Dissociated autonomic regulation during stress and physical complaints

Predicting response to stepped-care cognitive behavioral therapy for insomnia using pre-treatment heart rate variability in cancer patients

OBJECTIVE

This study examined whether high frequency heart-rate variability (HF-HRV) and HF-HRV reactivity to worry moderate response to cognitive behavioural therapy for insomnia (CBT-I) within both a standard and stepped-care framework among cancer patients with comorbid insomnia. Biomarkers such as HF-HRV may predict response to CBT-I, a finding which could potentially inform patient allocation to different treatment intensities within a stepped-care framework.

METHODS

177 participants (86.3 % female; Mage = 55.3, SD = 10.4) were randomized to receive either stepped-care or standard CBT-I. 145 participants had their HRV assessed at pre-treatment during a rest and worry period. Insomnia symptoms were assessed using the Insomnia Severity Index (ISI) and daily sleep diary across five timepoints from pre-treatment to a 12-month post-treatment follow-up.

RESULTS

Resting HF-HRV was significantly associated with pre-treatment sleep efficiency and sleep onset latency but not ISI score. However, resting HF-HRV did not predict overall changes in insomnia across treatment and follow-up. Similarly, resting HF-HRV did not differentially predict changes in sleep diary parameters across standard or stepped-care groups. HRV reactivity was not related to any of the assessed outcome measures in both cross-sectional and longitudinal analyses.

CONCLUSION

Although resting HF-HRV was related to initial daily sleep parameters, HF-HRV measures did not significantly predict longitudinal responses to CBT-I. These findings suggest that HF-HRV does not predict treatment responsiveness to CBT-I interventions of different intensity in cancer patients.

ComEDA: A new tool for stress assessment based on electrodermal activity

Non-specific sympathetic arousal responses to different stressful elicitations can be easily recognized from the analysis of physiological signals. However, neural patterns of sympathetic arousal during physical and mental fatigue are clearly not unitary. In the context of physiological monitoring through wearable and non-invasive devices, electrodermal activity (EDA) is the most effective and widely used marker of sympathetic activation. This study presents ComEDA, a novel approach for the characterization of complex dynamics of EDA. ComEDA overcomes the methodological limitations related to the application of nonlinear analysis to EDA dynamics, is not parameter-sensitive and is suitable for the analysis of ultra-short time series. We validated the proposed algorithm using synthetic series of white noise and 1/f noise, varying the number of samples from 50 to 5000. By applying our approach, we were able to discriminate a statistically significant increase of complexity in the 1/f noise with respect to white noise, obtaining p-values in the range [4.35 × 10-6, 0.03] after the Mann-Whitney test. Then, we tested ComEDA on both EDA signal and its tonic and phasic components, acquired from healthy subjects during four experimental protocols: two inducing a sympathetic activation through physical efforts and two based on mentally stressful tasks. Results are encouraging and promising, outperforming state of the art metrics such as the Sample Entropy. ComEDA shows good performance not only in discriminating between stressful tasks and resting state (p-value < 0.01 after the Wilcoxon non-parametric statistical test applied to EDA signals of all the four datasets), but also in differentiating different trends of complexity of EDA dynamics when induced by physical and mental stressors. These findings suggest future applications to automatically detect and selectively identify threats due to overwhelming stress impacting both physical and mental health or in the field of telemedicine to monitor autonomic diseases correlated to atypical sympathetic activation. The Matlab code implementing the ComEDA algorithm is available online.

The salivary-α-amylase level after stroop test in anxious patients can predict the severity of anxiety

Individuals with anxiety disorder often exhibit as imbalance in response to stressors. We sought to explore the relationship between physiological as well as psychological responses under acute mental stress and the severity of the disease. 20 Generalized Anxiety Disorder (GAD) patients (14 males, mean age 46 ± 10 years) were confronted with the stroop test, during which salivary-α-amylase (sAA), salivary cortisol, and heart rate variability (HRV) were assessed. The results showed that stroop test as a stressor induced autonomic nervous response in GAD patients, which was mainly manifested as the increase in HRV representing sympathetic nervous system and the decrease in HRV representing vagal nerve activity. Moreover, the basic function of sympathetic-adrenal medulla system was hyperfunctional in GAD patients while theirs reactivity was limited, which showed the more serious the lesion was, the higher the baseline value of sAA was, and the less sAA secretion increase would be, or even decrease after mental stress. The change of sAA after stroop test in GAD patients can predict the severity of anxiety, but subjective psychological perception can not.

High-Frequency Heart Rate Variability Reactivity and Trait Worry Interact to Predict the Development of Sleep Disturbances in Response to a Naturalistic Stressor

BACKGROUND

High-frequency heart rate variability (HF-HRV) reactivity was proposed as a vulnerability factor for stress-induced sleep disturbances. Its effect may be amplified among individuals with high trait worry or sleep reactivity.

PURPOSE

This study evaluated whether HF-HRV reactivity to a worry induction, sleep reactivity, and trait worry predict increases in sleep disturbances in response to academic stress, a naturalistic stressor.

METHOD

A longitudinal study following 102 undergraduate students during an academic semester with well-defined periods of lower and higher academic stress was conducted. HF-HRV reactivity to a worry induction, trait worry using the Penn State Worry Questionnaire, and sleep reactivity using the Ford Insomnia Stress Reactivity Test were measured during the low stress period. Sleep disturbances using the Pittsburgh Sleep Quality Index were assessed twice during the lower stress period and three times during the higher stress period.

RESULTS

Greater reductions in HF-HRV in response to the worry induction predicted increases in sleep disturbances from the lower to the higher academic stress period. Trait worry moderated this association: individuals with both higher trait worry and greater HF-HRV reactivity to worry had larger increases in stress-related sleep disturbances over time, compared to participants with lower trait worry and HF-HRV reactivity. A similar, but marginally significant effect was found for sleep reactivity.

CONCLUSION

This study supports the role of HF-HRV reactivity as a vulnerability factor for stress-induced sleep disturbances. The combination of high trait worry and high HF-HRV reactivity to worry might identify a subgroup of individuals most vulnerable to stress-related sleep disturbances.

Emotion regulation strategies in trauma-related disorders: pathways linking neurobiology and clinical manifestations

Emotion regulation impairments with traumatic origins have mainly been studied from posttraumatic stress disorder (PTSD) models by studying cases of adult onset and single-incident trauma exposure. The effects of adverse traumatic experiences, however, go beyond the PTSD. Different authors have proposed that PTSD, borderline personality, dissociative, conversive and somatoform disorders constitute a full spectrum of trauma-related conditions. Therefore, a comprehensive review of the neurobiological findings covering this posttraumatic spectrum is needed in order to develop an all-encompassing model for trauma-related disorders with emotion regulation at its center. The present review has sought to link neurobiology findings concerning cortico-limbic function to the field of emotion regulation. In so doing, trauma-related disorders have been placed in a continuum between under- and over-regulation of affect strategies. Under-regulation of affect was predominant in borderline personality disorder, PTSD with re-experiencing symptoms and positive psychoform and somatoform dissociative symptoms. Over-regulation of affect was more prevalent in somatoform disorders and pathologies characterized by negative psychoform and somatoform symptoms. Throughout this continuum, different combinations between under- and over-regulation of affect strategies were also found.

Emotion regulation, internalizing symptoms and somatic complaints in pediatric survivors of acute lymphoblastic leukemia

OBJECTIVES

This study aimed to examine whether respiratory sinus arrhythmia (RSA)-a physiological index of children's emotion regulation-moderates the relation between cancer diagnosis and internalizing problems in children.

METHODS

Participants were twenty-two 7-12-year survivors of acute lymphoblastic leukemia and 20 age-matched controls. RSA was calculated from cardiac interbeat interval using spectral time-series analysis. t-Scores on the Child Behavior Checklist Anxious/Depressed, Withdrawn/Depressed, and Somatic Complaints subscales were computed.

RESULTS

Respiratory sinus arrhythmia moderated the relation between diagnostic status and both child somatic complaints and withdrawn/depressed symptoms. The positive association between diagnostic status and somatic complaints was significant for children with low RSA but not significant for children with high RSA. This association was also significant for withdrawn/depressed symptoms. Low RSA was associated with more somatic complaints and withdrawn/depressed symptoms for children with cancer but not for control participants.

CONCLUSIONS

Children who have poor emotion regulation abilities may be more vulnerable to the range of stressors associated with the diagnosis, treatment, and survivorship of cancer. Behavioral interventions targeting emotion regulation skills may reduce internalizing symptoms in this population.

Gum chewing modulates heart rate variability under noise stress

OBJECTIVE

Gum chewing may relieve stress, although this hypothesis has not been proven. Heart-rate variability (HRV) is commonly used to measure stress levels. However, it is not known if gum chewing modulates HRV under acute stress. The aim of this study was to investigate the effects of gum chewing on HRV under acute stress.

MATERIALS AND METHODS

A cross-over study involving 47 non-smoking healthy subjects, aged 22-27 years, was carried out. The subjects received a stress procedure with gum chewing (GS group) and without gum chewing (S group). Additionally, the other 20 subjects were allocated to the gum chewing without stress group (G group). The GS and S groups were exposed to noise for 5 min (75 dBA) as stress. Before and after stress exposure/gum chewing, participants completed the state portion of the State-Trait Anxiety Inventory (STAI-s) and a single Stress Visual Analogue Scale (VAS) measurement. HRV measurement was performed before and during stress/gum chewing for 5 min.

RESULTS

After the stress procedure, VAS score significantly increased in the GS and S groups. During the stress procedure, the GS group showed a significantly lower level of high frequency (HF) and higher levels of low frequency (LF) and LF/HF than the S group. However, there were no significant differences in the scores of the state portion of the State-Trait Anxiety Inventory (STAI-s) and VAS between the two stress groups.

CONCLUSIONS

These findings suggest that gum chewing modulates HRV, but may not relieve acute stress caused by noise.

Cognitive and physiological dissociations in response to emotional pictures in patients with anorexia

Recent studies suggest that patients with anorexia may express dissociated cognitive and physiological reactivities to emotional stimuli. The present research aimed to compare subjective and autonomic responses to pleasant, unpleasant and neutral scenes during a categorization task and an activation rating task in anorexic (AN), alexithymic (AL), depressed (DEP) and control participants (CONT). The participants first categorized pictures according to their emotional valence, followed by a rating of their activation level, concomitant with the recording of skin conductance responses (SCRs). Main findings showed that the AN patients presented major difficulty in categorizing pictures, particularly neutral ones. Contrary to the AL participants, this difficulty did not induce significant increases of SCR amplitude in the AN patients. In the second task, the AN patients rated the intensity of activation of unpleasant pictures higher than the AL participants and that of pleasant ones higher than the AL and CONT participants. In addition, no significant linear correlation was observed between the intensity of activation ratings and SCR amplitude in the AN, AL or DEP participants contrarily to what was observed for control participants. This lack of relation suggests a non-specific disconnection between physiological and cognitive self-reported responses to emotional stimuli. Our results highlight a specific form of emotional processing in the AN patients distinct from that observed in alexithymia or depression and characterized by a dissociation between cognitive and physiological responses. This kind of disconnection could be associated with emotional regulation processes and may benefit the AN patients by lowering the psychological stress response.

Process and outcome evaluation of vocational rehabilitation interventions in patients with prolonged fatigue complaints

BACKGROUND

Prolonged fatigue can cause physical, mental and occupational disability. Fatigue often persists because of a combination of biopsychosocial factors.

PURPOSE

To evaluate the process and outcomes of three existing outpatient vocational rehabilitation interventions (VRI) in patients with prolonged fatigue complaints. The VRIs differ with regard to the content and treatment duration, enrolment procedure and financing.

METHOD

A pre-post design was used with repeated measurements before treatment, after treatment and 3 months after treatment. Primary outcomes (fatigue and work participation) and secondary outcomes (physical and social functioning, mental health and physiological indicators (heart rate variability)) were assessed over time using linear mixed models analysis. A process evaluation (i.e. patient reach, content completeness and patient satisfaction) was conducted as well.

RESULTS

One hundred patients participated. Post-treatment, fatigue decreased (p < .001) and work participation (p < .010), physical functioning (p < .001) and mental health (p < .001) improved considerably in all three VRIs. Social functioning improved in one VRI (p = .022), but did not in the other two (p = .442, p = .196, respectively). Physiologically, heart rate variability improved in two VRIs (p = .044, p = .038, respectively). VRIs were administered according to the programme protocol. Almost all patients met their personal goals and the majority was satisfied with the outcomes of diminished constraints at work.

CONCLUSION

Three VRIs showed significant and clinically relevant outcomes over time regarding decreased fatigue and improved functioning and work participation in fatigued patients. The VRIs administered patient-tailored biopsychosocial interventions as planned and patients were satisfied with the interventions.

Evaluation of the effects of a training programme for patients with prolonged fatigue on physiological parameters and fatigue complaints

OBJECTIVES

Complaints of prolonged fatigue are considered as a major health problem, as it can affect daily functioning and may lead to work disability. To increase knowledge about the effectiveness of interventions focussing on fatigued patients, a study was designed to evaluate an established training programme for patients with prolonged fatigue.

MATERIALS AND METHODS

Eighteen patients who reported fatigue to be one of their major health complaints and who were suffering from functional impairments attended a training programme of six weeks, three times a week. The training consisted mainly of physical endurance training, relaxation therapy and breathing exercises in rest. At baseline, time- and frequency-domain measures of heart rate variability (HRV) and respiration rate measurements were recorded during rest and during recovery after bicycle exercise. Furthermore, fatigue complaints were assessed with the Checklist Individual Strength (CIS). These measurements were repeated at three weeks and six weeks from baseline.

RESULTS

After three weeks, HRV increased significantly in rest--SDNN, i.e. standard deviation of normal beat-to-beat intervals (p = 0.02), very low frequency (p = 0.04) and low frequency (p = 0.04)--and showed a positive trend in the remaining HRV components. No significant HRV changes during recovery were found. Respiration rate decreased significantly after six weeks during rest (from 11.8, SD = 4.65 to 8.1, SD = 2.57 b x min-1) and during recovery (from 15.1, SD = 4.90 to 10.4, SD = 2.97 b x min-1). In all patients, CIS scores decreased after six weeks training (from 106, SD = 13.3 to 78, SD = 21.8, p = 0.001).

CONCLUSIONS

The results suggest that a six-week training programme has a beneficial effect on physiological and subjective parameters in patients with severe complaints of fatigue.

Altered coordination of the neuroendocrine response during psychosocial stress in subjects with high trait anxiety

Contradicting data are available on stress responsiveness in subjects with high anxiety. In the present study we tested the hypothesis that high trait anxiety is associated with impaired coordination of the stress response, rather than global hypo- or hyper-responsiveness. The sample consisted of subjects with high (n=15) and with low (n=12) trait anxiety. Subjects with middle-range levels of anxiety were excluded from the study. After psychological characterization, the volunteers were exposed to a public speech procedure. A spectrum of neuroendocrine parameters was measured before, during and after the procedure and the results were analyzed by exploratory statistics. Psychological characterization of subjects revealed a lower preference for task-oriented but a higher one for emotion-oriented coping strategies as well as lower scores on hardiness in subjects with high trait anxiety. After the speech procedure, differences in selected mood and personality characteristics were observed, with the anxious group scoring significantly higher in scales for stress, tiredness, arousal, anxiety and depression. Factor analysis revealed that one common factor grouped blood pressure, catecholamine concentrations in blood and heart rate in non-anxious subjects, while three distinct factors separated these parameters in anxious subjects. Correlation analysis in anxious subjects showed that lower adrenocorticotropin (ACTH) and cortisol responses during stress were associated with exaggerated perception of stress and worse mental performance. Our findings indicate that subjects with high anxiety have different relationships between specific neuroendocrine parameters, subjective perception of stress and Stroop test performance.

Verbal-autonomic response dissociations as traits?

Dissociations between subjective and physiological responses to stress are of central interest in coping research. However, little is known about their stability across situations and time. Two experimental sessions - separated by 1 year - were conducted to examine cross-situational consistency and longterm-stability of HR-derived and SCL-derived dissociation scores. In year 1, a speech stressor, the cold pressor and a video stressor (viewing of the speech video) were applied. In year 2, mental arithmetics, anagrams and a torture video were presented. Thirty-five students participated and HR, SCL and negative affect were recorded. For each stressor, standardized changes in negative affect were subtracted from changes in autonomic reactivity (HR and SCL, respectively). Dissociation scores were relatively consistent across the stressors with HR-derived scores exceeding SCL-derived scores. Longterm-stability proved acceptable (r=.61, P<.001 for HR-derived and r=.40, P<.05 for SCL-derived scores). In sum, verbal-autonomic response dissociations show considerable cross-situational and temporal stability and thus might be considered as traits.

Manipulation of frontal brain asymmetry by cognitive tasks

The purpose of the present study was to evaluate whether verbal fluency tasks may specifically induce relatively greater left than right hemispheric activation in the dorsolateral prefrontal cortex. The effectiveness of the manipulation was evaluated by EEG, which was recorded during performance of the verbal fluency task and during two control conditions, i.e., a baseline condition without cognitive demands, and a mental arithmetic task, respectively. The results demonstrate that the desired effect can only be achieved in individuals with good performance on the verbal fluency task. Good and poor performers do not only differ in lateral asymmetry, but also in the most affected region within the prefrontal cortex. Whereas good performers show relatively increased activation in the cortical region and hemisphere putatively most specialized for this kind of task (i.e., the left dorsolateral frontal cortex), poor performers show a marked shift of frontopolar asymmetry to the right.