Measurement Of Physiological Responses Research Articles

Physical Activity Monitors: Do More Sensors Mean Better Precision?

Physical activity is essential to health. Accelerometry-based activity monitors are widely used in clinical and epidemiological research settings; however, only measuring body movement may prohibit accurate prediction of energy expenditure. Recent technological advancements allow synchronous measurements of heart rate, body temperature, acceleration, and other physiological responses and record them in detail (every minute or finer precision). Current multisensor devices are small, wireless, and capable of continuously recording data over several days or weeks, making them readily applicable in the free-living environment. Future studies should focus on developing strategies to optimize sensor data for accurate and robust predictions of clinically pertinent outcome parameters, such as total daily energy expenditure and physical activity energy expenditure. There is also a need for calibration instruments to allow users to standardize devices in their own laboratory or clinic. We also call for more transparency in publishing sensor properties and modeling algorithms, rather than proprietary or "black-box" prediction approaches.

Bien-être et élevage des porcs

Le développement intensif de la production porcine découle d’une meilleure maîtrise de l’environnement des animaux, d’une prophylaxie des maladies infectieuses, d’une alimentation au plus près des besoins nutritionnels des porcs et d’une sélection génétique orientée vers des performances de croissance et de reproduction optimales. Parallèlement, certaines pratiques se sont avérées défavorables au bien-être du porc. Au cours des dernières décennies la recherche sur le bien-être s’est principalement intéressée aux réponses comportementales et physiologiques au logement, à l’alimentation et à la conduite des animaux. Les résultats ont souligné des difficultés d’adaptation notamment liées à une modification des liens sociaux, une restriction des surfaces individuelles, un appauvrissement du milieu de vie, et des pratiques d’élevage génératrices d’inconfort, de peur ou de douleur. Cette synthèse présente la nature des réponses observées dans ces différentes situations tout en soulignant les voies d’amélioration disponibles pour une meilleure harmonie entre les animaux et leur milieu de vie.

ＮＩＣＵ（新生児集中治療室）の光環境における早産児のストレス評価

The purpose of this study is to evaluate the stress of premature infant, who is hospitalized in the various lightingenvironment of neonatal intensive care unit, by measurement of physiological responses. We measured the electrocardiogram (ECG) and motion of when the lighting environment changes from 31.5±18.1 to 761.8±219.9 [lux]. The subjects were 8 premature infantsthat were the mean corrected gestational age at the time of evaluation was from 32 weeks to 39 weeks. As the results, we confirmedthat premature infants were influenced by lighting environment in each week and obtained the suggestion of possibility that prematureinfant's inhibitory control system for lighting stimuli after the mean corrected gestational age at the time of evaluation was from 36 to37 weeks.

Effect of Aerobic Fitness on the Physiological Stress Responses at Work

The aim of the present study was to examine the effects of aerobic fitness on physiological stress responses experienced by teachers during working hours. Twenty-six healthy female and male teachers aged 33-62 years participated in the study. The ratings of perceived stress visual analogue scale (VAS), and the measurement of physiological responses (norepinephrine, epinephrine, cortisol, diastolic and systolic blood pressure, heart rate (HR), and trapezius muscle activity by electromyography (EMG), were determined. Predicted maximal oxygen uptake (VO(2)max) was measured using the submaximal bicycle ergometer test. The predicted VO(2)max was standardized for age using residuals of linear regression analyses. Static EMG activity, HR and VAS were associated with aerobic fitness in teachers. The results suggest that a higher level of aerobic fitness may reduce muscle tension, HR and perceived work stress in teachers.

The role of biomarkers in the future of drug development

Biomarkers are beginning to be used earlier in drug development, thus allowing the pharmacodynamic effects of targeted therapeutics to be explored before clinical signs and symptoms can be evaluated. This trend will continue and ultimately may enable pharmacodynamic biomarkers to be commonly used to determine therapeutic dosing based on these more accurate measures of human physiological responses. At the same time, biomarkers are also beginning to be used to determine which patients will be likely to respond to the therapeutic, thus avoiding administration to those who will not be likely to benefit. The strategy to achieve these aims and how this can lead to information that can be fed back into drug discovery is described in this perspective.

Occupation, Stress, and Biomarkers: Measuring the Impact of Occupational Injustice

When individuals experience stress due to occupational injustice, neuro-physiological reactions ensue and health states are challenged. Acute and chronic exposure to specific stress hormones and neurotransmitters affect individual occupational capabilities and subsequent occupational trajectories. This article examines the links between health and the human physiologic stress responses to occupation. Based on these findings, neuroendocrine biomarker research is advocated as an effective means of investigating the effects of occupational injustices on health through the quantitative measurement of individual's physiological stress response.

Comparing the physiological and subjective effects of self-administered vs yoked cocaine in humans

Studies with laboratory animals demonstrating different effects of self- vs experimenter-administered drug suggest that the ability to control or predict drug delivery may be an important determinant of drug action. This study assessed whether self-administered and yoked cocaine injections produce different effects in humans. Ten inpatient volunteers with experience in using cocaine participated in a double-blind, yoked design during which four experimental test sessions were conducted. During two sessions, participants controlled if and when up to six 40 mg/70 kg i.v. cocaine injections were given. During two sessions, participants received noncontingent exposure to the same pattern of injections given during the preceding session (i.e., yoked) under blind conditions. Sessions followed a fixed-order, ABAB design. Measures of subjective and physiological response to cocaine were taken throughout each session. Cardiovascular safety parameters were exceeded in some individuals after yoked, but not self-administered, cocaine resulting in some scheduled injections being delayed or withheld. Mean systolic and diastolic blood pressures were higher following yoked compared to self-administered cocaine. In contrast, analysis of the subjective effects revealed only small and generally nonsignificant differences in the effects of self-administered vs yoked cocaine. These results suggest that under the laboratory methods employed, control over the schedule of drug delivery may not alter the subjective effects of cocaine in humans. In contrast, the cardiovascular effects of cocaine appear to be greater when the drug is administered noncontingently.

Alteration of oxidative and carbohydrate metabolism under abiotic stress in two rice ( Oryza sativa L.) genotypes contrasting in chilling tolerance

Abiotic stress is a major limiting factor in crop production. Physiological comparisons between contrasting abiotic stress-tolerant genotypes will improve understanding of stress-tolerant mechanisms. Rice seedlings (S3 stage) of a chilling-tolerant (CT) genotype (CT6748-8-CA-17) and a chilling-sensitive (CS) genotype (INIAP12) were subjected to abiotic stresses including chilling (13/12 degrees C), salt (100mM NaCl), and osmotic (200mM mannitol). Measures of physiological response to the stresses included changes in stress-related sugars, oxidative products and protective enzymes, parameters that could be used as possible markers for selection of improved tolerant varieties. Metabolite analyses showed that the two genotypes responded differently to different stresses. Genotype survival under chilling-stress was as expected, however, CT was more sensitive to salt stress than the CS genotype. The CT genotype was able to maintain membrane integrity better than CS, perhaps by reduction of lipid peroxidation via increased levels of antioxidant enzymes during chilling stress. This genotype accumulated sugars in response to stress, but the accumulation was usually less than in the CS genotype. Chill-stressed CT accumulated galactose and raffinose whereas these saccharides declined in CS. On the other hand, the tolerance mechanism in the more salt- and water-deficit-tolerant CS may be associated with accumulation of osmoprotectants such as glucose, trehalose and mannitol.

Training with inspiratory pressure support in patients with severe COPD

This study evaluates the effects of training with noninvasive ventilatory support in patients with chronic obstructive pulmonary disease in a randomised, controlled, observer-blinded trial. Twenty-nine patients with chronic obstructive pulmonary disease and with a ventilatory limited exercise capacity (forced expiratory volume in one second < 60% predicted, breathing reserve at maximal exercise < 20% of maximally voluntary ventilation, resting arterial oxygen tension > or = 8 kPa (60 mmHg), end-exercise arterial oxygen saturation measured by pulse oximetry > or = 85%) completed an 8-week supervised outpatient cycle exercise programme. Fourteen patients were randomised to training with inspiratory pressure support of 10 cmH2O and 15 patients to training with control (sham) inspiratory pressure support of 5 cmH2O. Outcome measures were the incremental shuttle walking test and a constant-load cycle endurance test at 75% of peak work rate including the measurement of physiological responses, and health status measured using the St. George's Respiratory Questionnaire. Statistically significant between-group differences were found in favour of the inspiratory pressure support of 10 cmH2O group for improvement in shuttle walking distance (16+/-17 versus 3+/-13%), cycle endurance (164+/-124 versus 88+/-128%), and the reduction in minute ventilation during exercise (-11+/-10 versus -2+/-9%). It was concluded that exercise training with inspiratory pressure support of 10 cmH2O resulted in statistically significantly larger improvements in exercise performance than training with inspiratory pressure support of 5 cmH2O in patients with chronic obstructive pulmonary disease suffering from a ventilatory limited exercise capacity. Inspiratory pressure support of 10 cmH2O may be considered as adjunct during high-intensity exercise training.

A new encyclopedic account of plant nutrition: broad, brilliant, but also flawed

In the age of Atkins and the South Beach diet, supermarket shelves overflowing with vitamin and mineral supplements, and an ever-increasing understanding of the link between diet and well-being, development of disease, and lifespan, few would doubt the fundamental importance of nutritional science. Yet, among plant biologists, the study of plant nutrition is considered esoteric and incidental by far too many. It should, of course, be evident that no measurement of biochemical activity, transcript abundance, or physiological response in plants is meaningful without a precise definition of how the organisms or tissue preparations under study were reared and treated nutritionally. For this reason, any modern treatise of the subject area of plant nutrition is a welcome, and necessary, addition to the bookshelves. Two leading authorities, professors E. Epstein and A. J. Bloom, have now added to this limited arsenal with the longawaited second edition of Mineral Nutrition of Plants: Principles and Perspectives. The book is a valuable and thorough, albeit not perfect, account of the field and deserves adoption by libraries, ion transport researchers, and teachers of upperlevel university courses of plant nutrition. The authors are highly acclaimed in the field, and readers benefit in particular from Epsteins’s expertise in basic ion flux analysis and potassium and silicon relations, and Bloom’s strong ecophysiological interests. The book is well written and makes an erudite and ultimately successful case for the fundamental importance of mineral nutrition. A particular strength of the book lies in the thorough historical accounts that accompany each chapter. A clear philosophy penetrates that much is to be learned from experiments conducted by early workers. This approach is refreshing against the matrix of increasingly ahistorical approaches in much of modern science, and the approach is especially appreciated by this referee. Fascinating statistics, examples and analogies abound, and they make for an interesting read in an area that is not considered naturally captivating by many. The book is also attractively illustrated: the blend of representative tables and graphs, micrographs, and technical drawings of plant morphology, postulated ion transport mechanisms, and plant culture systems is above the norm. The breakdown of topics is logical, although the discussion of the roles of individual nutrients and their deficiency symptoms is somewhat disjointed, and details have to be assembled from various chapters. Epstein and Bloom cover basic mineral nutrition, physiol

Fractal correlation structure in fMRI data of rat brain

The raw fMRI data are normally analyzed by statistical methods (Student's t or non-parametric tests) to yield measures of physiological responses. This analysis assumes that successive events in the raw signal are independent (white noise) 1 and hence have a Gaussian distribution. Colored noise if present in the dynamic fMRI data can cause high rate of false positives 2. Such positive correlations have been reported in human fMRI data 1, 2 which are characterized by a spectrum with increasing power toward the low frequencies (1/f pattern). This 1/f pattern can be numerically characterized by a fractal parameter, the Hurst exponent, H. The fMRI experiments of the a-chloralose (40 mg/kg/hr) anesthetized rats (n=12) were conducted on a 4.0 T or 9.4 T spectrometer using a 1 H resonator/surface-coil radio-frequency probe 3 and echo-planar imaging (EPI). Gradient-echo EPI data were acquired with repetition time of 200 ms in matrices of 3232 (4.0 T) and 6464 (9.4 T). Data were collected in vivo and post mortem. Scaled windowed variance (SWV) method 4 was used to calculate the fractal parameter, H and the nearest neighbor correlation coefficient, r1 5 from the fMRI time series. The length of the time series, 4096 scans (4.0 T) and 8192 scans (9.4 T), were adequate for a reliable estimation of H 6. The fMRI data from the 4.0T magnet was dominated by white noise with H=0.530.014. All 9.4 T fMRI time series showed fractional Gaussian noise (fGn) with H>0.5, different from white noise. The H of fGn within its lower and upper bounds of 0 and 1 characterizes the correlation structure itself: with H=0.5 the signal is random, H 0.5 indicates correlation with positive r1 6. Representative Hurst exponent maps obtained in vivo and post mortem were obtained for both 4.0 T and 9.4 T. In vivo cortical and subcortical gray matter regions exhibited much higher values of H (0.730.05) with r1=0.38 than white matter regions (H=0.570.01, r1=0.10). The post mortem results showed a significant (p<0.05) decrease in fractal structure obtained in both gray and white matter regions (H=0.610.03 and H=0.560.03, respectively) and the fractal or colored noise correlation structures were mainly broken in the gray matter regions (r1=0.17). High magnetic field fMRI data reveal fractal patterns across different brain regions. These findings should have implications in fMRI data processing: successive events of the fMRI signal are correlated hence statistical mapping should be used with prior treatment of data, such as creating surrogate time series, which destroys the correlation structure in a time series without the modification of actual values 7.

Psychophysiological Assessment During Exposure in Driving Phobic Patients.

A comprehensive assessment of fear or anxiety requires measurement of both self-report and physiological responses. Respiratory abnormalities have been rarely examined during real-life exposure, although they are an integral part of fear. Twenty-one women with a specific driving phobia and 17 nonphobic women were psychophysiologically monitored during 2 highway-driving sessions; phobic women completed an additional session. Respiratory movements, end-tidal partial pressure of carbon dioxide, an electrocardiogram, skin conductance, and skin temperature were recorded. Phobic patients differed from control participants both physiologically and experientially before, during, and after exposure. Effect size during exposure was large for the authors' measure of hyperventilation. Discriminant analysis indicated that multiple physiological measures contributed nonredundant information and correctly classified 95% of phobic and control participants. Thus, selected respiratory and autonomic measures are valid diagnostic and therapeutic outcome criteria for this situational phobia.

Investigations on dynamic intensity modulated photon fields in radiation therapy

This thesis investigates the validity of inverse algorithms and delivery techniques in dynamic intensity modulated radiation therapy (IMRT) with the view toward clinical implementation. A dosimetric verification technique used to monitor the dynamic beam delivery was introduced with design considerations and clinical evaluation of various quality assurance (QA) phantoms, facilitating the measurement of dynamic IMRT dose distributions and conversion of photon fluence to machine deliverable monitor units. Benchmark tests using thermoluminescent dosimeters (TLDs), solid state detectors, and films were carried out in realistic clinical examples. This was to demonstrate the precision and degree of accuracy of the proposed techniques both in vitro and in vivo systems using canine subjects with paraspinal tumors. The results of the irradiation of canine subjects indicated that the goal of using IMRT to irradiate target volumes with sparing critical structures was met. However, the measure of physiological response found, was incapable of providing a more accurate measure of the dose delivered. Quantitative analysis on the influence of systematic and random field perturbations in highly conformal fields with emphasis on the dosimetric outcome is also presented in this thesis. Two sources of uncertainties deemed important in dynamic therapy of photon beams were studied. These were caused by inaccuracies in velocity and in position of both multileaf collimator (MLC) and backup diaphragms. This was attributed to some degree to the tolerance levels or mechanical constraints of beam defining parameters. These errors were simulated using a Gaussian function with standard deviation of ±1.0 mm to assess changes in dose distribution. Based on the results of this study, QA procedures which are unique to the delivery of dynamic beams were proposed.

Differences in autonomic physiological responses between good and poor inductive reasoners

We investigated individual- and task-related differences in autonomic physiological responses induced by time limited figural and verbal inductive reasoning tasks. In a group of 52 participants, the percentage of correctly responded task items was evaluated together with nine different autonomic physiological response measures and respiration rate (RR). Weighted multidimensional scaling analyses of the physiological responses revealed three underlying dimensions, primarily characterized by RR, parasympathetic, and sympathetic activity. RR and sympathetic activity appeared to be relatively more important response dimensions for poor reasoners, whereas parasympathetic responsivity was relatively more important for good reasoners. These results suggest that poor reasoners showed higher levels of cognitive processing intensity than good reasoners. Furthermore, for the good reasoners, the dimension of sympathetic activity was relatively more important during the figural than during the verbal reasoning task, which was explained in terms of hemispheric lateralization in autonomic function.

Scripted imagery manipulations and smoking cue reactivity in a clinical sample of self-quitters.

The affectively valenced scripts used by S. Tiffany (1990) suggest that different scripts produce relatively equivalent levels of cue reactivity, although it is unclear if these laboratory findings generalize to clinical samples. In this study, cessation-motivated smokers were tested 7 days before they tried to quit smoking and were exposed to 3 audiotaped scripts that depicted different affectively valenced situations (neutral, positive, or negative). The latter 2 scripts also contained smoking cues. The findings using a clinical sample differed considerably from those using analogue laboratory samples across affective, cognitive, and physiological response measures. Reactivity to these standardized scripts failed to predict treatment outcome through a 30-day follow-up. The use of affectively valenced scripts beyond a laboratory sample is questioned.

Integrating the cognitive and physiological aspects of craving.

'Craving is generally considered a significant factor in opiate addiction that is associated with drug-dependence and in relapse to drug use after treatment'-ARC expert consensus (Pickens and Johanson, Drug and Alcohol Dependence 30: 127-131). There are however difficulties in defining craving and urges to use drugs and in associating craving with drug use and relapse. Tiffany [Psychological Review 97(2): 147-168] has reviewed a considerable number of studies that associated reports of craving with consumption measures of drugs and revealed only an overall modest correlation of 0.4. These findings call into question the general assumption that subjective cravings are invariably associated with drug use. Furthermore, it led to Tiffany's provocative argument that cravings are not necessary for drug use. We have addressed these issues by using a range of complementary techniques derived from research in related fields such as the cognitive psychology of anxiety and depression, physiological response measurements and positron emission tomography (PET) neuro-imaging. Initially we developed computerized assessments to probe cognitive dysfunction in addiction that related to biased processing of automatic thoughts and beliefs about craving and drug use in opiate-dependent subjects and alcoholics. Subsequently in an attempt to develop a reliable method of inducing craving we explored an imagery-based technique that relied on the memory of craving experiences. These experiments were conducted both in opiate addicts who had achieved abstinence and in those undergoing detoxification. Finally, we have begun a study to understand the neural mechanisms of craving using imagery-based procedures at the same time as performing PET studies of regional blood flow using the O15-labelled water technique.

The Effects of Music Versus Silence on Measures of State Anxiety, Perceived Relaxation, and Physiological Responses of Patients Receiving Chiropractic Interventions

This study examined the effects of music versus silence on measures of state anxiety, perceived relaxation, and physiological responses of chiropractic patients prior to and immediately following chiropractic treatment interventions. Subjects (N = 30) were randomly assigned to one of 3 conditions. The control group (I) was instructed to relax in silence. The first experimental group (II) listened to a preferred style of music with relaxation instruction. The other experimental group (III) listened to New Age music with deep-breathing visualization relaxation instruction. State anxiety inventory, 10-point Likert tension scale rating, and blood pressure measurements were administered before and after chiropractic procedures for each condition. Additionally, a questionnaire was completed posttreatment. Significant differences (p < .05) were found from pretest to posttest among the 3 groups for state anxiety and the Likert scale ratings for tension. There was no significant difference for physiological measurements across conditions.

Measurement of physiological and psychological responses during exposure to low-frequency whole-body oscillations

Human responses to low-frequency whole-body oscillations were measured using a ship-motion simulator. An electroencephalogram (EEG), an electrocardiogram (ECG), perspiration, face-surface temperature, facial expressions, and the respiration of subjects were measured as physiological effects, and ride quality and motion sickness symptoms as the psychological effects. Before and after exposure to the oscillations, subjects were asked to reply to questionnaire surveys prepared to measure the psychological changes, to take blood samples, and to have blood pressure and sense of balance inspections. Measured results of physiological changes such as EEG, ECG, etc. have been analyzed by means of spectral analysis, wavelet analysis function analysis, and so on. The results of the questionnaire survey of the semantic differential method (SD method) were analyzed by introducing fuzzy integral and fuzzy measures as well as the traditional statistical method. Correlation analyses using all the measured results were carried out. From the results of analyses, it has been made clear that (1) subjects are classified into several types, and (2) psychological effects are important to evaluate the motion sickness incidence and ride quality, for example.

作業者の集中度と周辺照度/作業面照度の比との関係

We compared the concentration of subjects under general illumination, where the ambient illuminance was equal to the task illuminance, with the concentration of subjects under partial illumination, where the ambient illuminance was lower than the task illuminance. The level of concentration of the subjects was evaluated by subjective appraisals, observations of the behavior of the subjects, and measurements of lambda responses (a brain response). The subjective appraisals showed that the subjects found it easiest to concentrate on routine office duties under the general illumination, but they found it easiest to concentrate on more intellectually demanding duties like planning and studying under the partial illumination. Observations of subject behavior and lambda responses measurements clearly showed that the subjects could concentrate better on their work under the partial illumination than they could under the general illumination when they had to do both intellectually demanding duties and just routine office duties. Furthermore, it was confirmed that subjective appraisals, objective evaluations such as observation of subject behavior and measurements of physiological responses are indispensable in evaluating the influence of illumination on the concentration of subjects.

Evaluation of Work Schedules Using Psychophysiological Measures

While the primary goal of this symposium is to demonstrate the utility of psychophysiological measures in the evaluation of work schedules, the more general goal is to promote the use of psychophysiological measures in organizational design and management research. There are several good reasons to include psychophysiological measures in ergonomic evaluations. Foremost among these is that the information provided about worker well-being and performance capabilities cannot be obtained in other ways. Psychophysiological measures provide continuous, non-invasive, and objective measurement of an individual's response to work activities. Because of known relationships between physiological mechanisms and behavior, work-induced changes in physiological response can be used to monitor the effects of organizational design on work demand or recovery. Most would agree, however, that psychophysiological measures are seldom meaningful unless they are collected and analyzed in conjunction with other measures. In particular, psychophysiological measures can provide crucial information about worker well-being when subjective reports of distress or discomfort are biased by psychosocial factors, and also when workers compensate for increases or decreases in work demand by drawing on reserve capacity. In cases where performance measures or subjective reports are more reliable, measurement of psychophysiological responses can provide convergent results that add to the scientific validity of the research investigation. This explains why all researchers in this symposium use a balanced approach and analyze performance and/or subjective ratings in combination with psychophysiological measures. Beyond the scientific rationale for including psychophysiological measures in ergonomics research, many of the practical difficulties researchers faced in the past have been eliminated by recent technological advances. Modern heart rate monitoring systems, for example, have noise suppression features that improve signal quality and allow data collection in real work settings. Portable data loggers enable researchers to monitor multiple physiological response measures over 24-hour periods. Handling large data sets is no longer a problem because the digital storage capability of small computers is nearly unbounded. Data analysis software, such as time series analysis, has become more sophisticated and easier to use. What all this means in practical terms is that it is no longer necessary to dedicate a major portion of one's career to surmount the technical problems associated with psychophysiological research. The wide range of work scheduling topics covered in this symposium is a good example of the utility of psychophysiological measures in ergonomics research. Specific work scheduling topics include: appropriate rest break length at different times of the work day to ensure adequate recovery from sustained cognitive demand (Boucsein and Thum), methods for verifying the health and safety of underground miners working 12-hour shifts in shortened work weeks (Duchon and Smith), the impact of self-managed rest breaks on well-being during continuous computer work (Henning, Callaghan, Guttman, and Braun), and how assessing work efficiency during a cognitive task can be used to evaluate the effectiveness of work/rest schedules (Meijman). While the specific goals of these studies may differ, in each case the use of psychophysiological measures enhances the scientific validity of the research and provides important information about the relationship between work schedule design and worker well-being.