Changes In Electrodermal Activity Research Articles

Wrist-Worn Electrodermal Activity as a Novel Neurophysiological Biomarker of Autonomic Symptoms in Spatial Disorientation.

Background: Spatial disorientation is one of the most frequent causes of aircraft accidents, and is thus a major problem affecting air safety. Although a number of studies have examined spatial disorientation, the precise physiological changes occurring as a direct result of spatial disorientation and motion sickness remain unclear. The present study sought to investigate electrodermal activity (EDA) and subjective autonomic symptoms during spatial disorientation training, and to develop an indicator of physiological changes for pilot candidates.Methods: In the current study, we investigated changes in EDA measured using a wrist-worn device, and subjective autonomic nervous system symptoms during spatial disorientation training for pilot candidates. We then used the Graybiel diagnostic criteria to develop a novel physiological biomarker.Results: We found that maximum EDA change and peak amplitude were significantly increased in participants with a Graybiel score of ≥3 points compared with those who scored < 2 points. Furthermore, for symptoms of cold sweating and saliva secretion (from the seven Graybiel diagnostic criteria), the maximum EDA change in participants with scores ≥1 point was significantly higher than that of participants scoring 0 points.Conclusion: Our results indicate that EDA data measured with a wrist-worn device could provide a useful method for objective evaluation of the severity of spatial disorientation and motion sickness.

A Multimodal Exploration of Engineering Students' Emotions and Electrodermal Activity in Design Activities

AbstractBackgroundThis exploratory study uses multimodal approaches to explore undergraduate student engagement via topic emotions and electrodermal activity (EDA) in different engineering design method activities and with different instructional delivery formats (e.g., lecture vs. active learning).Purpose/HypothesisThe goal of this research is to improve our understanding of how students respond, via engagement, to their engineering design activities during class. This study hypothesizes that students would experience no self‐reported mean changes in topic emotions from their preassessment scores for each engineering design topic and instructional format nor would electrodermal activities (EDA) associate to these topic emotions throughout the design activities.Design/MethodEighty‐eight freshmen engineering students completed online pretopic and posttopic emotions surveys for five engineering design activities. A subset of 14–18 participants, the focal point of this study, wore an EDA sensor while completing the surveys and participating in these sessions.ResultsPreliminary findings suggest that EDA increased for individual and collaborative active learning activities compared to lectures. No significant changes in EDA were found between individual and collaborative active learning activities. Moderate negative correlations were found between EDA and negative topic emotions in the first engineering design activity but not across the rest. At the end of the semester, active learning activities showed higher effect sizes indicating a re‐enforcement of students' engagement in the engineering design method activities.ConclusionThis study provides initial results showing how multimodal approaches can help researchers understand students' closer‐to‐real‐time engagement in engineering design topics and instructional delivery formats.

Combat Exposure Blunts Sympathetic Response to Acute Exercise Stress in Explosive Ordnance Disposal Personnel

Electrodermal activity (EDA) is a valid proxy of sympathetic nervous system activity during exercise and thus possesses the translational potential for studying the effects of acute and chronic stress. PURPOSE: To evaluate the effect of combat exposure (CE) on the EDA response to acute exercise stress in chronically stressed military men. METHODS: Thirty-six healthy military men (mean age: 37.0±6.9 yr) completed a graded exercise test to assess maximal oxygen consumption (VO2max). EDA was recorded at baseline and during exercise (25, 50, 75, 100% VO2max) and recovery. A tertile split of CE levels established three exposure groups: low CE (n=12), medium CE (n=12), and high CE (n=12). A 3 (group) × 6 (stage) repeated-measures analysis of variance evaluated EDA changes across stages of exercise, as well as between CE levels. RESULTS: Baseline EDA values for high, medium, and low CE did not differ (p>0.05). From 25% to 100% VO2max, mean percent changes in EDA from baseline were +85.2 to +121.6%, with a subsequent decline in seated recovery (+105.8%) (p<0.001, ηp2 =0.28). An interaction between CE and exercise workload was observed (p=0.022, ηp2 =0.13). Specifically, low CE displayed a steep linear increase in EDA from 25% to 100% VO2max, followed by a steady decrease into recovery. In contrast, the high CE EDA response was blunted, with a peak occurring at 75% VO2max, after which it declined through 100% VO2max. The medium CE EDA response mirrored low CE until 75% VO2max, and then declined through seated recovery. CONCLUSION: Dose-dependent effects of CE were demonstrated on EDA response to exercise stress. The low-CE pattern is consistent with the literature characterizing healthy plasma catecholamine responses during exercise stress, as well as with our prior research illustrating EDA responses in aerobically fit individuals. High- CE individuals, by contrast, exhibit a less adaptive response. Collectively, these findings imply that CE disrupts the sympathetic response to acute exercise stress.

Electrodermal Activity during Blood Pooling for Arterial Blood Gases Analysis in Sedated Adult Intensive Care Unit Patients.

Electrodermal activity (EDA) is considered a measure of autonomous nervous system activity. This study performed an exploratory analysis of the EDA changes during blood pooling for arterial blood gas analysis in sedated adult critical care patients and correlated the variations to other monitored parameters. EDA, along with other parameters, were monitored during 4 h routine daytime intensive care nursing and treatment in an adult ICU. 4 h measurements were divided into two groups based upon the sedation level. Selected recordings before and after blood pooling for arterial blood gases analysis (stress event) was performed. Nine stress events from Group A and 17 from Group B were included for further analysis. Patients’ demographics, laboratory exams, and severity scores were recorded. For both sedation levels, EDA changes are much greater than any other monitoring parameters used. The changes are noticed in both measurement (15 s and 60 s), even though in the 60 s measurement only selected EDA parameters are significantly changed after the start of the procedure. EDA measurements are more sensitive to a given stress event than cardiovascular or respiratory parameters. However, the present results could only be considered as a pilot study. More studies are needed in order to identify the real stress-load and clinical significance of such stimuli, which are considered otherwise painless in those patients.

Electrodermal Activity Monitoring during Endotracheal Suction in Sedated Adult Intensive Care Unit Patients.

Endotracheal suctioning of respiratory secretions is one of the most common causes of pain and discomfort in Intensive Care Unit environment. The electrical properties of the skin, also known as electrodermal activity (EDA), are considered as an indirect measure of autonomous nervous system. This study explores EDA changes during endotracheal suction in sedated adult critical care patients; and compares these changes to other monitoring parameters. Skin conductance variability, selected hemodynamic and respiratory parameters, bispectral index (BIS) and ambient noise level, were monitored during 4 hour routine daytime intensive care nursing and treatment in an adult Intensive Care Unit. 4h-measurements were divided into 2 groups, based upon the sedation level (group A: Ramsay sedation scale 2-4 and group B: 5-6 respectively) of the patients. Selected recordings before and after endotracheal suction (stress events) were performed. Seven stress events from Group A and 17 from Group B were included for further analysis. Patients' demographics, laboratory exams and severity scores were recorded. Pain status evaluation before every event was also performed via 2 independent observers. In both groups the rate of EDA changes was greater than in other monitoring parameters. Yet, in group A only selected parameters were significantly changed after the start of the procedure, while in group B, every parameter showed significant change (p<0.05). Groups were similar for other co-founding factors. EDA measurements are more sensitive to stress stimuli, than cardiovascular, respiratory or even BIS monitoring. Deeper sedation seems to affect more the intensity of EDA changes during suction.

Simple, Transparent, and Flexible Automated Quality Assessment Procedures for Ambulatory Electrodermal Activity Data.

Electrodermal activity (EDA) is a noninvasive measure of sympathetic activation often used to study emotions, decision making, and health. The use of "ambulatory" EDA in everyday life presents novel challenges-frequent artifacts and long recordings-with inconsistent methods available for efficiently and accurately assessing data quality. We developed and validated a simple, transparent, flexible, and automated quality assessment procedure for ambulatory EDA data. A total of 20 individuals with autism (5 females, 5-13 years) provided a combined 181 h of EDA data in their home using the Affectiva Q Sensor across 8 weeks. Our procedure identified invalid data using four rules: First, EDA out of range; second, EDA changes too quickly; third, temperature suggests the sensor is not being worn; and fourth, transitional data surrounding segments identified as invalid via the preceding rules. We identified invalid portions of a pseudorandom subset of our data (32.8 h, 18%) using our automated procedure and independent visual inspection by five EDA experts. Our automated procedure identified 420 min (21%) of invalid data. The five experts agreed strongly with each other (agreement: 98%, Cohen's κ: 0.87) and, thus, were averaged into a "consensus" rating. Our procedure exhibited excellent agreement with the consensus rating (sensitivity: 91%, specificity: 99%, accuracy: 92%, κ: 0.739 [95% CI = 0.738, 0.740]). We developed a simple, transparent, flexible, and automated quality assessment procedure for ambulatory EDA data. Our procedure can be used beyond this study to enhance efficiency, transparency, and reproducibility of EDA analyses, with free software available at http://www.cbslab.org/EDAQA.

Emotional reactivity and comprehension of multiple online texts

This study investigates the role of students' dispositional emotion reactivity in the comprehension of conflicting online information about the topic of health risks associated with the use of mobile phones. Arousal was measured by changes in electrodermal activity as a physiological response to an emotionally negative school-related video. Emotional valence was assessed by self-reports. One hundred and four 7th graders read six texts about the topic in websites varying for reliability and position. After reading, a sentence verification test assessed surface comprehension within texts, while a short essay assessed their comprehension across them at intertextual level, including sourcing and argumentation. Results revealed that two reliably distinct profiles of emotional response, high reactive and low reactive, emerged from a cluster analysis when considering both arousal and valence of emotionality. These profiles differentiated intertextual comprehension at sourcing level, while controlling for possible interfering variables. Low reactive students outperformed high reactive students for the ability to refer to source information and to connect it to the content provided. Findings indicate the importance of student differences in emotional reactivity in a common comprehension task in the digital era.

Sleep Deprivation in Young and Healthy Subjects Is More Sensitively Identified by Higher Frequencies of Electrodermal Activity than by Skin Conductance Level Evaluated in the Time Domain.

We analyzed multiple measures of the autonomic nervous system (ANS) based on electrodermal activity (EDA) and heart rate variability (HRV) for young healthy subjects undergoing 24-h sleep deprivation. In this study, we have utilized the error awareness test (EAT) every 2 h (13 runs total), to evaluate the deterioration of performance. EAT consists of trials where the subject is presented words representing colors. Subjects are instructed to press a button (“Go” trials) or withhold the response if the word presented and the color of the word mismatch (“Stroop No-Go” trial), or the screen is repeated (“Repeat No-Go” trials). We measured subjects' (N = 10) reaction time to the “Go” trials, and accuracy to the “Stroop No-Go” and “Repeat No-Go” trials. Simultaneously, changes in EDA and HRV indices were evaluated. Furthermore, the relationship between reactiveness and vigilance measures and indices of sympathetic control based on HRV were analyzed. We found the performance improved to a stable level from 6 through 16 h of deprivation, with a subsequently sustained impairment after 18 h. Indices of higher frequencies of EDA related more to vigilance measures, whereas lower frequencies index (skin conductance leve, SCL) measured the reactiveness of the subject. We conclude that indices of EDA, including those of the higher frequencies, termed TVSymp, EDASymp, and NSSCRs, provide information to better understand the effect of sleep deprivation on subjects' autonomic response and performance.

Towards unravelling the relationship between on-body, environmental and emotion data using sensor information fusion approach

Over the past few years, there has been a noticeable advancement in environmental models and information fusion systems taking advantage of the recent developments in sensor and mobile technologies. However, little attention has been paid so far to quantifying the relationship between environment changes and their impact on our bodies in real-life settings.In this paper, we identify a data driven approach based on direct and continuous sensor data to assess the impact of the surrounding environment and physiological changes and emotion.We aim at investigating the potential of fusing on-body physiological signals, environmental sensory data and on-line self-report emotion measures in order to achieve the following objectives: (1) model the short term impact of the ambient environment on human body, (2) predict emotions based on-body sensors and environmental data.To achieve this, we have conducted a real-world study ‘in the wild’ with on-body and mobile sensors. Data was collected from participants walking around Nottingham city centre, in order to develop analytical and predictive models.Multiple regression, after allowing for possible confounders, showed a noticeable correlation between noise exposure and heart rate. Similarly, UV and environmental noise have been shown to have a noticeable effect on changes in ElectroDermal Activity (EDA). Air pressure demonstrated the greatest contribution towards the detected changes in body temperature and motion. Also, significant correlation was found between air pressure and heart rate.Finally, decision fusion of the classification results from different modalities is performed. To the best of our knowledge this work presents the first attempt at fusing and modelling data from environmental and physiological sources collected from sensors in a real-world setting.

Objective Measurement of Clinical Competency in Surgical Education Using Electrodermal Activity

Within the realm of surgical education, there is a need for objective means to determine surgical competence and resident readiness to operate independently. We propose a novel, objective method of assessing resident confidence and clinical competence based on measurement of electrodermal activity (EDA) during live surgical procedures. We hypothesized that with progressive training, EDA responses to the stress of performing surgery would exhibit decline, elucidating an objective correlate of clinical competence. EDA was measured using galvanic skin response sensors worn by residents performing laparoscopic cholecystectomy on sequential live human patients over an 8-month period. Baseline, phasic (peak) and tonic EDA responses were measured as a fractional change from baseline. University of Missouri, Columbia, Missouri, an academic tertiary care facility. Fourteen categorical general surgery residents and 5 faculty surgeons were voluntarily enrolled and participated through completion. Tonic fractional change (FCTONIC) was highest in PGY3 residents compared with postgraduate year (PGY) 1 and 2 residents (7.199 vs. 2.100, p = 0.004, 95% CI: 8.58-1.61 and PGY4 and 5 residents (7.199 vs. 2.079, p = 0.002, 95% CI: 8.38-0.29). Phasic fractional change in EDA (FCPHASIC) exhibited a progressive decline across resident training levels, with PGY1 and 2 residents having the highest response, and faculty displaying the lowest FCPHASIC responses. Statistical differences were seen between FCPHASIC faculty and PGY4 and 5 (3.596 vs. 6.180, p = 0.004, 95% CI: 0.80-4.36), PGY4 and 5, and PGY3 (6.180 vs. 15.998, p = 0.003, 95% CI: 3.33-16.3), as well as among all residents and faculty (13.057 vs. 3.596, p = 0.004, 95% CI: 15.8-3.1). Phasic EDA changes decrease with increasing clinical competence. For those participants with the lowest and highest levels of competence, tonic EDA changes are minimal. Tonic EDA changes follow an inverse-U shape with differing levels of clinical competence.

An efficient automatic workload estimation method based on electrodermal activity using pattern classifier combinations

Automatic workload estimation has received much attention because of its application in error prevention, diagnosis, and treatment of neural system impairment. The development of a simple but reliable method using minimum number of psychophysiological signals is a challenge in automatic workload estimation. To address this challenge, this paper presented three different decomposition techniques (Fourier, cepstrum, and wavelet transforms) to analyze electrodermal activity (EDA). The efficiency of various statistical and entropic features was investigated and compared. To recognize different levels of an arithmetic task, the features were processed by principal component analysis and machine-learning techniques. These methods have been incorporated into a workload estimation system based on two types: feature-level and decision-level combinations.The results indicated the reliability of the method for automatic and real-time inference of psychological states. This method provided a quantitative estimation of the workload levels and a bias-free evaluation approach. The high-average accuracy of 90% and cost effective requirement were the two important attributes of the proposed workload estimation system. New entropic features were proved to be more sensitive measures for quantifying time and frequency changes in EDA. The effectiveness of these measures was also compared with conventional tonic EDA measures, demonstrating the superiority of the proposed method in achieving accurate estimation of workload levels.

Scrutinizing the Emotional Nature of Intuitive Coherence Judgments.

Dual‐system models propose that cognitive processing can occur either intuitively or deliberately. Unlike deliberate decision strategies, intuitive ones are assumed to have an emotional component attached to the decision process. We tested if intuitive decisions are indeed accompanied by an emotional response while deliberate decisions are not. Specifically, we conducted a psychophysiological study in which participants were instructed to decide either intuitively or deliberately if three simultaneously presented words were semantically coherent or incoherent (triad task). The degree of emotionality of these two decision strategies (intuitive vs. deliberate) was compared using changes in electrodermal activity (EDA) and the reaction time (RT) effect of an affective priming paradigm as primary measurements. Based on a valence‐arousal model, our results revealed that intuitive and deliberate judgments do not differ as to their emotional valence but that they do differ in emotional arousal. Most notably, sympathetic activation during intuitive judgments was significantly lower compared to sympathetic activation during deliberate judgments. Our results reflect that a relaxed state of mind—manifested in low sympathetic activity—could underlie the holistic processing that is assumed to facilitate the proliferation of semantic associations during coherence judgments. This suggests that coherence judgments made under an (instructed) intuitive decision mode have a specific psychophysiological signature and that arousal is the differentiating component between intuitive and deliberate decision strategies. © 2016 The Authors Journal of Behavioral Decision Making Published by John Wiley & Sons Ltd.

Rorschach Performance Assessment System (R-PAS) and vulnerability to stress: A preliminary study on electrodermal activity during stress.

This study investigated the predictive validity of the ten Rorschach Performance Assessment System (R-PAS) variables from the Stress and Distress domain, by testing whether they predicted increased sympathetic reactivity to a mild, laboratory-induced stress, occurred one week after Rorschach administration. A relatively small student sample (N=52) contributed to this research: During a first meeting (T1) participants were administered the Rorschach task according to R-PAS guidelines; about one week later (T2) their electrodermal activity (EDA) was recorded during exposure to a mild laboratory stress-inducing task. Based on literature indicating that exposure to stress tends to increase physiological vulnerability/reactivity to stressful situations, we anticipated that Stress and Distress R-PAS variables measured at T1 would positively correlate with increased sympathetic reactivity to stress at T2, as indicated by greater EDA changes from baseline to stress and recovery. Results partially confirmed our hypotheses: (a) the mean of and (b) the majority of the Stress and Distress R-PAS variables were significantly correlated, in the expected direction, with medium and medium to large effect sizes.

Social stimuli increase physiological reactivity but not defensive responses.

Emotional reactions are crucial in survival because they provide approach and withdrawal behaviors. However, an unsolved question is whether the social content of the affective stimuli has a specific effect on emotional responses. We studied whether the social content of affective pictures influenced the defensive response and response mobilization. For this purpose, we recorded startle blink reflex (a defensive response) and skin conductance responses (ameasure of unspecific physiological reactivity or arousal) in 73 participants while they viewed a series of 81 pictures of varying affective valence and social content. Our results revealed that defense response, as indicated by increases in the magnitude of the startle blink reflex, was mainly dependent on threatening or unpleasant cues, but was unrelated to the social content of the pictures. The social content, however, had an influence on pleasant stimuli, provoking an increase in resource mobilization, as reflected by changes in electrodermal activity. Hence, the social content of the affective stimuli may increase the physiological arousal elicited by pleasant stimuli, and it appears to be unrelated to the defense reactivity provoked by unpleasant stimuli.

Recognition and Treatment of Nerve Agent Casualties: Evidence of Reduced Learner Engagement During Video-based Training.

Changes in electrodermal activity (EDA) correlate with arousal and stress during stimulating experiences. We hypothesized that associations exist between short-term performance gains and changes in EDA. A total of 187 combat medics were randomly assigned to simulation (S), live tissue (L), or video (V) based training in the recognition and treatment of nerve agent casualties. Change in EDA from baseline to training was quantified for tonic and phasic responses and was categorized as positive (>+10%), no change (±10%), or negative (<-10%). Cognitive and psychomotor skills assessments were applied before and after the baseline/training period to quantify short-term performance changes. Statistically significant differences in both EDA arousal measures between training modalities (p < 0.001 with L > S ∼ V) were observed. Notably, larger proportions of trainees experienced negative changes in tonic (67%) and phasic (21%) EDA measures in the V group when compared to the L and S groups. Regardless of training modality, negative tonic and phasic EDA responses were associated with lower psychomotor performance gains and this finding approached statistical significance (tonic: p = 0.056, phasic: p = 0.08). No significant differences were noted in pre- to post-training cognitive performance between EDA response categories. As quantified by EDA response to training, reduced arousal was associated with lower short-term psychomotor, but not cognitive, performance gains.

Vestibulo-spinal and vestibulo-ocular reflexes are modulated when standing with increased postural threat

We investigated how vestibulo-spinal reflexes (VSRs) and vestibulo-ocular reflexes (VORs) measured through vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) outcomes, respectively, are modulated during standing under conditions of increased postural threat. Twenty-five healthy young adults stood quietly at low (0.8 m from the ground) and high (3.2 m) surface height conditions in two experiments. For the first experiment (n = 25) VEMPs were recorded with surface EMG from inferior oblique (IO), sternocleidomastoid (SCM), trapezius (TRP), and soleus (SOL) muscles in response to 256 air-conducted short tone bursts (125 dB SPL, 500 Hz, 4 ms) delivered via headphones. A subset of subjects (n = 19) also received horizontal and vertical head thrusts (∼150°/s) at each height in a separate session, comparing eye and head velocities by using a vHIT system for calculating the functional VOR gains. VEMP amplitudes (IO, TRP, SOL) and horizontal and vertical vHIT gains all increased with high surface height conditions (P < 0.05). Changes in IO and SCM VEMP amplitudes as well as horizontal vHIT gains were correlated with changes in electrodermal activity (ρ = 0.44-0.59, P < 0.05). VEMP amplitude for the IO also positively correlated with fear (ρ = 0.43, P = 0.03). Threat-induced anxiety, fear, and arousal have significant effects on VSR and VOR gains that can be observed in both physiological and functional outcome measures. These findings provide support for a potential central modulation of the vestibular nucleus complex through excitatory inputs from neural centers involved in processing fear, anxiety, arousal, and vigilance.

Neural signatures of experimentally induced flow experiences identified in a typical fMRI block design with BOLD imaging.

Previously, experimentally induced flow experiences have been demonstrated with perfusion imaging during activation blocks of 3 min length to accommodate with the putatively slowly evolving "mood" characteristics of flow. Here, we used functional magnetic resonance imaging (fMRI) in a sample of 23 healthy, male participants to investigate flow in the context of a typical fMRI block design with block lengths as short as 30 s. To induce flow, demands of arithmetic tasks were automatically and continuously adjusted to the individual skill level. Compared against conditions of boredom and overload, experience of flow was evident from individuals' reported subjective experiences and changes in electrodermal activity. Neural activation was relatively increased during flow, particularly in the anterior insula, inferior frontal gyri, basal ganglia and midbrain. Relative activation decreases during flow were observed in medial prefrontal and posterior cingulate cortex, and in the medial temporal lobe including the amygdala. Present findings suggest that even in the context of comparably short activation blocks flow can be reliably experienced and is associated with changes in neural activation of brain regions previously described. Possible mechanisms of interacting brain regions are outlined, awaiting further investigation which should now be possible given the greater temporal resolution compared with previous perfusion imaging.

Eating ghosts: The underlying mechanisms of mood repair via interactive and noninteractive media.

Mood repair is a well-established function of media usage implying distraction from negative mood and the modification of unpleasant arousal states. Recent studies have found interactive media, in particular computer games, to be more effective in repairing mood than noninteractive media. It has been suggested that this is due to the higher task demand of interactive media distracting the players from negative feelings. Yet interactive media have also been found to increase arousal, which can also be seen as a cause for successful mood repair. It remains an open question which mechanism or to which degree both mechanisms-distraction and arousal regulation-account for mood repair via interactive media. The current study was designed to examine this so far unanswered question. We analyzed how effectively negative moods were regulated after a computer game, after a gameplay video, and without media consumption (control group). Mood repair, physiological arousal (positive change in electrodermal activity), and subjective arousal were assessed. Results confirmed that computer games led to a higher degree of mood repair and that this repair was a function of task demand as well as arousal characteristics. Results are discussed in terms of arousal regulation and intervention potential in interactive media.

Autonomic changes in psychogenic nonepileptic seizures: toward a potential diagnostic biomarker?

Disturbances of the autonomic nervous system (ANS) are common in neuropsychiatric disorders. Disease specific alterations of both sympathetic and parasympathetic activity can be assessed by heart rate variability (HRV), whereas electrodermal activity (EDA) can assess sympathetic activity. In posttraumatic stress disorder (PTSD), parasympathetic HRV parameters are typically decreased and EDA is increased, whereas in major depressive disorder (MDD) and dissociation, both parasympathetic and sympathetic markers are decreased. ANS abnormalities have also been identified in psychogenic nonepileptic seizures (PNES) by using HRV, indicating lower parasympathetic activity at baseline. In addition to reviewing the current literature on ANS abnormalities in PTSD, MDD, and disorders with prominent dissociation, including borderline personality disorder (BPD), this article also presents data from a pilot study on EDA in patients with PNES. Eleven patients with PNES, during an admission to our epilepsy monitoring unit (EMU), were compared with 9 with generalized tonic-clonic seizures (GTCS). The area under the EDA curve, the number of EDA responses lasting longer than 2 seconds, and the number of EDA surges during sleep (sympathetic sleep storms) were calculated on ictal and interictal days by an automated algorithm. EDA changes in PNES patients did not follow a systematic pattern of sympathetic hyperarousal (like EDA after GTCS) but were more variable. How specific PNES semiologies, and/or underlying neuropsychiatric disorders, may influence ictal and interictal EDA patterns, and lead to a novel diagnostic biomarker remains to be evaluated in future larger studies.

Real-time mobile detection of drug use with wearable biosensors: a pilot study.

While reliable detection of illicit drug use is paramount to the field of addiction, current methods involving self-report and urine drug screens have substantial limitations that hinder their utility. Wearable biosensors may fill a void by providing valuable objective data regarding the timing and contexts of drug use. This is a preliminary observational study of four emergency department patients receiving parenteral opioids and one individual using cocaine in a natural environment. A portable biosensor was placed on the inner wrist of each subject, to continuously measure electrodermal activity (EDA), skin temperature, and acceleration. Data were continuously recorded for at least 5 min prior to drug administration, during administration, and for at least 30 min afterward. Overall trends in biophysiometric parameters were assessed. Injection of opioids and cocaine use were associated with rises in EDA. Cocaine injection was also associated with a decrease in skin temperature. Opioid tolerance appeared to be associated with a blunted physiologic response as measured by the biosensor. Laterality may be an important factor, as magnitude of response varied between dominant and nondominant wrists in a single patient with bilateral wrist measurements. Changes in EDA and skin temperature are temporally associated with intravenous administration of opioids and cocaine; the intensity of response, however, may vary depending on history and extent of prior use.