 times per week for the first 12 weeks. For the remaining 12 weeks, both groups received no further structural support in terms of walking schedule or HC sessions. Participants were assessed at baseline, 3 months and 6 months on fitness measures, psychological questionnaires, and heart rate variability. Results: The study sample included 93% women and 80% of participants were 40 years of age or older. At baseline the mean waist circumference (WC) was 88.0 cm, mean BMI was 26.74 kg/m2, mean weight was 71.9 kg and the mean pulse/blood pressure were 73 bpm and 122/76 mmHg respectively. Forty-seven participants were analyzed: n=22 in the WPHC+MM and n=25 for WPHC. Repeated measures ANOVA were conducted. A main effect of time analysis indicated: significant increases in VO2 peak: F(2,80)= 9.138, p=0.001, partial 2= 0.186; significant increases in Five Facet Mindfulness Questionnaire (FFMQ): F(2,90)=5.997, p=0.004, partial 2=0.118; a significant decrease over time on the perceived stress scale (PSS) (F(2,90)=3.857 units, p=0.033, partial 2=0.079) and a significant decrease over time in perceptions of overall job commitment: F(2,90)=6.158, p=0.004, partial 2=0.120. Conclusion: This study found that a workplace walking (WP), health coaching (HC) and a mindfulness meditation program (WPHC+MM) was not superior to solely walking and health coaching (WPHC) program. By study completion, employees overall, demonstrated improvements in their cardiovascular fitness/ aerobic endurance, in overall mindfulness, in perceived stress (decreases) and in perceptions of job over-commitment (decreases) when compared to the baseline assessments

Modern Telemetry

Telemetry is based on knowledge of various disciplines like Electronics, Measurement, Control and Communication along with their combination. This fact leads to a need of studying and understanding of these principles before the usage of Telemetry on selected problem solving. Spending time is however many times returned in form of obtained data or knowledge which telemetry system can provide. Usage of telemetry can be found in many areas from military through biomedical to real medical applications. Modern way to create a wireless sensors remotely connected to central system with artificial intelligence provide many new, sometimes unusual ways to get a knowledge about remote objects behaviour. This book is intended to present some new up to date accesses to telemetry problems solving by use of new sensors conceptions, new wireless transfer or communication techniques, data collection or processing techniques as well as several real use case scenarios describing model examples. Most of book chapters deals with many real cases of telemetry issues which can be used as a cookbooks for your own telemetry related problems

Life Sciences Program Tasks and Bibliography

This document includes information on all peer reviewed projects funded by the Office of Life and Microgravity Sciences and Applications, Life Sciences Division during fiscal year 1995. Additionally, this inaugural edition of the Task Book includes information for FY 1994 programs. This document will be published annually and made available to scientists in the space life sciences field both as a hard copy and as an interactive Internet web pag

CEPS: An Open Access MATLAB Graphical User Interface (GUI) for the Analysis of Complexity and Entropy in Physiological Signals

Background: We developed CEPS as an open access MATLAB® GUI (graphical user interface) for the analysis of Complexity and Entropy in Physiological Signals (CEPS), and demonstrate its use with an example data set that shows the effects of paced breathing (PB) on variability of heart, pulse and respiration rates. CEPS is also sufficiently adaptable to be used for other time series physiological data such as EEG (electroencephalography), postural sway or temperature measurements. Methods: Data were collected from a convenience sample of nine healthy adults in a pilot for a larger study investigating the effects on vagal tone of breathing paced at various different rates, part of a development programme for a home training stress reduction system. Results: The current version of CEPS focuses on those complexity and entropy measures that appear most frequently in the literature, together with some recently introduced entropy measures which may have advantages over those that are more established. Ten methods of estimating data complexity are currently included, and some 28 entropy measures. The GUI also includes a section for data pre-processing and standard ancillary methods to enable parameter estimation of embedding dimension m and time delay τ (‘tau’) where required. The software is freely available under version 3 of the GNU Lesser General Public License (LGPLv3) for non-commercial users. CEPS can be downloaded at https://bitbucket.org/deepak_panday/ceps/src/pipeline_v2/. In our illustration on PB, most complexity and entropy measures decreased significantly in response to breathing at 7 breaths per minute, differentiating more clearly than conventional linear, time- and frequency-domain measures between breathing states. In contrast, Higuchi fractal dimension increased during paced breathing. Conclusions: We have developed CEPS software as a physiological data visualiser able to integrate state of the art techniques. The interface is designed for clinical research and has a structure designed for integrating new tools. The aim is to strengthen collaboration between clinicians and the biomedical community, as demonstrated here by using CEPS to analyse various physiological responses to paced breathing