Electrical Skin Conductance Research Articles

Defense-related emotions in humans.

The study of the role of serotonin in anxiety has led to the view that this neurotransmitter enhances anxiety, but inhibits panic. Validation of this hypothesis has been made using two experimental procedures that increase anxiety in human volunteers. One is classical conditioning of the skin electrical conductance response, which is assumed to represent anxiety. The other is simulated public speaking, which is believed to mobilize the same neural networks that are operative in panic and social anxiety disorders. In general, the results of these studies have fulfilled the predictions derived from the above hypothesis. The same procedures have been applied to panic disorder patients, and the obtained results have shown that these patients had a blunted anxiety response to public speaking. This speaking stress also did not activate the hypothalamic-pituitary-adrenal axis, which, in contrast, was activated by anticipatory anxiety. It may be concluded that anxiety and panic are qualitatively different emotional states, respectively related to the animal defense reactions to potential and proximal threat. In agreement, reported results of recent neuroimaging studies have shown that anxiety activates prefrontal cortical areas, whereas panic activates midbrain regions, particularly the periaqueductal gray matter. As a general conclusion, it may be said that anxiety, fear and panic do not belong to the same continuum of increasing intensity; instead, they are qualitatively different emotional states.

Monitoring Electrical Skin Conductance: A Tool for the Assessment of Postoperative Pain in Children?

Monitoring Electrical Skin Conductance: A Tool for the Assessment of Postoperative Pain in Children?

Monitoring electrical skin conductance: A tool for the assessment of postoperative pain in children?

Monitoring electrical skin conductance: A tool for the assessment of postoperative pain in children?

Depth profiling of Stratum corneum hydration in vivo: a comparison between conductance and confocal Raman spectroscopic measurements

The high-frequency electrical conductance of tape-stripped human skin in vivo can be used to evaluate the hydration profile of Stratum corneum (SC). Tape-stripping provides access to the underlying SC layers, and the conductance of these layers (as measured by the Skicon instrument) correlates well with their water content, as demonstrated by independent confocal Raman spectroscopic measurements. The correlation shows high inter-individual variance and is not linear over the full measurement range of the instrument, but is helpful to discriminate between dry, normal and highly hydrated SC. The depth profile of hydration in tape-stripped SC corresponds to the one in intact SC only if the barrier function of the skin is not impaired. Thus, conductometry of tape-stripped skin must be used in conjunction with a method that allows to estimate the barrier damage inflicted to SC during the tape-stripping procedure, for example, measurement of the trans-epidermal water loss. The methodology described here is simple, rapid and minimally invasive, and it employs commercially available instrumentation that is cheap, portable and easy to use. This approach is applicable to in vivo estimation of the SC hydration in studies in the areas of dermatology, skin care and transdermal drug delivery.

Monitoring Electrical Skin Conductance

Background Monitoring changes in electrical skin conductance has been described as a potentially useful tool for the detection of acute pain in adults. The aim of this study was to test the method in pediatric patients. Methods A total of 180 postoperative pediatric patients aged 1-16 yr were included in this prospective, blinded observational study. After arrival in the recovery unit, pain was assessed by standard clinical pain assessment tools (1-3 yr: Face Legs Activity Cry Consolability Scale, 4-7 yr: Revised Faces Scale, 8-16 yr: Visual Analogue Scale) at various time points during their stay in the recovery room. The number of fluctuations in skin conductance per second (NFSC) was recorded simultaneously. Results Data from 165 children were used for statistical analysis, and 15 patients were excluded. The area under the Receiver Operating Characteristic curve for predicting moderate to severe pain from NFSC was 0.82 (95% confidence interval 0.79-0.85). Over all age groups, an NFSC cutoff value of 0.13 was found to distinguish between no or mild versus moderate or severe pain with a sensitivity of 90% and a specificity of 64% (positive predictive value 35%, negative predictive value 97%). Conclusions NFSC accurately predicted the absence of moderate to severe pain in postoperative pediatric patients. The measurement of NFSC may therefore provide an additional tool for pain assessment in this group of patients. However, more research is needed to prospectively investigate the observations made in this study and to determine the clinical applicability of the method.

Developments in autonomic research: a review of the latest literature

In addition to its homeostatic role, the autonomic nervous system is responsible for generating many of the outward signs of our emotions: our tears, our racing heart, our cold sweat. While mental stress causes an increase in heart rate and sweat release, viewing emotionally charged images—especially negative images—causes a decrease in heart rate. Children with autism spectrum disorder show increases in skin conductance (sweat release) when presented with images of faces, but their capacity to recognize faces is compromised. Conversely, children with Williams syndrome, who are very interested in faces and are socially very engaging, show blunted sudomotor responses to faces and show decreases in heart rate. Many studies have used emotionally charged visual stimuli to induce autonomic responses, and changes in electrical skin conductance as a convenient marker of autonomic arousal, to examine the brain structures involved in emotional processes. Such studies have shown that the amygdala is strongly activated during exposure to fearful images, whereas the nucleus accumbens responds strongly to erotic or romantic images (and is deactivated when exposed to negative images). Given that the nucleus accumbens forms part of the reward circuitry, it is perhaps not surprising that it is activated during that most pleasurable of autonomic acts, orgasm.

Monitoring electrical skin conductance: a tool for the assessment of postoperative pain in children?

Funding: Princess Margaret Hospital Foundation, Perth, AustraliaThe manuscript has been written and checked according to the STROBE consensus.Objectives: To test whether changes in electrical skin conductance are a suitable tool for the assessment of postoperative pain in paediatric patients.Design: Prospective, blinded observational study.Setting: Recovery room Department of Anaesthesia, Princess Margaret Hospital for Children, Australia.Participants: A total of 180 postoperative paediatric patients aged 1–16 years.Main Outcome Measures: Area under the curve (ROC) for the skin conductance parameter ‘number of fluctuation per second’ (NFSC) to distinguish between no or mild vs moderate or severe postoperative pain (obtained by standard pain scores).Results: Postoperative pain was assessed in 165 children (1–16 years) by standard validated clinical pain assessment tools (Revised Faces Scale, FLACC Scale, Visual Analogue Scale) at various time points during their stay in the recovery room. NFSC was recorded simultaneously. Fifteen patients were excluded due to technical problems with monitoring NFSC. The area under the Receiver Operating Characteristic (ROC) curve for predicting moderate to severe pain from NFSC was 0.82 (95% CI, 0.79–0.85). Over all age groups, a NFSC cut‐off value of 0.13 was found to distinguish between no or mild vs moderate or severe pain with a sensitivity of 90% and a specificity of 64% (positive predictive value 35%, negative predictive value 97%).Conclusion: NFSC accurately predicts moderate to severe pain in postoperative paediatric patients. In this group of patients, the measurement of NFSC may therefore be a useful addition to the presently used, clinical pain assessment tools.Trial Registration: Australian Clinical Trials Register (ACTRN12607000474459)

Synergistic enhancement of skin permeability by N-lauroylsarcosine and ethanol

To develop formulations for transdermal drug delivery, this study tested the hypothesis that the anionic surfactant, N-lauroylsarcosine (NLS), and ethanol synergistically increase skin permeability by increasing the fluidity of stratum corneum lipid structure. Skin permeability experiments showed that transdermal delivery of fluorescein across human cadaver epidermis was increased by up to 47-fold using formulations containing NLS in aqueous ethanol solutions. Skin permeability was increased by increasing NLS concentration in combination with 25–50% ethanol solutions. Skin permeability was shown to correlate with skin electrical conductivity measurements, changes in differential scanning calorimetry lipid transition peak temperature, and Fourier transform infrared spectroscopy C H stretching peak shifts indicative of stratum corneum lipid fluidization and changes in protein conformation. Evidence for lipid extraction was also evident, but did not appear to be responsible for the observed increases in skin permeability. We conclude that NLS in aqueous ethanol formulations can dramatically increase skin permeability by a mechanism involving synergistic lipid-fluidization activity in the stratum corneum.

Ansiedade experimental humana

CONTEXTO: A ansiedade experimental no ser humano constitui-se em ponte entre os modelos animais e os ensaios clínicos. OBJETIVO: Este artigo focaliza métodos químicos e psicológicos utilizados para provocar ansiedade experimental em seres humanos. MÉTODOS: Realizou-se revisão seletiva da literatura. RESULTADOS: Os desafios farmacológicos têm sido usados principalmente para induzir ataques de pânico em pacientes com transtorno de pânico, os quais são mais sensíveis a eles que indivíduos normais ou pacientes portadores de outros transtornos psiquiátricos. Uma das mais importantes contribuições deste método é a de ter mostrado que os agentes panicogênicos mais seletivos, como o lactato ou a inalação de CO2, não ativam o eixo hormonal do estresse. Entre os métodos psicológicos, destacam-se o condicionamento de respostas elétricas da condutância da pele, cujo perfil farmacológico se aproxima daquele do transtorno de ansiedade generalizada, e o teste da simulação do falar em público, cuja farmacologia é semelhante à do transtorno de pânico. CONCLUSÕES: Tais resultados salientam a diferença entre a neurobiologia da ansiedade e a do pânico.

Critique of ‘Control of arterial PCO2 by somatic afferents’

Critique of ‘Control of arterial <i>P</i>_CO2 by somatic afferents’

Investigation of properties of human epidermal membrane under constant conductance alternating current iontophoresis

Previous studies in our laboratory have shown that enhanced, constant permeant fluxes across human skin can be achieved by applying an alternating current (AC) to maintain skin electrical conductance at a constant level. Relative to conventional direct current (DC) iontophoresis, for which current is maintained at a constant level, this newly developed constant conductance alternating current (CCAC) method achieves constant fluxes with less inter- and intra-sample variability. The present study focused upon further investigating the permeability properties of human skin during CCAC iontophoresis at a variety of target resistance/conductance values. A three-stage experimental protocol was used with flux measurements determined on 3 consecutive days. Stage I was an AC only protocol (symmetrical AC square-wave signal), stage II was an AC plus DC protocol (AC square-wave with DC offset voltage), and stage III was a repeat of stage I. During this three-stage protocol, the skin electrical resistance was maintained at a constant target value by manually adjusting the applied AC voltage. Radiolabeled mannitol and urea were model permeants in all experiments. Their fluxes were determined and used to characterize the permeability properties of human skin. The results from the present study established that: (i) the CCAC protocol made it possible to reduce HEM electrical resistance to different target levels as low as 0.8 kΩ cm 2 and maintain the specific resistance level throughout the flux experiment, (ii) permeant fluxes are proportional to skin electrical conductance, (iii) under the studied CCAC passive conditions, membrane pore size tends to increase as skin resistance decreases, and (iv) as the membrane breaks down, its pore sizes become larger.

An investigation of the role of cavitation in low-frequency ultrasound-mediated transdermal drug transport.

Low-frequency ultrasound (20 kHz) has been shown to increase the skin permeability to drugs, a phenomenon referred to as low-frequency sonophoresis (LFS). Many previous studies of sonophoresis have proposed that ultrasound-induced cavitation plays the central role in enhancing transdermal drug transport. In this study, we sought to definitively test the role of cavitation during LFS, as well as to identify the critical type(s) and site(s) of cavitation that are responsible for skin permeabilization during LFS. Pig full-thickness skin was treated by 20 kHz ultrasound and the effect of LFS on the skin permeability was monitored by measuring the increase in the skin electrical conductance. A high pressure LFS cell was constructed to completely suppress cavitation during LFS. An acoustic method, as well as chemical and physical dosimetry techniques, was utilized to monitor the cavitation activities during LFS. The study using the high-pressure LFS cell showed definitively that ultrasound-induced cavitation is the key mechanism via which LFS permeabilizes the skin. By selectively suppressing cavitation outside the skin using a high-viscosity coupling medium, we further demonstrated that cavitation occurring outside the skin is responsible for the skin permeabilization effect, while internal cavitation (cavitation inside the skin) was not detected using the acoustic measurement method under the ultrasound conditions examined. Acoustic measurement of the two types of cavitation activities (transient vs. stable) indicates that transient cavitation plays the major role in LFS-induced skin permeabilization. Through quantification of the transient cavitation activity at two specific locations of the LFS system, including comparing the dependence of these cavitation activities on ultrasound intensity with that of the skin permeabilization effect, we demonstrated that transient cavitation occurring on, or in the vicinity of, the skin membrane is the central mechanism that is responsible for the observed enhancement of skin permeability by LFS. LFS-induced skin permeabilization results primarily from the direct mechanical impact of gas bubbles collapsing on the skin surface (resulting in microjets and shock waves).

Sweat gland function as a measure of radiation change

Background: Radiotherapy may result in dryness of the skin even when no other change can be detected. We describe a system for recording the electrical conductance of skin as a measure of sweat gland function. Patients and methods: In 22 normal volunteers close agreement was obtained between measurements obtained from comparable sites on both sides of the chest. Measurements were subsequently made in 38 patients treated by radiotherapy to one side of the chest for tumours of the breast or lung using one of five different fractionation schedules. Simultaneous readings were obtained from both sides of the chest with the non irradiated side acting as a control. Results: A dose response relationship was demonstrated: five patients who received the equivalent total dose of 15 Gy in 2-Gy fractions showed no change in conductance. Sixteen out of 23 who received an equivalent total dose of 42–46 Gy in 2-Gy fractions had a greater than 22% reduction in mean skin conductance compared with that of the control areas despite the skin appearing normal in the large majority. Marked changes in skin conductance were seen after higher total doses. In a prospective study 18 women receiving breast irradiation underwent weekly readings during treatment. A mean reduction of 40% in skin conductance was noted by the end of the second week of treatment prior to any clinical evidence of radiation change. Skin conductance returned to normal in 44% of patients by 6 months. In the remainder, those patients who showed the greatest reduction in skin conductance during treatment demonstrated the least recovery. Conclusions: Changes in sweat gland function can be detected and quantified in skin which may otherwise appear normal. Differences may so be demonstrated between areas treated using different fractionation schedules and the method may be applied to the detection during radiotherapy of unusually sensitive patient

The Effects of Three Kinds of Yoga Exercises on Skin Electrical Conductivity of Meridians and Respiro-Circulatory Functions

The Effects of Three Kinds of Yoga Exercises on Skin Electrical Conductivity of Meridians and Respiro-Circulatory Functions

The correlation between skin electrical conductance and the score of qi vacuity.

In traditional Chinese medicine, the syndrome of qi vacuity means that the patient's body has a low level of energy to react to stress. Recently, we used a score, the QV score, by scaling the severity of symptoms and signs of qi vacuity in patients with tiredness. The aim of this study was to investigate the relationship between QV score and skin electrical conductance in patients with tiredness. One hundred and forty-three healthy controls and 103 patients with tiredness were involved. Each subject received a weak electrical stimulation with constant voltage (1.75 volt), and conductance was measured between two different limbs. The mean value of skin conductance among four limbs was calculated and expressed by a special unit, namely Chin. The correlation between the skin conductance and QV score was analyzed by a linear regression analysis. The results showed that skin electrical conductance of healthy controls was negatively correlated with age (r-coefficient = -0.51, P = 0.000). The skin conductance of patients with tiredness was significantly lower than that of healthy controls with matching age (P = 0.000 by Student's t-test). Moreover, there was a positive correlation between the decrease of skin conductance and the QV score in patients with tiredness (r-coefficient = +0.68, P = 0.000). These results suggest that a decrease in skin electrical conductance may be closely related to the severity of qi vacuity. The skin conductance test is a simple, reliable, and quantitative method for detection of syndrome of qi vacuity.

Effect of d -fenfluramine on human experimental anxiety

To investigate the role of 5-HT in human anxiety, the 5-HT releaser and uptake blocker d-fenfluramine (FEN) was administered to healthy volunteers under two models of experimental anxiety. The first was a simulated public speaking (SPS) test consisting of talking in front of a video camera, anxiety being evaluated mainly by self-rating scales. The second was a conditioned fear test, in which the changes in skin electrical conductance caused by a tone associated once with an aversive white noise were measured. The doses of 15 and 30 mg FEN, PO, decreased anxiety induced by SPS in a dose-dependent way, as indicated by the anxiety factor of Norris Visual Analogue Mood Scale. In the conditioned fear test, however, the amplitude and level of skin conductance responses to the conditioned aversive stimulus were not significantly changed by FEN. The differential effects of FEN in these human experimental models of anxiety, together with similar results reported in rats, support the view that 5-HT exerts a dual action on brain mechanisms regulating anxiety, facilitating conditioned while inhibiting unconditioned fear. The presumed reduction in unconditioned fear caused by FEN may have implications for the treatment of panic disorder.

Influence of force on muscle and skin sympathetic nerve activity during sustained isometric contractions in humans.

1. Our purpose was to test the hypothesis that efferent sympathetic nerve activity to non-active skeletal muscle (MSNA) and skin (SSNA) is independent of the level of force during sustained submaximal isometric contractions in humans. 2. In twelve healthy subjects, arterial blood pressure, heart rate, and MSNA (n = 6) or SSNA (n = 6) (peroneal microneurography) were recorded before and during isometric handgrip contractions sustained to exhaustion at 20, 40 and 60% of maximal force. Responses were examined at similar percentages of endurance time at each level of force. 3. Contraction duration decreased progressively with increasing force (495 +/- 54, 140 +/- 13, 73 +/- 8 s, respectively), but peak ratings of perceived effort were similar for the three force levels. 4. The peak increases in systolic pressure were not different among the three levels of force. The increases in diastolic and mean pressure were similar at 40 and 60% of maximal force, but were smaller at the end of 20% of maximal force. The contraction-induced rise in heart rate was directly related to the level of force. 5. The contraction-evoked stimulation of both MSNA and SSNA was similar during handgrip at 40 and 60% of maximal force, but was much less during handgrip at 20% of maximal force. The increases in SSNA were associated with increases in both skin blood flow and skin electrical conductance suggesting primarily sudomotor fibre activation. 6. These findings indicate that there is a minimum force necessary to elicit peak levels of MSNA and SSNA during sustained isometric contractions in humans. When normalized to endurance time, however, the regulation of these sympathetic outflows appears to be independent of force above this minimum level. The results also indicate that during this type of muscle activity the relationship between force and heart rate is different to that between force and peripheral sympathetic discharge.

Stress Goes to the Dogs

D ogs do more than shed on the rug, bark at prowlers and provide reliable companionship. Sometimes the presence of a canine comrade acts as a natural sedative for its human master, lowering blood pressure and other bodily responses to stress while fostering improved performance on a difficult task, according to results from a new study of women and their dogs. Having a human friend close at hand while attempting the same task heightens the body's stress reactions and undermines performance, assert psychologists Karen M. Allen and James J. Blascovich, both of the State University of New York at Buffalo. Dogs take a bite out of stress because they provide unconditional support without scrutinizing their owner's sometimes frantic attempts to meet a challenge, Allen and Blascovich argue. A two-legged friend, harboring the human propensity to evaluate the success or failure of others, tends to stoke anxiety and embarrassment in the same situation. The new findings reported in the October JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY add to other indications that pets often help to buffer their owners from stress and illness. For example, in a 1980 study of 96 people with heart disease released after treatment at a coronary-care unit, psychiatrist Erika Friedmann of the University of Pennsylvania in Philadelphia and her co-workers identified a higher survival rate one year after hospital discharge among pet owners, even after accounting for individual differences in the extent of heart damage and other medical problems. In fact, having a pet at home proved a stronger predictor of survival than having a spouse or extensive family support, Friedmann's team found. In another investigation, 345 elderly pet owners cited proportionately fewer physician visits over one year than did 593 same-aged counterparts with no pets, psychologist Judith M. Siegel of the University of California, Los Angeles, reported in the June 1990 JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY. Pet owners told Siegel that their animals offered substantial comfort in times of stress. However, only dog owners showed no tendency to visit physicians more often following stressful experiences, such as the death of a close friend or spouse. Dogs, more than other pets, provided their owners with companionship and an object of attachment, Siegel concludes. Other studies have charted blood presA llen and Blascovich probed the calming influence of canines among 45 women faced with a standard psychology-lab challenge performing mental arithmetic. All the women owned dogs and described themselves as dog lovers. In an initial laboratory session, the psychologists measured blood pressure, pulse rate and electrical skin conductance as each participant sat with a female researcher and rapidly counted backwards from a four-digit number by threes for two minutes. After a break, they repeated the exercise, counting backwards from a new number by sevens. The mental arithmetic produced consistent jumps in the physical measures of stress. Two weeks later, a more difficult arithmetic challenge-counting backwards by 13s and 17s took place at each participant's home. The experimenters randomly assigned women to perform the tasks in the company of only the researcher or with the addition of either their dog or their closest female friend. With Fido at foot, physical stress markers during mental calculations showed little change from their levels during a pre-test rest period the same day. With only an experimenter sitting nearby, stress measures displayed moderate increases, and the presence of a female friend dramatically boosted the same measures. In addition, participants accompanied by a friend performed mental arithmetic much more rapidly but less accurately than women in the other two groups and suffered a marked drop in accuracy from the previous laboratory session. The women apparently perceived their dogs as less threatening than friends or Researchers sniff out the calming effects of canines

Spontaneous fluctuations of electrical skin conductance and the actual clinical state in schizophrenics.

The present paper examines in a group of 48 schizophrenics, whether spontaneous fluctuations (SF) in electrical skin conductance show a relationship to psychiatric symptomatology. Subjects participated in an experiment that delivered nonsignal auditory stimuli. Their clinical state was assessed by the Brief Psychiatric Rating Scale (BPRS) and the Nurses' Observation Scale for Inpatient Evaluation (NOSIE). An additional set of factors with a possible influence on SF rates was also taken into account. A stepwise regression analysis showed BPRS Activation and NOSIE Manifest Psychosis to be of significance, the BPRS subscale displaying a positive and the NOSIE subtest a negative partial correlation to SF frequency. Results are discussed with regard to their implication for experiments using tonic electrodermal measurement; they are also compared with the literature on phasic electrodermal arousal.

Kinetic studies on the effects of ouabain on Na+ fluxes in frog skin.

Among 48 pieces of paired frog skins of Rana pipiens in Ringer's solution, 10 pieces showed a strictly monotone decrease in the short circuit current (SCC) following ouabain treatment (10(-4) M). In 9 cases a transient attenuation, and in 27 cases a distinct wave in the ebb of the SCC, was seen. In 2 instances, two waves were seen. Associated with the not-monotone events was a transient rise in electrical skin conductance. The reasons for these mixed skin responses are unknown. One possible reason is considered here: Early during the ouabain action, some of the Na+ entering from the mucosal side is trapped in the skin by electroneutral processes, in keeping with the already known fact that ultimately cellular KCl is partly replaced by NaCl. Computer assisted model studies show how monotone, and not-monotone "transepithelial" net Na+ flux curves can be generated. Essential conditions for the generation of not-monotone Na+ flux curves are: 1. Presence of two distinct "cellular", active Na+ pools in the model. 2. Presence of a loop pathway in which a principal "transepithelial Na+ transport compartment", and a constituent "Na+/K+ maintenance compartment", are connected to each other and to the "extracellular" compartment. The model, then, predicts under which kinetic conditions monotone and not-monotone transepithelial Na+ flux curves will be seen.