Predictability of individual differences in activation processes in a field setting based on laboratory measures

Children's, Adolescents', and Young Adults' Heart Rate Reactivity to, and Recovery from, a Brief Psychological Stressor

Heart rate reactivity to a 2 minute mental arithmetic stressor delivered under timed and competitive conditions and graded for age-related difficulty was collected on 148 males and 153 females grouped into five age cohorts ranging from 7 to 20 years. Data on resting heart rate, heart rate during the stressor period, and post-stressor recovery showed significant sex (females had higher heart rates) and age effects (there was a general decrease in heart rate with age). There were no significant interactions between age and sex. Mean heart rate reactivity also showed significant variation with age, but no significant differences between males and females, nor any significant interaction between age and sex. The age effect for heart rate reactivity appeared to be a result of the oldest age group having significantly greater increases in heart rate than all other age groups.

Development of a multi-channel exploratory battery for psychophysiological assessment: the Stress Profile

OBJECTIVE

As the expanding field of psychophysiology is currently demanding applied methodologies to be used in the clinic, this study aimed to develop a practical multi-channel exploratory battery for psychophysiological evaluation of stress (the Psychophysiological Stress Profile; PSP). The PSP records 6 psychophysiological variables and it is designed to be mainly used in the daily clinic. Moreover, the PSP was intended to be 'the method' to obtain normative and individual psychophysiological patterns, providing relevant information for the therapeutic process.

METHODS

Two hundred and three subjects were evaluated with the PSP in two different contexts: the natural environment and the laboratory. Factorial analysis was applied to obtain psychophysiological profiles. These profiles are based on the covariation among different system responses. The Burt and Tucker Congruence Coefficient was used to compare factorial structures.

RESULTS

A 3-factor structure was obtained in both contexts, Congruence Coefficient indicates that these factorial structures are very similar, indicating the existence of a unique and consistent psychophysiological pattern that characterizes the sample.

CONCLUSIONS

The identified factorial structure shows relevant activation patterns, offering a comprehensive view of the subject's functioning. The structure is consistent through samples and can be considered as normative data for the studied population. PSP has turned out to be a quick and easy-to-use psychophysiological battery that has shown adequate internal consistency for all the recorded variables. In this way, the PSP methodology shows its practical value and usefulness in the assessment process.

The somatic symptom paradox in DSM-IV anxiety disorders: suggestions for a clinical focus in psychophysiology

Although DSM-IV criteria for anxiety disorders include physiological symptoms, these symptoms are evaluated exclusively by verbal report. The current review explores the background for this paradox and tries to demonstrate on theoretical and empirical grounds how it could be resolved, providing new insights about the role of psychophysiological measures in the clinic. The three-systems approach to evaluating anxiety argues that somatic measures as well as verbal and behavioral ones are indispensable. However, the low concordance between these domains of measurement impugns their reliability and validity. We argue that concordance can be improved by examining the relationship of variables less global than anxiety and by restriction to specific anxiety disorders. For example, recent evidence from our and other laboratories indicate a prominent role of self-reported and physiologically measured breathing irregularities in panic disorder. Nonetheless, even within a diagnosis, anxiety patients vary radically in which somatic variables are deviant. Thus, in clinical practice, individual profiles of psychological and physiological anxiety responses may be essential to indicate distinct therapeutic approaches and ways of tracking improvement. Laboratory provocations specific to certain anxiety disorders and advances in ambulatory monitoring vastly expand the scope of self-report and physiological measurement and will likely contribute to a refined assessment of anxiety disorders.

Psychosocial stress-induced heart rate reactivity and atherogenesis: cause or correlation?

The relationship between heart rate reactivity and atherogenesis is examined. Data from empirical studies are presented which support theoretical suggestions that it is the heart rate itself rather than the increase in heart rate following the onset of a stressor which is causally related to the development of arterial atherosclerosis. Several directions for research which will clarify this issue are discussed, with recent developments in the detection of atherosclerosis suggested as forming the basis of more reliable investigation of the effects of cardiac output variables upon arterial atherogenesis.

Stability of cardiovascular responses across subjects and situations: a systematic approach

This study describes the reproducibility of behaviorally elicited cardiovascular response patterns, 111 subjects were studied over a 1-year interval. Physiological variables recorded were heart rate, systolic and diastolic blood pressure, and respiratory rate. Test-retest stability coefficients were calculated and compared with the results of a study with a 3-day interval between test sessions. The physiological data are depicted in a four-dimensional data box (subjects, situations, replications, variables), and the variance components of the factors and their interactions are estimated. Some of the interaction components are associated with specificity principles and with temporal stability. To comprehensively describe special aspects of stability, measures for stability were generated (concerning subjects, situations, or both), adopting basic ideas from the covariance partitioning approach. The stability measures were compared with simple test-retest reliability coefficients and with generalizability coefficients, and systematic relationships between the stability measures are discussed.

Maintenance and generalizability of laboratory-based heart rate reactivity control training

The maintenance over time (4 months) and generalizability (to a work setting) of laboratory-based heart rate reactivity control training was investigated. Forty-three subjects received 5 weeks of biofeedback, imagery, and breathing training and 41 subjects acted as controls. Although there were no significant differences between the reactivities of the control and those of the treatment subjects at any of three pretraining tests, significant differences were noted immediately following training, 7 weeks, and 4 months later, showing maintenance effects. Data collected during work activities on the frequency of reactivity of a magnitude similar to that in the laboratory also showed that treatment subjects had significantly fewer incidents of reactivity than control subjects after training. Followup interviews with treatment subjects indicated that lifestyles were also enhanced in a variety of areas, suggesting that the training had wider benefits. Issues for further research are discussed.

Social neuroscience: autonomic, neuroendocrine, and immune responses to stress

The immune system is influenced by central nervous system processes that are shaped by social and psychological factors. Considerations of social factors, intrapersonal process, and autonomic psychophysiology therefore may contribute to a fuller understanding of both immune and brain function. Research reviewed here (a) examines the socioemotional factors that contribute to, or moderate, responses to brief and chronic stressors, (b) determines whether or not stable individual differences in heart rate reactivity predict neuroendocrine and immune responses to a brief psychological stressor and to an influenza virus vaccine, and (c) investigates the autonomic origins of individual differences in low and high heart rate reactivity and their relationship to neuroendocrine and immune responses to chronic and acute stressors. Among our findings are: (a) acute psychological stressors activate the sympathetic adrenomedullary system across individuals and affect immune function; and (b) individuals characterized by high sympathetic cardiac reactivity to acute psychological stressors also show a relative activation of the hypothalamic pituitary adrenocortical system and altered immune function.

Myocardial and peripheral vascular responses to behavioral challenges and their stability in black and white Americans

The purpose of this study was to assess the short term stability of myocardial and peripheral vascular responses to behavioral challenges, and to compare the response patterns of Black and White men. Blood pressure and heart rate, as well as stroke volume, cardiac output, total peripheral resistance, and systolic time interval measures derived from the impedance cardiogram were obtained in 12 Black and 12 White men. These measures were taken prior to and during an evaluative speech stressor, a mirror star tracing task, and a forehead cold pressor test presented during two laboratory sessions scheduled two weeks apart. In general, total peripheral resistance and impedance-derived baseline measures showed acceptable reproducibility (G greater than .85). With a few exceptions, adequate reliability was also demonstrated for change (delta) scores. All tasks raised blood pressure responses above resting levels. Blacks demonstrated significantly greater increases in total peripheral resistance responses across tasks. Whites but not Blacks also revealed increases above baseline in cardiac output and contractility as estimated by the Heather Index. These findings are consistent with the view that Blacks show greater vascular responsiveness than Whites across a variety of tasks, but reveal less myocardial responsiveness.

Incidence of laboratory-based heart rate reactivity during typical daily events

Heart rate reactivity to a standardized laboratory stressor (mental arithmetic under timed and competitive conditions) was measured in 37 men and women, drawn from white- and blue-collar occupations. In addition, heart rate reactivity data during 4 hr of work were gathered on each of these subjects and analyzed to determine (1) the presence during work time of reactivity equal to or greater than that to the mental arithmetic stressor; (2) the incidence of reactivity of 5, 10, 15, and 20 bpm during work time, and (3) the predictability of frequency of work time reactivity by mental arithmetic reactivity. Data suggested that, although there were several incidences of heart rate reactivity responses during work which were similar to those noted in the laboratory, these work heart rate responses were not able to be significantly predicted by laboratory heart rate responses.

The reliability and specificity of delta versus residualized change as measures of cardiovascular reactivity to behavioral challenges

The statistical parameters that influence the reliability of delta and residualized change were examined in the context of the assessment of cardiovascular reactivity. A comparison of the relative reliabilities of these two quantification methods was performed using systolic blood pressure, diastolic blood pressure, and heart rate data from two samples of 134 and 109 subjects observed during baseline and either two or four behavioral challenges. The results indicated that both delta and residualized change scores can yield reliable measures of blood pressure and heart rate reactivity to behavioral challenges, and that their reliabilities will be comparable under the conditions observed in laboratory reactivity studies. Correlations between baseline and delta did not indicate that these two measures were systematically related. Finally, delta scores are more appropriate than residuals when assessing the generalizability of responses across a variety of tasks.

Motor imagination--a model for motor performances?

The effect of training competition (TC) on central nervous activation was investigated in order to examine whether motor imagination could serve as a model for complex motor skills concerning information processing and motor control. EEG was recorded before and immediately after the TC. The mean alpha frequency (MAF) was computed from the EEG power density spectra. A significant increase of MAF was found after the TC. Similar changes were found during motor imagination. Thus, motor imagination seems to be a good model to examine activation processes.

Cardiovascular Reactivity Evoked by Means of Psychological and Physical Stressors

Cardiovascular effects of several physical and psychological stressors were investigated. Indirect continuous blood pressure as well as heart-rate were recorded. Systolic, diastolic, and mean blood pressure as well as heart-rate were recorded. Different patterns of cardiovascular activation during different stressors were obtained. The Valsalva manoeuvre evoked a basic negative feedback baro-receptor response. Physical exercise (bicycle ergometer stress) evoked an overriding of the baro-reflex sympathetic stimulation to fulfil metabolic needs. Psychological stressors such as a TV-game (‘space invaders’), a binary choice program and mental arithmetic produced a pattern of autonomic nervous stimulation which can be described as extra-metabolic or psychophysiological. Possible differences in reaction patterns between psychological stressors are discussed in the light of a literature study. ‘Active’ and ‘passive’ coping may be of importance.

Dynamics of central nervous activation during motor imagination

Central nervous processes of sensorimotor and behaviour control are prerequisites of skills and motor performance. Eight students (Ss) in sports were tested during motor imagination. They were requested to imagine their own movements when swimming over a distance of 100 m (sitting in a resting position, without any real or imitated movements). Electroencephalograms (EEG), heart rate (HR), skin conductance (SC), and respiration rate (RR) were recorded before, during and after one series of 3 periods of mental training (MT). HR, RR and SC increased during MT. The highest level of SC can be found at the beginning of the first period of imagination. Mean alpha-frequency of the EEG over the left occipital and precentral area in all Ss was higher during MT. The degree of these changes varied during the 3 imagination periods.

Methodological guidelines for impedance cardiography

Impedance cardiography was introduced over 20 years ago as a noninvasive and unobtrusive technique for measuring systolic time intervals and cardiac output. Although our understanding of the physiological events reflected in the impedance cardiogram has become more refined, the technique's theoretical basis remains somewhat controversial and acceptance of its validity has relied heavily upon empirical validation. Largely as a consequence of this status, there have been inadequate grounds on which to develop sound methodological standardization. Currently, the methodological approaches that have been most frequently adopted may be viewed as representing the standard. The various aspects of impedance methodology are discussed, and alternative approaches described, with the objective of providing an informed basis for choosing among these methodological alternatives. It is recommended that studies utilizing impedance cardiography should be reported with clear and detailed methodological description. This should help clarify the extent to which methodological differences may underlie any discrepant research observations, as well as facilitate the emergence of improved methodological standards.

Individual differences in heart rate response during behavioral challenge

This program of experiments examined heart rate responses to mental arithmetic and a video game. Attention first focused on their metabolic relevance. Comparison with heart rate/oxygen consumption regression equations generated from isotonic exercise data revealed that the heart rate increases of certain individuals were considerably in excess of those necessitated by contemporary metabolic demand. Both temporal and intertask consistency of reaction were explored, and supportive evidence was obtained. The relationship between laboratory and real-world reactions was investigated, and preliminary evidence found suggesting that in-laboratory responses are indicative of responses to more naturalistic stressors. Finally, twin studies examining the genetic and environmental determinants of individual differences in heart rate change during the tasks revealed a substantial genetic component for these responses.

Biological bases of childhood shyness

The initial behavioral reaction to unfamiliar events is a distinctive source of intraspecific variation in humans and other animals. Two longitudinal studies of 2-year-old children who were extreme in the display of either behavioral restraint or spontaneity in unfamiliar contexts revealed that by 7 years of age a majority of the restrained group were quiet and socially avoidant with unfamiliar children and adults whereas a majority of the more spontaneous children were talkative and interactive. The group differences in peripheral physiological reactions suggest that inherited variation in the threshold of arousal in selected limbic sites may contribute to shyness in childhood and even extreme degrees of social avoidance in adults.

Activation in professional ballet dancers

The purpose of the study was to examine professional ballet dancers' psychophysiological activation in different types of rehearsal and performance. Electrical activity of the trapezius muscle (EMG), blood pressure, heart rate, and skin conductance level were measured. Self-estimated mental tension was evaluated, as was success in the performance. The effect of sex, age, professional experience, artistic status, role, and type of rehearsal and performance was studied. Principals had lower EMG at rest than soloists or corps de ballet dancers. The principals' psychophysiological activation during performance was increased more than that of soloists or corps de ballet dancers as compared to the values at rest. The type of performance had an effect on self-estimated mental tension and psychophysiological responses. During the last general rehearsals (with an audience) physiological activation was higher than on first nights or in other performances or rehearsals.

Psychophysiological assessments in a repeated-measurement design extending over a one-year interval: trends and stability

Intra-individual variability in psychophysiological parameters of activation processes can be attributed to functional fluctuation and/or error of measurement. A repeated measurement design at intervals of about three weeks, three months and one-year duration, in which a laboratory-field comparison was made with respect to predictability of individual differences, provided data on a broad spectrum of physiological and psychological variables measured under various conditions. We investigated the reproducibility of commonly used laboratory measures in a sample of male students of physical education (N = 58). Results indicate that a hypothetical general trend component accounts for less than 10 percent of the total variance in a two-factorial ANOVA (Subjects X Replications). Stability coefficients based on raw scores (rest and strain scores) are relatively higher than those based on change scores. Stability of heart rate, pulse wave velocity, respiration rate during rest, mental arithmetic and cold pressor test and cardiovascular and respiratory parameters during ergometer exercise and 1000m run exceed the stability of blood pressure, parameters from impedance cardiography, eye blink and electrodermal activity during the respective laboratory conditions. The implications of such descriptive studies for the planning and evaluation of longitudinal studies and for selection of parameters depicting habitual dispositions in differential psychophysiological research are indicated.