Electrodermal Measures Research Articles

Effects of imposed monitoring and blunting strategies on emotional reactivity

Abstract The present study examined the effects of imposed monitoring and blunting coping strategies on emotional reactivity in 40 subjects who prepared themselves for upcoming neutral and aversive slides. Besides subjective indices, electrodermal measures and eye blink startle responses were used to evaluate the effect of preparatory strategies. In order to investigate whether effects of strategies are modulated by individual differences in coping style, habitual monitoring was assessed with the Miller Behavioral Style Scale (MBSS; Miller, 1987). It was found that monitoring instructions resulted in higher levels of subjective anxiety during the anticipation of aversive slides than blunting instructions. In addition, when confronted with the frightening and neutral stimuli, monitoring instruction subjects showed smaller electrodermal reactivity than blunting instruction subjects. These effects were not found to be modulated by habitual coping style. Overall, the startle measure yielded no meaningful effects. Taken together, the results seem to indicate that emotional reactivity under threatening conditions is more affected by imposed coping strategies than by habitual coping styles as indexed by the MBSS.

Autonomic abnormalities in schizophrenia. State or trait indicators?

Tonic electrodermal measures have been widely used to index autonomic abnormalities in schizophrenia, whereas phasic electrodermal nonresponsiveness has been frequently used to index attentional orienting abnormalities. The primary objective of the present study was to assess whether these electrodermal abnormalities are episode indicators or vulnerability indicators. Twenty patients with a recent first episode of schizophrenia were tested during symptomatically remitted states and psychotic states. Twenty demographically matched normal controls were tested at two comparable intervals. Testing for stability of abnormalities across remitted and psychotic states allowed us to determine whether tonic and phasic electrodermal measures qualify as episode indicators or vulnerability indicators. Tonic electrodermal activity was abnormally elevated only during the psychotic state, which indicates that it is an episode indicator in schizophrenia. Phasic hyporesponsiveness relative to levels of general activation was present in both the remitted and the psychotic states, most strikingly during the psychotic state, and the proportion of patients who were electrodermally nonresponsive tended to be abnormally high during the remission test. Tonic electrodermal hyperarousal appears to be a state-sensitive episode indicator, whereas phasic electrodermal hyporesponsiveness to innocuous stimuli relative to activation level appears to be a mediating vulnerability factor.

Tonic and phasic electrodermal measures of human aversive conditioning with long duration stimuli.

Two experiments investigated phasic and tonic electrodermal responding to long, variable-duration stimuli in aversive conditioning procedures. Experiment I demonstrated reliable differential conditioning on both phasic (first interval response, FIR) and tonic (change in skin conductance level, delta SCL; spontaneous fluctuations) measures, using 10-40-s slides as conditioned stimuli (CSs) and electric shock as the unconditioned stimulus (UCS). Experiment 2 examined the sensitivity of phasic and tonic measures to UCS aversiveness. Both FIR and delta SCL were greater to a conditioned stimulus paired with shock than one paired with an innocuous reaction-time warning tone. Responding was reversed when the reinforcement contingencies were reversed. It was suggested that, with long duration CSs and an aversive UCS, phasic measures to stimulus onset, such as FIR, may reflect both stimulus significance and threat appraisal, whereas tonic measures reflect primarily arousal or anxiety arising from anticipation of the aversive unconditioned stimulus.

Imipramine and alprazolam effects on stress test reactivity in panic disorder

The reactivity of 40 panic disorder patients on mental arithmetic, cold pressor, and 5% CO 2 inhalation stressors was tested before and after 8 weeks of treatment with imipramine, alprazolam, or placebo. Mean levels of subjective and physiological stress measures were compared during a baseline before any stressors were given, and at anticipation, stressor, and recovery periods for each stressor. After treatment, imipramine patients differed from the other two treatment groups on the prestressor baseline in showing higher systolic blood pressure (mean difference about 10 mm Hg), higher diastolic blood pressure (10 mm Hg), higher heart rate (15 bpm), less respiratory sinus arrhythmia, shorter pulse transit time, and lower T-wave amplitude. Respiratory measures, electrodermal measures, body movement, and self-reported anxiety and excitement did not distinguish the groups. Reactivity to the stress tests was unaffected by the medications, but tonic differences present in the baseline persisted.

Validation and Evaluation of Test for Sympathetic Cholinergic Function in Diabetes Mellitus

Skin potential response (SPR), an electrodermal measure of sudomotor nerve function, was shown in this study to examine specifically sympathetic cholinergic fibers by abolition of the response during atropine infusion but not during propranolol infusion. The difference between responses in the left and right arms (SPR-D) was used to assess autonomic nerve function in 136 patients with diabetes and 52 control subjects. In 82% of the diabetic population (112 of 136), SPR-D was greater than 2SD above the mean control response compared with 42% (57 of 137) greater than 2SD below the mean control age-related value for a standard autonomic test predominantly of parasympathetic function, the R-R interval variation with breathing. Of 15 patients with clinical diabetic autonomic neuropathy, SPR wave forms were bizarre or absent in 5 patients compared with 18 of 121 patients' without clinical autonomic neuropathy (chi 2 = 3.5, P = 0.062). Measurement of SPR-D provides an easily determined measure of sympathetic cholinergic nerve function and may be a useful component of a group of tests for autonomic nerve function in diabetes.

Changes in the Electrodermal Activity of Schizophrenic Patients Associated with Change in the Expressed Emotion Status of Their Relatives

Thirty-nine relatives of schizophrenic patients, who had been rated as high on Expressed Emotion (EE) during the patients' admission for an acute episode, were re-rated on EE 9 months after discharge from the index admission. Electrodermal activity was recorded from the patient during a 15-min period when the relative was absent and a similar period while the relative was present. Recording took place during the index admission and at a 9-month follow-up. A comparison was made between those patients whose relatives remained high EE at follow-up (Stables) and those whose relatives change to low EE (Decreasers). No differences were apparent between these two groups, however, differences were found within groups. At admission both groups showed an increase in electrodermal measures from the relative-absent period to the relative-present period. At 9-month follow-up, the Stables still exhibited this direction of change, whereas the Decreasers showed a decrease in electrodermal activity between these periods.

Detection of guilty knowledge in real-life criminal investigations.

The present study provides a first attempt to estimate the validity of the Guilty Knowledge Test (GKT) in real-life criminal investigations. Skin resistance responses in GKT records of 50 innocent and 48 guilty Ss, for whom actual truth was established by confession, were analyzed by two methods. On the basis of an a priori decision rule, 98% of the innocent and 42% of the guilty Ss were correctly classified. Signal detection measures based on various possible decision rules indicated that the distribution of guilty Ss was highly differentiated from the distribution of innocent Ss. An optimal decision rule yielded correct classifications for 94% of the innocent Ss and 65% of the guilty Ss. These results suggest that the GKT could be a useful investigative tool that protects innocent suspects from being falsely classified as guilty. The false-negative identifications were accounted for in terms of the realistic conditions. Two main techniques of psychophysiological detection are used in field practice. The Control Question Technique (CQT; Reid & Inbau, 1977) is the most commonly used and the more controversial mainly because it uses questionable controls (e.g, Furedy & Heslegrave, in press; Lykken, 1974,1981). Other investigators (e.g, Raskin, 1978; Raskin & Kircher, in press; Raskin & Podlesny, 1979) have argued that the questions in the CQT were never intended to function as true experimental controls for relevant questions but rather to set up a situation wherein the innocent examinee, who is truthful concerning the relevant questions, will be more concerned about the controls. Therefore, the term control in the CQT is a misnomer. The Guilty Knowledge Test (GKT) is less frequently used in field practice, but it is based on genuine questions that differ from the relevant questions only with respect to the event under investigation. Therefore, its use has been recommended by many investigators (e.g., Ben-Shakhar, in press; Lykken, 1974,1981). The GKT has been the focus of research on psychophysiological detection since the early 1960s (Davidson, 1968; Giesen & Rollison, 1980; Lykken, 1959, I960; Podlesny & Raskin, 1978), and in some cases, excellent detection rates have been reported. In these studies, the electrodermal measure (which is relatively easy to quantify) was usually used for several multiple-item questions, and detection scores were based on differential responsivity to the relevant items across questions (e.g, Davidson, 1968; Lykken, 1959). All this research was conducted in laboratory settings, however, and used either cardtest or mock-crime procedures. The present study constitutes a first attempt to gather and analyze data based on the GKT as applied in field practice. The purpose of the GKT is to detect the presence of guilty knowledge by means of physiological measurements. During

Effects of Motivation and Verbal Response Type on Psychophysiological Detection of Information

Two independent experiments were designed to investigate the effects of motivation to deceive and the type of verbal response on psychophysiological detection using the Guilty Knowledge Technique. The first was a field experiment in which 72 subjects were randomly assigned to 8 experimental conditions. These conditions were created by a 2 x 4 factorial design (two motivational states crossed with four verbal response modes--affirming, denying, repeating, or no verbal response to questions about personal information). The second experiment was a laboratory experiment in which 160 students were assigned to the same 8 conditions. Results of both experiments indicated that highly motivated subjects were detected better than less motivated subjects. The act of lying was associated with enhanced differential responsivity, but no effects were obtained for verbal response versus no response or for variable versus standard verbal response. Differential responsivity tended to decline when questions were repeated. The first experiment revealed a clear advantage of electrodermal measures over respiration and cardiovascular measures. The results were discussed in relation to previous findings, a new theoretical formulation, and practical implications.

Methods and mechanisms in electrodermal omission responding: A commentary on stimulus omission and the orienting response by Barry and O'Gorman

Barry and O'Gorman (1987) have employed a response-averaging technique to demonstrate that electrodermal orienting responses (ORs) to omitted stimuli have unusually long latencies. They suggest that this latency delay provides evidence that omission ORs are “voluntary” responses initiated after a process of significance evaluation. The present commentary is addressed to both the methodological and theoretical aspects of their work. Firstly, some of the disadvantages of response averaging with electrodermal measures are reviewed, particularly as applied to omission ORs. Secondly, the use of OR latency as a dependent measure is discussed within an information-processing context. It is concluded that the assessment of stimulus significance does not systematically influence the latency of the OR. Hence, delayed latencies for omission responses probably reflect inaccuracies in the estimation of long inter-stimulus intervals, rather than a process of significance evaluation unique to the omission OR.

Effects of conditioned stimulus fear-relevance and preexposure on expectancy and electrodermal measures of human Pavlovian conditioning.

The present research investigated the effects of fear-relevance of the conditioned stimulus (CS) and CS preexposure on human electrodermal conditioning and on a continuous measure of expectancy of the unconditioned stimulus (US). Both experiments employed 20 preexposure, 8 acquisition, and 8 extinction trials in a differential Pavlovian conditioning paradigm with shock as the US. In Experiment 1 (N = 48), electrodermal conditioning was retarded by CS preexposure, but was not influenced by fear-relevance of the CS. Expectancy of the US was retarded by preexposure only in the fear-relevant condition. In Experiment 2 (N = 48), the CS/US contingencies was embedded in a visual masking task. Preexposure retarded both electrodermal conditioning and US expectancy. Neither measure was influenced by fear-relevance of the CS. However, fewer subjects in the preexposure condition learned the CS/US relationship and those who did, did so on later trial than those in the no-preexposure condition. Thus, the results indicated clear retardation of conditioning as a result of preexposure, but no reliable effect of fear-relevance.

The Relationship of Symptomatology and Medication to Electrodermal Activity in Schizophrenia

An electrodermal assessment procedure using mild innocuous tones, task-relevant tones, and loud white noise was administered to a sample of schizophrenic patients (n = 77). The present study investigated the relationship of schizophrenic symptomatology and anticholinergic level of neuroleptic medication to electrodermal variables. Each patient was evaluated for positive (florid) and negative (defect) symptoms. The neuroleptics that patients received were rated according to their anticholinergic effect. No significant differences in symptomatology were observed between electrodermal responders and nonresponders; however, nonresponders showed a nonsignificant tendency to have more positive and negative symptoms than responders. Both negative symptoms and anticholinergic levels were significant predictors of lower tonic levels of skin conductance. Patients receiving high anticholinergic neuroleptics showed significantly reduced measures of electrodermal responsivity and tonic levels. Thus, both symptomatology and type of neuroleptic are related to electrodermal measures, with the anticholinergic effect of neuroleptic medication being more pronounced.

Processing demands, effort, and individual differences in four different vigilance tasks.

In an attempt to specify the limiting conditions of the taxonomy of vigilance tasks, four tasks differing in memory load and in stimuli employed (sensory or cognitive) were compared. Electrodermal activity and subjective measures were used to determine the investment of effort. The data show that vigilance level and vigilance decrement dissociate. The level seems to relate to effort demand and investment; the decrement seems to be task driven, determined mainly by the type of stimuli used. Tasks employing unfamiliar stimuli showed a decline in sensitivity; "cognitive" tasks employing alphanumeric stimuli did not. Principal components analyses suggest that measures of speed and accuracy may reflect relatively independent systems. Subjective data showed that good performers expand more effort in difficult and complex tasks. Effortful processing seems to prevent rather than induce a decline in efficiency.

The Autonomic Nervous System Response Inventory (ANSRI): prediction of psychophysiological response.

An experiment was conducted to test the validity of the ANSRI by determining whether self-report of physiological response to emotion-provoking imagery could predict individuals' patterns of physiological response to the same imagery. Fifty two undergraduate volunteers completed the ANSRI and, 2 weeks later, reconstructed their original imagery (fear, anger, sadness, joy, activity situations) while seven physiological response systems were recorded polygraphically. The ANSRI scales for a condition (e.g. fear) were entered as predictors of each electrophysiological measure recorded under that condition in Stepwise Multiple Regression Analyses. Forty-nine percent of the analyses were statistically significant (mean R = 0.52; 27% of the variance). Every electrophysiological variable was significantly predicted by the ANSRI's scales under at least one imagery condition, or by using the mean response to items across the five conditions. Cardiovascular, respiration and electrodermal measures were predicted best. Every ANSRI P scale corresponding to an electrophysiological measure was a major variable in the significant prediction of that measure in at least one condition.

Electrodermal measures in schizophrenia: Episode or vulnerability indicators?

Electrodermal measures in schizophrenia: Episode or vulnerability indicators?

Clinical significance of the electrodermal habituation rate in anxiety disorders.

The electrodermal response habituation rate (EDR-HR) is examined in relation to clinical, personality and electrodermal measures in patients with generalized anxiety, phobic, obsessive-compulsive, dysthymic and conversion disorders by means of a stepwise regression analysis procedure. The results in the entire sample suggest that EDR-HR depends on the phasic component (amplitude and spontaneous activity) of the electrodermal response as well as on state anxiety, extraversion and depersonalization. When tested separately, most of the diagnostic groups demonstrated main trends similar to those found in total patients. A noteworthy correspondence between the importance of the contribution of certain clinical symptoms to the EDR-HR variance and some long-standing views of psychopathology was also found during the separate analysis of the groups. Although these findings question the diagnostic specificity of EDR-HR, the importance of this index as an objective measure of change following a therapeutic intervention as well as its potential usefulness in high-risk studies of anxiety disorders is put forward.

Effects of Cigarette Smoking on Bilateral Electrodermal Measures of the Orienting Reflex

ABSTRACTBilateral skin conductance was recorded in 6 male and 6 female smokers and in 6 male and 6 female nonsmokers on two different days. On the first day, a 10‐min rest period during which 3 male and 3 female smokers smoked a cigarette was followed by a taped series of common and uncommon innocuous tone stimuli to which evoked responses were measured. Nonsmokers did not smoke prior to presentation of the tones. On the second day, one week later, evoked responding was again measured during two further presentations of the tone stimuli after a 10‐min rest period during which the remaining smokers smoked a cigarette. During the first presentation, subjects listened to the tones as before. During the second presentation, subjects performed a pedal‐press whenever they heard the uncommon tone in the series. Results showed that smoking depressed responding to common and uncommon tones on the first day, but elevated responding to both tones on the second day during the passive listening phase. During the pedal‐press task, smoking selectively elevated responding to uncommon tones. Male smokers gave larger responses to uncommon tones in their left than right hands during the pedal‐press task, especially after smoking. Results are interpreted in terms of nicotine‐induced enhancement of the voluntary orienting reflex possibly mediated by the left frontal cortex.

The Assessment of Psychophysiological Reactivity to the Expressed Emotion of the Relatives of Schizophrenic Patients

The measure of expressed emotion (EE) of the relative has been found to be an important predictor of schizophrenic relapse. Electrodermal measures were recorded when the schizophrenic patient was talking to an experimenter, and when the patient was talking to a relative. Although there were no differences during the relative-absent period, patients with a high-EE relative present exhibited significantly higher frequencies of non-specific skin-conductance responses (NS-SCRs) than patients with a low-EE relative present. Patients show a significant decrease in NS-SCRs on the entry of low-EE, but not high-EE relatives. Patients with high-EE relatives show overall higher levels of skin-conductance levels (SCLs) than patients with low-EE relatives. Although patients with high-EE relatives rate themselves significantly more tense and anxious on self-rating scales, there are no significant correlations between self-ratings and electrodermal measures. The use of electrodermal reactivity as an assessment measure of relapse risk is discussed.

Effect of Biofeedback on the Detection of Deception

This study examined the effect of audio electrodermal biofeedback training on the detection of deception. The subjects consisted of 68 volunteers enrolled in selected undergraduate college courses. Each subject was required to commit a mock murder, after which a polygraph examiner administered a series of five consecutive "lie detector" tests to ascertain the facts involved in his/her murder. Before testing, subjects were randomly assigned to either a biofeedback condition or to a control group. The detection efficiency associated with the subject's respiration responses was significantly enhanced by simultaneous auditory biofeedback given during the polygraph testing; however, the feedback's effect upon the detection rates associated with the electrodermal measures that it was reflecting was neither statistically significant nor in the same direction. The results support the premise that audio biofeedback might be useful in enhancing respiration's detection efficiency during polygraph testing.

Another look at the relationship of electrodermal activity to electrode contact area.

ABSTRACTThe present study was undertaken lo reexamine the hypothesis that the relationship between skin conductance and electrode size is monotonic and linear. Skin conductance activity was recorded from 48 right‐handed male subjects using 6 different sixes of electrode collars ranging in exposed surface area from .131 cm2 to .786 cm2. The dependent measures were skin conductance level (SCL); skin conductance response (SCR) amplitude to a series of 8 loud tones; latency, rise time, and recovery half‐time of the first tone elicited response; (he largest self‐generated SCR; and the number of nonspecific responses. The results indicated a significant linear relationship between contact area and SCL, stimulus and self‐generated SCR amplitude, and the number of nonspecific responses. Latency was not affected by electrode size although the other time‐based measures were. Differences in skin conductance activity were found among different palmar recording sites. The observed linear relationship between electrode size and electrodermal measures has implications for current models of electrodermal activity and for the comparison of results across studies in which different electrode contact areas are used.

Changes in psychophysiological and conditioning variables during chlormethiazole-medicated and unmedicated ethanol withdrawal: preliminary report.

Autonomic lability during ethanol withdrawal in chlormethiazole-medicated and unmedicated groups was investigated using electrodermal measures. Vulnerability to Pavlovian aversive conditioning was also assessed. Ethanol withdrawal was associated with increased autonomic arousal and aversive conditioning, suggesting an increased risk of phobia acquisition. Chlormethiazole administered during ethanol withdrawal may protect against such developments.