Personality and electrodermal response lability: an interpretation

Autonomic reactivity during acute social stress: exploratory investigation of an interaction by threat interpretation bias and emotion regulation difficulties

Objective: This preliminary study examined the interactive influences of interpretation bias and emotion dysregulation in predicting autonomic stress response.Methods: Participants (N = 72 college students; ages 18-25, 70% female, 47% Hispanic/Latinx), completed a performance-based assessment of threat interpretation bias and self-report measures of emotion regulation difficulties. Electrodermal activity (EDA; skin conductance level) was collected while participants completed a standardized psychosocial stressor task.Results: Interpretation bias and emotion regulation difficulties interacted to predict EDA trajectories (β = 0.054, SE = .001, CI:.007, .002, p < .001) during acute stress: presence of either interpretation bias toward threat (β = 6.950, SE = 2.826, CI: 1.407, 12.488, p = .013) or emotion regulation difficulties (β = 9.387, SE = 3.685, CI: 2.141, 16.636, p = .011) was associated with greater reactivity and poorer recovery; presence of both was associated with the lowest resting state EDA and blunted reactivity (β = 1.340, SE = 3.085, CI: -4.721, 7.407, p = .66).Conclusions: Preliminary findings support interpretation bias and emotion regulation difficulties, and their distinct interactive patterns, as predictors of autonomic reactivity trajectories during stress. Interpretation bias modification and emotion regulation skills may be important intervention targets for common psychological conditions that are influenced by aberrant psychophysiological processes.

Adaptive thresholding increases sensitivity to detect changes in the rate of skin conductance responses to psychologically arousing stimuli in both laboratory and ambulatory settings

Psychophysiologists recording electrodermal activity (EDA) often derive measures of slow, tonic activity-skin conductance level (SCL)-and faster, more punctate changes-skin conductance responses (SCRs). A SCR is conventionally considered to have occurred when the local amplitude of the EDA signal exceeds a researcher-determined threshold (e.g., 0.05 μS), typically fixed across study participants and conditions. However, fixed SCR thresholds can preferentially exclude data from individuals with low SCL because their SCRs are smaller on average, thereby reducing statistical power for group-level analyses. Thus, we developed a fixed plus adaptive (FA) thresholding method that adjusts identification of SCRs based on an individual's SC at the onset of the SCR to increase statistical power and include data from more participants. We assess the utility of applying FA thresholding across two independent samples and explore age and race-related associations with EDA outcomes. Study 1 uses wired EDA measurements from 254 healthy adults responding to evocative images and sounds in a laboratory setting. Study 2 uses wireless EDA measurements from 20 children with autism in a clinical environment while they completed behavioral tasks. Compared to a 0.01, 0.03, and 0.05 μS fixed threshold, FA thresholding at 1.9% modestly increases statistical power to detect a difference in SCR rate between tasks with higher vs. lower subjective arousal and reduces exclusion of participants by up to 5% across both samples. This novel method expands the EDA analytical toolbox and may be useful in populations with highly variable basal SCL or when comparing groups with different basal SCL. Future research should test for reproducibility and generalizability in other tasks, samples, and contexts. IMPACT STATEMENTS: This article is important because it introduces a novel method to enhance sensitivity and statistical power in analyses of skin conductance responses from electrodermal data.

Digital Phenotyping for Differential Diagnosis of Major Depressive Episode: Narrative Review

BACKGROUND

Major depressive episode (MDE) is a common clinical syndrome. It can be found in different pathologies such as major depressive disorder (MDD), bipolar disorder (BD), posttraumatic stress disorder (PTSD), or even occur in the context of psychological trauma. However, only 1 syndrome is described in international classifications (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition [DSM-5]/International Classification of Diseases 11th Revision [ICD-11]), which do not take into account the underlying pathology at the origin of the MDE. Clinical interviews are currently the best source of information to obtain the etiological diagnosis of MDE. Nevertheless, it does not allow an early diagnosis and there are no objective measures of extracted clinical information. To remedy this, the use of digital tools and their correlation with clinical symptomatology could be useful.

OBJECTIVE

We aimed to review the current application of digital tools for MDE diagnosis while highlighting shortcomings for further research. In addition, our work was focused on digital devices easy to use during clinical interview and mental health issues where depression is common.

METHODS

We conducted a narrative review of the use of digital tools during clinical interviews for MDE by searching papers published in PubMed/MEDLINE, Web of Science, and Google Scholar databases since February 2010. The search was conducted from June to September 2021. Potentially relevant papers were then compared against a checklist for relevance and reviewed independently for inclusion, with focus on 4 allocated topics of (1) automated voice analysis, behavior analysis by (2) video and physiological measures, (3) heart rate variability (HRV), and (4) electrodermal activity (EDA). For this purpose, we were interested in 4 frequently found clinical conditions in which MDE can occur: (1) MDD, (2) BD, (3) PTSD, and (4) psychological trauma.

RESULTS

A total of 74 relevant papers on the subject were qualitatively analyzed and the information was synthesized. Thus, a digital phenotype of MDE seems to emerge consisting of modifications in speech features (namely, temporal, prosodic, spectral, source, and formants) and in speech content, modifications in nonverbal behavior (head, hand, body and eyes movement, facial expressivity, and gaze), and a decrease in physiological measurements (HRV and EDA). We not only found similarities but also differences when MDE occurs in MDD, BD, PTSD, or psychological trauma. However, comparative studies were rare in BD or PTSD conditions, which does not allow us to identify clear and distinct digital phenotypes.

CONCLUSIONS

Our search identified markers from several modalities that hold promise for helping with a more objective diagnosis of MDE. To validate their potential, further longitudinal and prospective studies are needed.

Galvanic Skin Response Features in Psychiatry and Mental Disorders: A Narrative Review

This narrative review is aimed at presenting the galvanic skin response (GSR) Biofeedback method and possibilities for its application in persons with mental disorders as a modern form of neurorehabilitation. In the treatment of mental disorders of various backgrounds and courses, attention is focused on methods that would combine pharmacological treatment with therapies improving functioning. Currently, the focus is on neuronal mechanisms which, being physiological markers, offer opportunities for correction of existing deficits. One such indicator is electrodermal activity (EDA), providing information about emotions, cognitive processes, and behavior, and thus, about the function of various brain regions. Measurement of the galvanic skin response (GSR), both skin conductance level (SCL) and skin conductance responses (SCR), is used in diagnostics and treatment of mental disorders, and the training method itself, based on GSR Biofeedback, allows for modulation of the emotional state depending on needs occurring. Summary: It is relatively probable that neurorehabilitation based on GSR-BF is a method worth noticing, which-in the future-can represent an interesting area of rehabilitation supplementing a comprehensive treatment for people with mental disorders.

Electrodermal Activity Is Sensitive to Sleep Deprivation but Does Not Moderate the Effect of Total Sleep Deprivation on Affect

Emotion is characterized by dimensions of affective valence and arousal, either or both of which may be altered by sleep loss, thereby contributing to impaired regulatory functioning. Controlled laboratory studies of total sleep deprivation (TSD) generally show alterations in physiological arousal and affective state, but the relationship of affect and emotion with physiological arousal during TSD has not been well characterized. Established methods for examining physiological arousal include electrodermal activity (EDA) measures such as non-specific skin conductance responses (NSSCR) and skin conductance level (SCL). These measures are robust physiological markers of sympathetic arousal and have been linked to changes in experienced emotion. To explore the link between physiological arousal and affect during sleep deprivation, we investigated individuals’ EDA under TSD and its relationship to self-reported affect. We also investigated the relationship of EDA to two other measures known to be particularly sensitive to the arousal-decreasing effects of TSD, i.e., self-reported sleepiness and performance on a vigilant attention task. Data were drawn from three previously published laboratory experiments where participants were randomly assigned to either well-rested control (WRC) or 38 h of TSD. In this data set, comprising one of the largest samples ever used in an investigation of TSD and EDA (N = 193 with 74 WRC and 119 TSD), we found the expected impairing effects of TSD on self-reported affect and sleepiness and on vigilant attention. Furthermore, we found that NSSCR, but not SCL, were sensitive to TSD, with significant systematic inter-individual differences. Across individuals, the change in frequency of NSSCR during TSD was not predictive of the effect of TSD on affect, sleepiness, or vigilant attention, nor was it related to these outcomes during the rested baseline. Our findings indicate that while physiological arousal, as measured by EDA, may be useful for assessing TSD-related changes in non-specific arousal at the group level, it is not associated with individuals’ self-reported affect at rest nor their change in affect during TSD. This suggests that an essential aspect of the relationship between physiological arousal and self-reported affect is not well captured by EDA as measured by NSSCR.

Pre-pandemic electrodermal activity predicts current COVID-related fears: household size during lockdown as a moderating factor

Background: Despite the immense impact of COVID-19 on mental health, there is a lack of prospective studies examining physiological predictors of current risk factors. Moreover, although physiological processes evidently interact with socio-demographic factors to modulate individuals' response to a crisis, it remains largely unknown how these complex interactions shape people's mental responses to COVID-19. To fill these gaps of knowledge, we chose a potent physiological marker of distress - heightened baseline electrodermal activity (EDA) measured before the pandemic began - and hypothesized it would be related to greater COVID-related fears and worries as a function of individuals' household size.Method: 185 individuals (71% women), who had participated in our lab studies 2-3 years ago, in which we assessed their baseline EDA, completed several questionnaires online, including assessments of their current fears regarding COVID. Participants also reported the number of people in their household, with whom they had been together during a lockdown which was taking place at the time. We used pre-pandemic EDA measures in combination with their household size to predict participants' current fears.Results: Pre-pandemic EDA measures predicted current COVID-related fears and worries. Specifically for the EDA measure "number of skin conductance responses", we further found that the number of people in the household during the lockdown, moderated the abovementioned relationship, such that it occurred in individuals with average and larger households and not in those with small households.Conclusions: We provide a highly relevant and unique combination of physiological, socio-demographic, and psychological measures, which augments the potential to optimally target populations vulnerable to COVID-related distress, and subsequently offer them early mental health interventions.

Electrodermal activity for measuring cognitive and emotional stress level

Stress can lead to harmful conditions in the body, such as anxiety disorders and depression. One of the promising noninvasive methods, which has been widely used in detecting stress and emotion, is electrodermal activity (EDA). EDA has a tonic and phasic component called skin conductance level and skin conductance response (SCR). However, the components of the EDA cannot be directly extracted and need to be deconvolved to obtain it. The EDA signals were collected from 18 healthy subjects that underwent three sessions – Stroop test with increasing stress levels. The EDA signals were then deconvoluted by using continuous deconvolution analysis (CDA) and convex optimization approach to electrodermal activity (cvxEDA). Four features from the result of the deconvolution process were collected, namely sample average, standard deviation, first absolute difference, and normalized first absolute difference. Those features were used as the input of the classification process using the extreme learning machine (ELM). The output of classification was the stress level; mild, moderate, and severe. The visual of the phasic component using cvxEDA is more precise or smoother than the CDA's result. However, both methods could separate SCR from the original skin conductivity raw and indicate the small peaks from the SCR. The classification process results showed that both CDA and cvxEDA methods with 50 hidden layers in ELM had a high accuracy in classifying the stress level, which was 95.56% and 94.45%, respectively. This study developed a stress level classification method using ELM and the statistical features of SCR. The result showed that EDA could classify the stress level with over 94% accuracy. This system could help people monitor their mental health during overworking, leading to anxiety and depression because of untreated stress.

Pre-pandemic autonomic nervous system activity predicts mood regulation expectancies during COVID-19 in Israel

Despite the unfolding impact of the COVID‐19 pandemic on psychological well‐being, there is a lack of prospective studies that target physiological markers of distress. There is a need to examine physiological predictors from the pre‐pandemic period to identify and treat individuals at‐risk. In this study, our aim was to use pre‐pandemic markers of autonomic nervous system (ANS) parasympathetic and sympathetic regulation to predict individuals' psychological well‐being during the crisis. We also assessed the role of mood regulation expectancies as a mediator of the association between pre‐pandemic physiological measures and COVID‐related well‐being. In May to June 2020, 185 Israeli adults completed online questionnaires assessing their mood regulation expectancies since COVID‐19 began, and their current well‐being. These individuals had participated in lab studies 1.5–3 years prior to this assessment, where their physiological measures were taken, including respiratory sinus arrhythmia (RSA) and skin conductance level (SCL). RSA was positively related to mood regulation expectancies during COVID‐19 (b = 3.46, 95% CI [0.84, 6.05]). Mood regulation expectancies, in turn, positively predicted well‐being during the crisis (b = 0.021, 95% CI [0.016, 0.027]). The mediation was significant and moderated by SCL (index = −0.09, 95% CI [−0.02, −0.0001]), such that it was strongest for individuals with low SCL. We point to pre‐pandemic physiological mechanisms underlying individuals' mental well‐being during the COVID‐19 pandemic. These findings have theoretical, diagnostic, and clinical implications that may refine our understanding of the physiological basis of resilience to the COVID‐19 pandemic and thus may be implemented to identify and assist individuals in these times.

Our study offers a unique psychophysiological approach to predicting mood regulation and mental well‐being during COVID‐19 from pre‐pandemic resting physiological activity. We show that pre‐pandemic markers of the autonomic nervous system, which were collected during routine 2–3 years prior to the pandemic, allow us to prospectively understand emotion regulation and well‐being during COVID‐19.

Conscientiousness in Pilots Correlates with Electrodermal Stability: Study on Simulated Flights under Social Stress

For pilots, the capacity to cope with anxiety is crucial during a flight since they may be confronted with stressful situations. According to the Big Five Inventory, this capacity can be modulated by two important personality traits: conscientiousness and neuroticism. The former would be related to concentration skills and the latter to the attention bias towards anxiety-provoking stimuli. Given the current development of monitoring systems for detecting the users’ state, which can be incorporated into cockpits, it is desirable to estimate their robustness to inter-individual personality differences. Indeed, several emotion recognition methods are based on physiological responses that can be modulated by specific personality profiles. The personality traits of twenty pilots were assessed. Afterwards, they performed two consecutive simulated flights without and with induced social stress while electrodermal activity was measured. Their subjective anxiety was assessed before the second flight, prior to the stress-induced condition. The results showed that higher scores in neuroticism correlated positively with cognitive and somatic anxiety. Moreover, under social stress, higher scores in conscientiousness correlated positively with electrodermal stability, i.e., a lower number of skin conductance responses. These results on both self-reported and physiological responses are in favor of the integration of personality differences into pilots’ state monitoring.

Initial Results of Tests Using GSR Biofeedback as a New Neurorehabilitation Technology Complementing Pharmacological Treatment of Patients with Schizophrenia

Galvanic skin response (GSR) Biofeedback uses training to reduce tension and anxiety and improve concentration and self-regulation. The study was aimed to evaluate this method as a form of rehabilitation and quantify the outcomes achieved by patients undergoing training using this technique. Six schizophrenic patients were enrolled in the study and underwent training based on the relaxation training module (CENTER), concentration training module (BALANCE), and self-regulation training module (INSECTS). Training sessions were held twice a week for 6 weeks. From the total group of subjects involved in the study, two patients had a statistically significant increase in measured values after the CENTER exercise, indicating that relaxation was achieved. Four patients showed a statistically significant decrease in measured values after the BALANCE exercise, which was reflective of an improvement in concentration. Three patients had a statistically significant decrease in measured values after the INSECTS exercise, which indicated an improvement in self-regulation. GSR Biofeedback may be used to complement the pharmacological treatment of patients diagnosed with schizophrenia.

Validation of Affect-tag Affective and Cognitive Indicators

The Affect-tag solution measures physiological signals to deliver indicators derived from cognitive science. To provide the most accurate and effective results, a database of electrodermal activity (EDA) signals acquired using the Affect-tag A1 band was created. An experimental paradigm was designed to measure action-taking, autonomic regulation, cognitive load (CL), emotions, and stress, affects, and social stress. The Affect-tag emotional power (EP), emotional density (ED), and CL affective and cognitive indicators were refined based on the physiological responses of 48 participants during these tasks. Statistical significance was obtained for all indicators in tasks they were designed to measure, resulting in a total accuracy score of 89% for the combined indicators. Data obtained during this study will be further analyzed to define emotional and affective states.

Reinforcement of Self-Regulated Brain Activity in Schizophrenia Patients Undergoing Rehabilitation

The experiment was aimed to compare the effects of different forms of rehabilitation applied in patients with schizophrenia. Verification of the obtained results was based on the analysis of the level of cognitive and social functioning of the subjects. For this purpose, the following clinical tools were used: Positive and Negative Syndrome Scale (PANSS), Beck Cognitive Insight Scale (BCIS), Color Trial Test (CTT-1, CTT-2), d2 psychological tests, Acceptance of Illness Scale (AIS), Self-efficacy Scale (GSES), Quantitative Electroencephalogram Biofeedback (QEEG-BF), auditory event-related potentials (ERPs), and serum levels of brain-derived neurotrophic factor (BDNF). The subjects were mentally stable male schizophrenia patients who had been in remission. They were divided into two groups which received different types of rehabilitation for three months. Group 1 patients followed a standard rehabilitation and Group 2 patients received GSR Biofeedback (galvanic skin response Biofeedback, GSR-BF) training. Pretherapy and posttherapy measurements were made for each group. Experimental rehabilitation based on GSR-BF training resulted in regulatory control of neurophysiological mechanisms, and the parameters obtained demonstrated improvement in the subjects' cognitive and social function. The following therapy outcomes were observed: (1) reduce psychopathological symptoms (2) improving cognitive (concentration, attention) and social functions (3) increase in the neurotrophic factor BDNF. GSR-BF can be used as an alternative to conventional rehabilitation in schizophrenia patients.

Integrating Biosignals Measurement in Virtual Reality Environments for Anxiety Detection

This paper proposes a protocol for the acquisition and processing of biophysical signals in virtual reality applications, particularly in phobia therapy experiments. This protocol aims to ensure that the measurement and processing phases are performed effectively, to obtain clean data that can be used to estimate the users' anxiety levels. The protocol has been designed after analyzing the experimental data of seven subjects who have been exposed to heights in a virtual reality environment. The subjects' level of anxiety has been estimated based on the real-time evaluation of a nonlinear function that has as parameters various features extracted from the biophysical signals. The highest classification accuracy was obtained using a combination of seven heart rate and electrodermal activity features in the time domain and frequency domain.

Neuromarketing Highlights in How Asperger Syndrome Youth Perceive Advertising

This study examines how advertising material and brands related to organizational communication are perceived by people with Asperger syndrome, a form of autism. The main objective of the study was to understand whether the perception of advertising differs between individuals with AS and a neurotypical population. Neuromarketing techniques were used to examine two key variables, attention and emotion, which were also measured by physiological and biometric variables. The results were compared with those of a control group from a neurotypical population; i.e., participants who had not been diagnosed with any type of developmental disorder. Commercial advertisements were the preferred material used in this research although social-themed advertisements were also included, some produced by commercial companies and others by institutional advertisers (NGOs and foundations). Qualitative techniques were also used to explain the observed phenomena. Data revealed significant differences between the two groups in their perception of advertising and organizational communication with respect to attention and emotion variables.

Neural correlates of non-specific skin conductance responses during resting state fMRI

Skin conductance responses (SCRs) reliably occur in the absence of external stimulation. However, the neural correlates of these non-specific SCRs have been less explored than brain activity associated with stimulus-elicited SCRs. This study modeled spontaneous skin conductance responses observed during an unstructured resting state fMRI scan in 58 adolescents. A Finite Impulse Response (FIR) fMRI model was used to detect any type of hemodynamic response shape time-locked to non-specific SCRs; the shape of these responses was then carefully characterized. The strongest evidence for signal change was found in several sub-regions of sensorimotor cortex. There also was evidence for engagement of discrete areas within the lateral surfaces of the parietal lobe, cingulate cortex, fronto-insular operculum, and both visual and auditory primary processing areas. The hemodynamic profile measured by FIR modeling clearly resembled an event-related response. However, it was a complex response, best explained by two quickly successive, but opposing neuronal impulses across all brain regions - a brief positive response that begins several seconds prior to the SCR with a much longer negative neuronal impulse beginning shortly after the SCR onset. Post hoc exploratory analyses linked these two hemodynamic response phases to different emotion-related individual differences. In conclusion, this study shows the neural correlates of non-specific SCRs are a widespread, cortical network of brain regions engaged in a complex, seemingly biphasic fashion. This bimodal response profile should be considered in replication studies that attempt to directly link brain activity to possible homeostatic mechanisms or seek evidence for alternative mechanisms.

Candidate Biomarkers of Suicide Crisis Syndrome: What to Test Next? A Concept Paper

BACKGROUND

There has been increasing interest in both suicide-specific diagnoses within the psychiatric nomenclature and related biomarkers. Because the Suicide Crisis Syndrome-an emotional crescendo of several interrelated symptoms-seems to be promising for the identification of individuals at risk of suicide, the aim of the present paper is to review the putative biological underpinnings of the Suicide Crisis Syndrome symptoms (entrapment, affective disturbance, loss of cognitive control, hyperarousal, social withdrawal).

METHODS

A PubMed literature search was performed to identify studies reporting a link between each of the 5 Suicide Crisis Syndrome symptoms and biomarkers previously reported to be associated with suicidal outcomes.

RESULTS

Disturbances in the hypothalamic-pituitary-adrenal axis, with dysregulated corticotropin-releasing hormone and cortisol levels, may be linked to a sense of entrapment. Affective disturbance is likely mediated by alterations in dopaminergic circuits involved in reward and antireward systems as well as endogenous opioids. Loss of cognitive control is linked to altered neurocognitive function in the areas of executive function, attention, and decision-making. Hyperarousal is linked to autonomic dysregulation, which may be characterized by a reduction in both heart rate variability and electrodermal activity. Social withdrawal has been associated with oxytocin availability. There is also evidence that inflammatory processes may contribute to individual Suicide Crisis Syndrome symptoms.

CONCLUSION

The Suicide Crisis Syndrome is a complex syndrome that is likely the consequence of distinct changes in interconnected neural, neuroendocrine, and autonomic systems. Available clinical and research data allow for development of empirically testable hypotheses and experimental paradigms to scrutinize the biological substrates of the Suicide Crisis Syndrome.

Obimon: An open-source device enabling group measurement of electrodermal activity

Electrodermal activity (EDA) provides the means to gauge the activity of the sympathetic nervous system. Assessment of EDA for research purposes requires measurement systems that are sensitive to small changes in arousal in the full measurement range, collecting, storing, and monitoring data. The objective behind designing a new open-source device was to be able to measure EDA simultaneously on many subjects, monitoring their activity in real time remotely and collecting high precision data suitable for analyses. To assure feasibility of simultaneous measurements on multiple subjects, the devices must be compact and wearable, without compromising data quality. Experiments were carried out using synchronized devices in group and single subject environments. Validity of EDA measurements of Obimon was demonstrated compared to a reference system (Nexus) during a breathing exercise, a short movie, and while exposed to loud computer-generated tones, using Pearson correlation, Passing-Bablok regression, and Bland-Altman analysis. Seamless management of several Obimons and real-time visualization of EDA via Android phone/tablet application from a large number of participants was demonstrated. Based on analyses of the data collected, we conclude that the Obimon device presented here is a valid and feasible tool for collecting EDA in single or multisubject environments.

Psychological Correlates of Nonspecific Electrodermal Responses

Spontaneous fluctuations in electrodermal responses are known as nonspecific electrodermal responses (NS.EDRs). The use of NS.EDRs as a tool in applied psychophysiological research has resulted in a variety of publications. NS.EDRs are examined separately as associated with the (as a biomarker of) levels of anxiety. The aim of this study was to compare changes (in terms of amplitude, frequency and time components) in NS.EDRs at two different (pre and post of an external stimulus) resting phases. NS.EDRs (nonspecific skin conductance responses (NS.SCRs), nonspecific skin potential responses (NS.SPRs), and nonspecific skin susceptance responses (NS.SSRs)) were recorded from 50 apparently healthy volunteers simultaneously at the same skin area. They were scored as NS.SCRs and NS.SSRs for changes greater than 0.02 μS and NS.SPRs greater than 0.02 mV. It was found that NS.EDRs, in particular NS.SCRs and NS.SPRs, were significantly changed in the second resting period, following the specific stimulus. More specifically, the amplitude of NS.EDRs were significantly decreased for NS.SCRs (p<0.001) and for NS.SPRs (p<0.005), but NS.SSRs remained stable. Moreover, the rise time of NS.SCRs was decreased in the second resting time. Furthermore, the frequency of responses was also changed. The computed NS.EDRs, in particular NS.SCRs and NS.SPRs could be of psychological interest and be used to study the electrodermal responses in detail. NS.SSRs were found to be robust with respect to nonspecific stimuli at various relaxation periods and their role was found to be less important in analysis of NS.EDRs in comparison to NS.SCRs and NS.SPRs at low frequency (20 Hz AC current). This should be considered in analysis of NS.EDRs. The computed NS.EDRs, especially NS.SCRs and NS.SPRs may be used as a useful measure of arousal due to their fast response and sensitivity to nonspecific stimuli and may also be used in assessment of individual differences.

Polyvictimization and Girls' Involvement in the Juvenile Justice System: Investigating Gender-Differentiated Patterns of Risk, Recidivism, and Resilience

A recent dramatic rise in girls' arrests has increased our need to examine whether our models of youth justice system involvement need to be differentiated by gender. Polyvictimization, in particular, has been implicated as a powerful predictor of youth problem behavior. However, recent research suggests that polyvictimization is associated with youth involvement in the justice system in ways that differ for girls at the levels of the independent variables (i.e., the sources of risk), the dependent variables (i.e., youth outcomes), and the mediators of these associations (i.e., the purported mechanisms that account for these relations). The present critique describes growth points in the current research with the goal of suggesting promising directions for future investigations. In particular, gaps are noted regarding our understanding of the specific forms of polyvictimization that affect traumatized girls' development, especially given the highly disproportionate prevalence of sexual abuse among justice-involved girls. In addition, increased attention is needed to gender differences in the timing of victimization and the onset of risky behavior, as well as the nature of trauma-linked youth offenses and recidivism, which research also suggests may differ for boys and girls. Furthermore, a new body of research on psychophysiological reactivity promises to shed light on gender differences in trauma response, resilience, and risk. Finally, the importance acknowledging the intersection of polyvictimization, gender, and race is noted. The article ends with a discussion of the ways in which understanding gender differences and similarities can inform gender-responsive approaches to prevention and intervention efforts.

The association between electrodermal activity (EDA), depression and suicidal behaviour: A systematic review and narrative synthesis

BACKGROUND

Electrodermal activity (EDA) and other peripheral autonomic electrical parameters have been used as indicators of emotional states, including depressive states and suicidal state. We aimed to review EDA research systematically, focusing on EDA's usefulness as a biomarker for depression and suicidal behaviour.

METHODS

We searched MEDLINE, Scopus, Cochrane Library, and Web of Science databases, following PRISMA guidelines. The initial screening of articles was based on titles and abstracts; then the full text was reviewed. A preliminary synthesis of findings was developed using tables, thematic analysis and quality ratings.

RESULTS

1287 articles were screened and 77 relevant studies were identified and included in the systematic review. The studies were fairly consistent in maintaining that hypoactive electrodermal response is an established feature of patients affected by depression. There is also preliminary evidence that monitoring EDA may help to differentiate the phases of mood disorders. A few studies provided evidence that EDA can be used to differentiate acutely suicidal subjects from depressed patients who are not severely suicidal. Although EDA has been shown to be a valid, sensitive marker of suicidal ideation, suicide attempts and violent suicidal behaviour, it also seems to be influenced to some extent by antidepressant treatment.

CONCLUSIONS

Most of the studies summarised in this review are quite outdated and employed a variety of designs and methods to evaluate EDA. This limits the generalisability of the results and makes it difficult to draw clear conclusions about the role of EDA in real-world settings. Electrodermal hypoactivity seems to be a reliable feature of depression and a valid marker of suicidal risk. Nevertheless, the potential utility of EDA in diagnosis, prevention, and treatment planning for depression and suicidal behaviour, should be thoroughly studied.

Visuospatial Working Memory Capacity Predicts Physiological Arousal in a Narrative Task

Physiological arousal that occurs during narrative production is thought to reflect emotional processing and cognitive effort (Bar-Haim et al. in Dev Psychobiol 44:238-249, 2004). The purpose of this study was to determine whether individual differences in visuospatial working memory and/or verbal working memory capacity predict physiological arousal in a narrative task. Visuospatial working memory was a significant predictor of skin conductance level (SCL); verbal working memory was not. When visuospatial working memory interference was imposed, visuospatial working memory was no longer a significant predictor of SCL. Visuospatial interference also resulted in a significant reduction in SCL. Furthermore, listener ratings of narrative quality were contingent upon the visuospatial working memory resources of the narrator. Potential implications for educators and clinical practitioners are discussed.

Depersonalization disorder: disconnection of cognitive evaluation from autonomic responses to emotional stimuli

BACKGROUND

Patients with depersonalization disorder (DPD) typically complain about emotional detachment. Previous studies found reduced autonomic responsiveness to emotional stimuli for DPD patients as compared to patients with anxiety disorders. We aimed to investigate autonomic responsiveness to emotional auditory stimuli of DPD patients as compared to patient controls. Furthermore, we examined the modulatory effect of mindful breathing on these responses as well as on depersonalization intensity.

METHODS

22 DPD patients and 15 patient controls balanced for severity of depression and anxiety, age, sex and education, were compared regarding 1) electrodermal and heart rate data during a resting period, and 2) autonomic responses and cognitive appraisal of standardized acoustic affective stimuli in two conditions (normal listening and mindful breathing).

RESULTS

DPD patients rated the emotional sounds as significantly more neutral as compared to patient controls and standardized norm ratings. At the same time, however, they responded more strongly to acoustic emotional stimuli and their electrodermal response pattern was more modulated by valence and arousal as compared to patient controls. Mindful breathing reduced severity of depersonalization in DPD patients and increased the arousal modulation of electrodermal responses in the whole sample. Finally, DPD patients showed an increased electrodermal lability in the rest period as compared to patient controls.

CONCLUSIONS

These findings demonstrated that the cognitive evaluation of emotional sounds in DPD patients is disconnected from their autonomic responses to those emotional stimuli. The increased electrodermal lability in DPD may reflect increased introversion and cognitive control of emotional impulses. The findings have important psychotherapeutic implications.

Characterizing electrodermal response habituation: a latent class approach with application to psychopathology

Response habituation is a fundamental form of nonassociative learning, yet there are substantial individual differences in its electrodermal manifestation. We employed a latent class analysis to identify discrete groups of electrodermal responders to a series of loud tones. We also evaluated whether heterogeneity in responsiveness was associated with lifetime prevalence of externalizing psychopathology and major depression. Participants were community-recruited men (N = 1,141) who underwent a standard habituation paradigm. A latent class analysis resulted in the identification of four electrodermal populations: rapid habituators, habituators, and two classes that showed weak response habituation, but differed markedly in their amplitude profiles. Relative to rapid habituators, members of slower habituating classes were less likely to receive lifetime diagnoses of antisocial personality disorder and substance dependence. Further research using this analytical strategy could help identify the functional significance of individual differences in habituation.

Dimensional assessment of psychopathy and its relationship with physiological responses to empathic images in juvenile offenders

OBJECTIVE

Many psychophysiological studies investigate whether psychopaths present low levels of electrodermal activity (EDA). However, despite evidence that varying degrees of psychopathy are normally distributed in the population, there is a paucity of EDA studies evaluating dimensionally. Moreover, although lack of empathy is a cornerstone of psychopathy, there has been a lack of studies using pictures of empathic emotional content to assess psychophysiological responses.

METHOD

We studied a population of young male delinquents (n = 30) from a detention center, using the Psychopathy Checklist Revised (PCL-R) to determine if higher levels of psychopathy were related to lesser degrees of EDA in response to emotion-eliciting pictures of empathic content.

RESULTS

There were significant correlations (p < 0.05) between latency and peak of EDA responses to unpleasant pictures and factor 1 scores, as well as between lability of EDA responses and factor 2 scores.

CONCLUSION

These results extend previous findings indicating direct relationship between EDA and psychopathy, and suggest that separate investigations of the two PCL-R factors have the potential to unravel more complex relationships between EDA and psychopathy. Also, by demonstrating such associations using emotion-provoking stimuli with empathic content, our results provide a link between levels of psychopathy and biological indices of empathic detachment.

Publication recommendations for electrodermal measurements

This committee was appointed by the SPR Board to provide recommendations for publishing data on electrodermal activity (EDA). They are intended to be a stand-alone source for newcomers and experienced users. A short outline of principles for electrodermal measurement is given, and recommendations from an earlier report (Fowles et al., ) are incorporated. Three fundamental techniques of EDA recording are described: (1) endosomatic recording without the application of an external current, (2) exosomatic recording with direct current (the most widely applied methodology), and (3) exosomatic recording with alternating current-to date infrequently used but a promising future methodology. In addition to EDA recording in laboratories, ambulatory recording has become an emerging technique. Specific problems that come with this recording of EDA in the field are discussed, as are those emerging from recording EDA within a magnetic field (e.g., fMRI). Recommendations for the details that should be mentioned in publications of EDA methods and results are provided.

Examining electrodermal hyporeactivity as a marker of externalizing psychopathology: a twin study

Literature suggests that reduced electrodermal reactivity (EDR) is related to externalizing problems. However, the genetic and environmental etiology of this association is unknown. Using a standard habituation paradigm, we measured responses to 15 loud tones in four cohorts of adolescent twins (N = 2,129). We quantified EDR as the average size of elicited responses (amplitude) and by counting the number of skin conductance responses (frequency). Externalizing liability was indexed through a general factor underlying substance-related problems and antisocial behavior. Response frequency, but not mean amplitude, was inversely associated with externalizing liability in each twin cohort. Biometric modeling revealed that most of the overlap between response frequency and externalizing liability was due to genetic influences common to both phenotypes. It is argued that neurological mechanisms involved in habituation may shed light on the etiology of psychopathology.

Increased executive functioning, attention, and cortical thickness in white-collar criminals

Very little is known on white-collar crime and how it differs to other forms of offending. This study tests the hypothesis that white-collar criminals have better executive functioning, enhanced information processing, and structural brain superiorities compared with offender controls. Using a case-control design, executive functioning, orienting, and cortical thickness was assessed in 21 white-collar criminals matched with 21 controls on age, gender, ethnicity, and general level of criminal offending. White-collar criminals had significantly better executive functioning, increased electrodermal orienting, increased arousal, and increased cortical gray matter thickness in the ventromedial prefrontal cortex, inferior frontal gyrus, somatosensory cortex, and the temporal-parietal junction compared with controls. Results, while initial, constitute the first findings on neurobiological characteristics of white-collar criminals. It is hypothesized that white-collar criminals have information-processing and brain superiorities that give them an advantage in perpetrating criminal offenses in occupational settings.

[The measurement of electrodermal activity]

INTRODUCTION

Electrodermal activity (EDA) is an early physiological index and the subject of constant interest, in spite of the bad reputation attached to "lie detectors". This interest is expected to increase in the future, following the development of research related to the neurobiological aspect of emotions of which it is an index. Recent data provided by functional cerebral imaging has added to the significance of this index and should result in further interest.

AIM

The authors thus re-examined the various notions related to measuring EDA, and its practical aspect as well as its mechanisms. EDA should be useful both for authors wishing to use this variable and for readers wishing to form their own critical point of view.

LITERATURE FINDINGS

The article first defines the various terms used to qualify EDA. Then, it analyses the mechanisms occurring at the sweat glands' level, showing that a distinct innervation of the sweat glands causes sweat to be released in the excretory channels, thereby allowing the recording of a negative surface potential in parallel to the lowering of skin conductance. Arguments are then pointed out to illustrate that the potential's positive phase following this first answer occurs in the case of high intensity stimulations. The study of the central command of sudation demonstrates that, several areas are involved and that different functions such as thermal regulation and motricity may interfere with emotive reactions. Difficulties regarding the mode of measurement of these answers as to their number and amplitude are also brought to light.

DISCUSSION

A particular interest of measuring EDA is its ability to highlight individual characteristic and unconscious emotional reactivity. Subjects who constitutionally present many spontaneous and therefore habitual EDA can indeed be opposed to subjects whose EDA reflexes are very few and hardly habitual. A theory suggests that for the first category, whose subjects are named labiles, emotional control may be at the origin of EDA. This characteristic brings to mind the case of antisocial subjects whose rate of EDA is also reduced, although for the latter a primitive drop in behavioral inhibition is involved. The production of EDA in response to non-conscious emotive stimulations can be objectified in the rare cases of prosopagnosia. These subjects who are unable to recognize familiar faces can produce EDA when presented faces with an emotional load. These cases contrast with the delusional denial of the Capgras syndrome where subjects do not present EDA, suggesting that the dysfunction of visual analysis occurs at a different level. There are other rare cases represented by cortical blindness where EDA shows that an unconscious emotional analysis is preserved. These subjects are known however to be capable of unconscious visual discriminations, which are possibly accompanied by EDA. This possibility of a "blind vision" is experimentally studied via subliminal vision testing (backward masking tests). These demonstrate that a rudimentary visual analysis is carried out in the subcortical circuits while taking into account the affective aspect of stimulations.

CONCLUSION

Present or future data should allow a greater comprehension of electrodermal signals, making it possible to overcome the difficulties related to their interpretation and facilitate their applications.

Galvanic skin resistance--a marker for endothelial damage in diabetes

BACKGROUND

Aging and diabetes are both associated with impaired vascular endothelial function. This causes a reduction in the resting blood flow and the blood flow response to autonomic stressors. Further, skin moisture and the ability to sweat are also reduced with aging and diabetes. The present investigation was undertaken to determine if the extent of damage from aging and diabetes could be accurately assessed by simply examining the electrodermal skin response (galvanic skin resistance) to a thermal stress.

STUDY DESIGN

Forty-five subjects whose average age was 31.2 +/- 8.3 years (younger group), 62.4 +/- 9.6 years (older group), and 61.8 +/- 11.3 years (diabetes group) were divided into three groups of 15 subjects. Subjects were exposed to environmental temperatures of 15 degrees C, 23 degrees C, or 32 degrees C for 30 min. During this period of time, sweat rate, skin blood flow, the electrodermal skin response, and skin moisture were measured.

RESULTS

There were significant impairments in skin moisture, sweat, skin blood flow, and the galvanic skin response at any of the three environmental temperatures in subjects with diabetes compared to older subjects compared to younger subjects (analysis of variance, P < 0.01). Both a reduction in skin blood flow and impaired sweating contributed to the higher galvanic skin resistance seen in subjects with diabetes. The greatest contributor was impaired sweating.

CONCLUSIONS

The results show that galvanic skin resistance, at any environmental temperature, may be a good means of assessing vascular damage and impaired sweat response in people with diabetes.