Higher Skin Conductance Responses Research Articles

Pupil size correlates with heart rate, skin conductance, pulse wave amplitude, and respiration responses during emotional conflict and valence processing.

Pupil size is a non-invasive index for autonomic arousal mediated by the locus coeruleus-norepinephrine (LC-NE) system. While pupil size and its derivative (velocity) are increasingly used as indicators of arousal, limited research has investigated the relationships between pupil size and other well-known autonomic responses. Here, we simultaneously recorded pupillometry, heart rate, skin conductance, pulse wave amplitude, and respiration signals during an emotional face-word Stroop task, in which task-evoked (phasic) pupil dilation correlates with LC-NE responsivity. We hypothesized that emotional conflict and valence would affect pupil and other autonomic responses, and trial-by-trial correlations between pupil and other autonomic responses would be observed during both tonic and phasic epochs. Larger pupil dilations, higher pupil size derivative, and lower heart rates were observed in the incongruent condition compared to the congruent condition. Additionally, following incongruent trials, the congruency effect was reduced, and arousal levels indexed by previous-trial pupil dilation were correlated with subsequent reaction times. Furthermore, linear mixed models revealed that larger pupil dilations correlated with higher heart rates, higher skin conductance responses, higher respiration amplitudes, and lower pulse wave amplitudes on a trial-by-trial basis. Similar effects were seen between positive and negative valence conditions. Moreover, tonic pupil size before stimulus presentation significantly correlated with all other tonic autonomic responses, whereas tonic pupil size derivative correlated with heart rates and skin conductance responses. These results demonstrate a trial-by-trial relationship between pupil dynamics and other autonomic responses, highlighting pupil size as an effective real-time index for autonomic arousal during emotional conflict and valence processing.

What a relief! The pleasure of threat avoidance.

Relief, a pleasurable experience, is often triggered by successful threat avoidance. Although relief is regarded as the positive reinforcer for avoidance behavior, its rewarding nature remains to be demonstrated. In our study, 50 participants responded to cues associated with different magnitudes of monetary values or electrical stimuli. Successful responses to those cues resulted in monetary gains (i.e., rewards) or omissions of electrical stimulation (i.e., relief), followed by a pleasantness rating scale. We also measured physiological arousal via skin conductance. As expected, we found that for reward and relief similarly, higher magnitudes elicited more successful responses, higher pleasantness ratings, and higher skin conductance responses. Moreover, differential reward/relief response patterns predicted later choices between reward and relief cues. These findings indicate that relief induced by threat omissions is functionally equivalent to receiving a reward, confirming that relief is a positive reinforcer for threat avoidance behaviors, which provides a new theoretical perspective on the learning process of active threat avoidance. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Learning bias predicts fear acquisition under stress but not cognitive flexibility

Individuals differ in their ability to learn from reinforcement and in avoiding punishment, which can be measured by the Probabilistic Selection Task (PST). Recently, some studies have demonstrated that this learning bias is regulated by the dopaminergic system, and that stress can differentially affect the use of positive (i.e., reinforcement) and negative (i.e., avoiding punishment) feedback. The current two studies examined whether performance on the PST can predict measures of goal-directed behaviour as assessed by a cognitive flexibility task (Wisconsin Card Sorting Test) and the acquisition of fear responses, when individuals are exposed to a stressor (Socially Evaluated Cold Pressor Test). A total of 26 and 59 healthy participants completed Experiments I and II, respectively. In those who were best at learning from reinforcement, stress increased the processing (i.e., higher skin conductance responses) of non-threatening stimuli during fear acquisition compared to the non-stressful condition, which was not recapitulated in those who were best at avoiding punishment. Additionally, PST performance did not interact with stress to modulate cognitive flexibility, although stress negatively impaired this domain, consistent with previous findings. Furthermore, independent of stress, both positive and negative learning biases were correlated with cognitive flexibility errors. Our results demonstrate that the PST has predictive value for better understanding the determinants of reinforcement and avoidance learning.

Differing associations of depersonalization with physiological response during rest and breath-focused mindfulness in a trauma-exposed female population

BackgroundDissociative and posttraumatic stress disorder (PTSD) symptoms are commonly co-occurring responses to psychological trauma. Yet, these two groups of symptoms appear to be related to diverging patterns of physiological response. To date, few studies have examined how specific dissociative symptoms, namely, depersonalization and derealization, relate to skin conductance response (SCR), a marker of autonomic function, within the context of PTSD symptoms. We examined associations among depersonalization, derealization, and SCR during two conditions – resting control and breath-focused mindfulness – in the context of current PTSD symptoms. MethodsSixty-eight trauma-exposed women (82.4% Black; Mage = 42.5, SDage = 12.1) were recruited from the community for a breath-focused mindfulness study. SCR data were collected during alternating resting control and breath-focused mindfulness conditions. Moderation analyses were conducted to examine relations among dissociative symptoms, SCR, and PTSD for these different conditions. ResultsModeration analyses revealed that depersonalization was linked to lower SCR during resting control, B = 0.0005, SE = 0.0002, p = .006, in participants low-to-moderate PTSD symptoms; however, depersonalization was associated with higher SCR during breath-focused mindfulness, B = −0.0006, SE = 0.0003, p = .029, in individuals with similar levels of PTSD symptoms. No significant interaction between derealization and PTSD symptoms on SCR was observed. ConclusionsDepersonalization symptoms may associate with physiological withdrawal during rest, but greater physiological arousal during effortful emotion regulation in individuals with low-to moderate levels of PTSD, which has significant implications for barriers to treatment engagement as well as treatment selection in this population.

Context effects, skin conductance responses and personality traits – Influencing variables on risk-taking within a modified version of the balloon analog risk task

When individuals take risks, they must weigh potential costs and benefits associated with a decision. Differences in risk-taking appear to be influenced by contextual, and inter-individual factors. However, it is still ambiguous to what extent these characteristics jointly influence risk-taking. We investigated how risk-taking varies as function of context effects, incentives, skin conductance responses (SCR), and personality traits such as impulsivity and sensitivity to reward and punishment. Sixty-eight healthy participants conducted a modified version of the Balloon Analogue Risk Task (BART) composed of a gain-framed (G-BART) and loss-framed (L-BART) context with each a low and a high outcome magnitude condition. While the goal in G-BART was to maximize gains, the goal in L-BART was to minimize losses. In both versions, participants can potentially accumulate the same amounts. We conducted trial-by-trial mixed model analyses to account for within- and between-participant effects. Participants showed greater risk-taking when playing L-BART than G-BART; more risk-taking was observed in the high compared to the low outcome magnitude condition. Furthermore, higher SCR were associated with less risk-taking. Lower impulsivity was related to a greater difference in risk-taking in both contexts, with greater risk-taking in L-BART. Likewise, sensitivity to reward was associated with a greater difference in risk-taking in both contexts, with greater risk-taking in G-BART. Finally, greater sensitivity to punishment was related to risk-taking among participants describing themselves as sensitive to rewards. Results support a multidimensional state-trait model of risk-taking suggesting that risk-taking is favored by loss-aversion along with incentives, psychophysiological arousal, and personality traits.

Deep brain stimulation of the subgenual cingulum and uncinate fasciculus for the treatment of posttraumatic stress disorder.

Deep brain stimulation (DBS) has been investigated for neuropsychiatric disorders. In this phase 1 trial, we treated four posttraumatic stress disorder (PTSD) patients with DBS delivered to the subgenual cingulum and the uncinate fasciculus. In addition to validated clinical scales, patients underwent neuroimaging studies and psychophysiological assessments of fear conditioning, extinction, and recall. We show that the procedure is safe and potentially effective (55% reduction in Clinical Administered PTSD Scale scores). Posttreatment imaging data revealed metabolic activity changes in PTSD neurocircuits. During psychophysiological assessments, patients with PTSD had higher skin conductance responses when tested for recall compared to healthy controls. After DBS, this objectively measured variable was significantly reduced. Last, we found that a ratio between recall of extinguished and nonextinguished conditioned responses had a strong correlation with clinical outcome. As this variable was recorded at baseline, it may comprise a potential biomarker of treatment response.

Threat reversal learning and avoidance habits in generalised anxiety disorder

Avoidance and heightened responses to perceived threats are key features of anxiety disorders. These disorders are characterised by inflexibility in dynamically updating behavioural and physiological responses to aversively conditioned cues or environmental contexts which are no longer objectively threatening, often manifesting in perseverative avoidance. However, less is known about how anxiety disorders might differ in adjusting to threat and safety shifts in the environment or how idiosyncratic avoidance responses are learned and persist. Twenty-eight patients with generalised anxiety disorder (GAD), without DSM co-morbidities, and 27 matched healthy controls were administered two previously established paradigms: Pavlovian threat reversal and shock avoidance habits through overtraining (assessed following devaluation with measures of perseverative responding). For both tasks we used subjective report scales and skin conductance responses (SCR). In the Pavlovian threat reversal task, patients with GAD showed a significantly overall higher SCR as well as a reduced differential SCR response compared to controls in the early but not late reversal phase. During the test of habitual avoidance responding, GAD patients did not differ from controls in task performance, habitual active avoidance responses during devaluation, or corresponding SCR during trials, but showed a trend toward more abstract confirmatory subjective justifications for continued avoidance following the task. GAD patients exhibited significantly greater skin conductance responses to signals of threat than controls, but did not exhibit the major deficits in reversal and safety signal learning shown previously by patients with OCD. Moreover, this patient group, again unlike OCD patients, did not show evidence of altered active avoidance learning or enhanced instrumental avoidance habits. Overall, these findings indicate no deficits in instrumental active avoidance or persistent avoidance habits, despite enhanced responses to Pavlovian threat cues in GAD. They suggest that GAD is characterised by passive, and not excessively rigid, avoidance styles.

Sex film viewing, but not hypersexual concerns, are associated with more sexual arousal in anticipation of an intimate partner experience.

Hypersexual behaviours could reflect psychopathology, in part, because they impair interactions with intimate partners. Hypersexual concerns were measured as: (1) concern about inability to control one's own sexual behaviours; and (2) sexual films viewed. The outcome, sexual arousal, was measured using two indicators: (1) self-reported sexual arousal (before/after); and (2) skin conductance response from the person stimulated (continuously). Two-hundred and fifty participants completed Orgasmic Meditation (OM), a coupled, structured, 15-min manual-genital stroking. Reported difficulty controlling their own sexual behaviours was not related to sexual arousal reports. Participants who viewed more sexual films reported more sexual arousal before starting OM than participants who viewed less sexual films. Strokers who viewed more sexual films were associated with a higher skin conductance response in the stroked partner. Despite statistical power and pre-registration, hypersexual concerns did not predict sexual responses with a partner. Sex film viewing may increase sexual responsiveness in individuals and their partners.

Schizotypal personality traits and the social learning of fear

Schizotypy can be defined as a combination of traits qualitatively similar to those found in schizophrenia, but milder in their expression, that can be found in clinical and non-clinical populations. In this research, we explore, to our knowledge, for the first time, whether schizotypal personality traits may affect the acquisition of conditioned fear by social means only. Apart from being an essential capacity to ensure learning in safe environments, social fear learning shares important characteristics with direct fear acquisition, which also makes it a great candidate for developing successful extinction procedures. Undergraduate students (n = 72) performed a task of social fear learning. In this task, participants watched a video of a person that simulated to receive electric shocks (unconditioned stimulus; US) paired with a coloured square (conditioned stimulus plus; CS+), while another coloured square was never paired (conditioned stimulus minus; CS−) with the shock. After that, they were presented with a similar sequence of coloured screens. Their Skin Conductance Responses (SCRs) were registered during the whole process. Once they finished, they completed the Schizotypal Personality Questionnaire (SPQ). Our results revealed that participants with a low score in the Cognitive-Perceptual factor of the SPQ exhibited higher SCRs when they saw the US than when they saw the CS− (all ps < 0.01) during the learning phase. Nevertheless, those with higher scores did not present any difference in their SCRs toward both stimuli (all ps > 0.05), a pattern that has been similarly found in schizophrenia. During the final trials of the test phase, participants with the highest scores in the Disorganized factor were the only ones that maintained a higher SCR towards the CS+ than towards the CS− (p = 0.006), which could be associated with an impairment in their extinction processes.

Exposure to acute stress affects the retrieval of out-group related bias in healthy men

Individuals have a tendency to show enhanced vigilance to groups of which they themselves are not a member. Stress can up-regulate hypervigilance towards threatening stimuli and was shown to promote the reinstatement of out-group related biases in a previous study conducted in women only. The current study examines how exposure to acute stress affects the retrieval of out-group related extinction biases in male participants. Results showed that men exerted a specific out-group related bias at the beginning of extinction training indexed by higher skin conductance responses (SCRs) towards out-group faces, while stress led to a return of this extinguished out-group bias. Specifically, the stress group showed higher SCRs towards out-group faces during retrieval compared to the control group and the bias index was negatively related to post-stress cardiovascular recovery. These results indicate the important interaction between stress and intergroup bias in fear conditioning, along with a potential modulation of sex.

High vagal tone and rapid extinction learning as potential transdiagnostic protective factors following childhood violence exposure.

Childhood exposure to violence is strongly associated with psychopathology. High resting respiratory sinus arrhythmia (RSA) is associated with lower levels of psychopathology in children exposed to violence. High RSA may help to protect against psychopathology by facilitating fear extinction learning, allowing more flexible autonomic responses to learned threat and safety cues. In this study, 165 youth (79 female, aged 9-17; 86 exposed to violence) completed assessments of violence exposure, RSA, and psychopathology, and a fear extinction learning task; 134 participants returned and completed psychopathology assessments 2 years later. Resting RSA moderated the longitudinal association of violence exposure with post-traumatic stress disorder (PTSD) symptoms and externalizing psychopathology, such that the association was weaker among youths with higher RSA. Higher skin conductance responses (SCR) during extinction learning to the threat cue (CS+) was associated with higher internalizing symptoms at follow-up and greater SCR to the safety cue (CS-) was associated with higher PTSD, internalizing, and externalizing symptoms, as well as the p-factor, controlling for baseline symptoms. Findings suggest that higher RSA may protect against emergence of psychopathology among children exposed to violence. Moreover, difficulty extinguishing learned threat responses and elevated autonomic responses to safety cues may be associated with risk for future psychopathology.

BDNF genotype Val66Met interacts with acute plasma BDNF levels to predict fear extinction and recall

Brain-derived neurotropic factor (BDNF) is a potent regulator of memory processes and is believed to influence the consolidation of fear extinction memories. No previous human study has tested the effect of unstimulated BDNF on fear extinction recall, and no study has tested the association between plasma BDNF levels and psychophysiological responding during an extinction paradigm. We tested the association between fear responses during a 2-day differential conditioning, extinction and extinction recall paradigm and Val66Met genotype in a group of healthy participants (N = 191). There were no group differences during habituation or acquisition. Met allele carriers compared to Val homozygotes displayed higher responses to the CS + compared to the CS- during extinction learning and had higher responding to both the CS+ and CS- during extinction recall. Plasma levels of BDNF protein that were collected in a sub-sample of the group (n = 56) moderated the effect of Met allele presence, such that lower BDNF level was associated with higher skin conductance response in the Met but not Val group to the CS+ during extinction learning and to both the CS+ and CS- during extinction recall. The current results extend previous observations of a Val66Met effect during fear extinction learning to extinction recall and show for the first time that these effects are moderated by plasma BDNF level.

Playing Tetris Lets You Rate Odors as Less Intense.

Overweight and obesity are considered a huge problem in modern societies. Previous studies have shown that people who are regularly distracted by playing videogames or watching TV while eating are more likely to be overweight and that the number of people that are gaming worldwide is rising. Further, it has been established that both, watching TV or playing video games lead to an increased snack intake and a lower rating of perceived taste intensity. Since flavor perception is accomplished not only by the sense of taste but also the sense of smell, we investigated the influence of cognitive load created by playing a video game on odor intensity perception. The participants played a low or high difficulty version of Tetris while presented with odors of food and non-food items. A higher skin conductance response (SCR) along with a decrease in task performance verified that the higher difficulty level leads to a higher cognitive load. Our behavioral data indicates a significant decrease in intensity estimates of food odors and non-food odors during the high compared to low cognitive load condition. We conclude that odor intensity estimation is influenced by real-life cognitive tasks which might in turn lead to overeating while distracted.

The physiological correlates of interpersonal space

Interpersonal space (IPS) is the area around the body that individuals maintain between themselves and others during social interactions. When others violate our IPS, feeling of discomfort rise up, urging us to move farther away and reinstate an appropriate interpersonal distance. Previous studies showed that when individuals are exposed to closeness of an unknown person (a confederate), the skin conductance response (SCR) increases. However, if the SCR is modulated according to participant’s preferred IPS is still an open question. To test this hypothesis, we recorded the SCR in healthy participants when a confederate stood in front of them at various distances simulating either an approach or withdrawal movement (Experiment 1). Then, the comfort-distance task was adopted to measure IPS: participants stop the confederate, who moved either toward or away from them, when they felt comfortable with other’s proximity (Experiment 2). We found higher SCR when the confederate stood closer to participants simulating an IPS intrusion, compared to when the confederate moved farther away. Crucially, we provide the first evidence that SCR, acting as a warning signal, contributes to interpersonal distance preference suggesting a functional link between behavioral components of IPS regulation and the underlying physiological processes.

Continuity in intuition and insight: from real to naturalistic virtual environment

Intuition and insight can be deployed on the same continuum. Intuition is the unconscious ability to create links between information; insight is a process by which a sudden comprehension and resolution of a situation arises (i.e. euréka). In the present study, real and virtual environments were used to trigger intuition and insight. The study hypothesised that immersion in real primed environments would facilitate the emergence of intuition and insight in a virtual environment. Forty nine healthy participants were randomly assigned to two groups: “primed” and “non primed.” “Primed” participants were immersed in a real environment with olfactory and visual cues; “non primed” participants did not receive any cues. All participants were exposed to a 3D naturalistic virtual environment which represented a district in Paris via a Head Mounted Display (HMD). Locations presented in the virtual scene (i.e. café places) were related to both olfactory and visual primes (i.e. café) and were based on the continuity between real and virtual environments. Once immersed in the virtual environment, all participants were instructed to use their intuition to envision the selected locations during which Skin Conductance Responses (SCRs) and verbal declarations were recorded. When initiation (a) and immersion (b) phases in the virtual environment were considered, “primed” participants had higher SCRs during the immersion phase than the initiation phase in the virtual environment. They showed higher SRCs during the first part of the virtual immersion than “non primed” participants. During the phenomenological interview, “primed” participants reported a higher number of correct intuitive answers than “non primed” participants. Moreover, “primed” participants “with” insight had higher SCRs during real environment immersion than “primed” participants “without” insight. The findings are consistent with the idea that intuitive decisions in various tasks are based on the activation of pre-existing knowledge, which is unconsciously retrieved, but nevertheless can elicit an intuitive impression of coherence and can generate insight.

Comparing neural correlates of conditioned inhibition between children with and without anxiety disorders – A preliminary study

Cognitive-behavioral therapy (CBT), a first-line treatment for pediatric anxiety disorders, is based on principles of threat learning and extinction. However, CBT does not work sufficiently for up to 40% of clinically anxious youth. The neural and behavioral correlates of conditioned inhibition might provide promising targets for attempts to improve CBT response. During conditioned inhibition, threat and safety cues appear together, forming a safety compound. Here, we test whether this safety compound elicits a reduced fear response compared to pairing the threat cue with a novel cue (novel compound). The current pilot study compares behavioral, physiological, and neural correlates of conditioned inhibition between children with (n = 17, Mage = 13.09, SDage = 3.05) and without (n = 18, Mage = 14.49, SDage = 2.38) anxiety disorders. Behavioral and physiological measures did not differ between children with and without anxiety disorders during fear acquisition. During testing, children with anxiety disorders showed overall higher skin conductance response and expected to hear the aversive sound following the novel compound more often than children without anxiety disorders. Children with anxiety disorders showed more activity in the right ventromedial prefrontal cortex (vmPFC) to the safety versus novel compound. Children without anxiety disorders showed the opposite pattern – more right vmPFC activity to the novel versus safety compound (F(1,31) = 5.40, p = 0.03). No group differences manifested within the amygdala, dorsal anterior cingulate cortex, or hippocampus. These pilot findings suggest a feasible approach for examining conditioned inhibition in pediatric anxiety disorders. If replicated in larger samples, findings may implicate perturbed conditioned inhibition in pediatric anxiety disorders and provide targets for CBT.

Bad Choices Make Good Stories: The Impaired Decision-Making Process and Skin Conductance Response in Subjects With Smartphone Addiction.

Introduction: Smartphone Addiction (SA) has caused negative consequences and functional impairments in college students, such as reduction of academic performance and impairment in sleep quality. Studies have shown that individuals with chemical and behavioral dependencies have a bias in decision-making process, which leads to short-term advantageous choices even if they cause long-term harm. This bias in decision-making process is accompanied by a change in somatic markers and is associated with the development and maintenance of addictive behavior. The decision-making process and the measurement of physiological parameters have not yet been analyzed in SA. The neuropsychological and physiological characterization of the SA can contribute to its approach with the other dependency syndromes and to its recognition as a disease.Objective: we aimed to evaluate the decision-making process under risk and under ambiguity in individuals with SA and to measure the physiological parameters that accompany this process.Method: We compared the performance in the Iowa Gambling Task (IGT), Game of Dice Task (GDT) and skin conductance response (SCR) between 50 individuals with SA and 50 controls.Results: Smartphone dependents presented a profile of impairment in decision-making under ambiguity, without impairment in decision-making under risk. They demonstrated lower SCR before disadvantageous choices, higher SCR after rewards and lower SCR after punishments during decision-making, which suggests difficulty in recognizing disadvantageous alternatives, high sensitivity to rewards, and low sensitivity to punishments.Conclusion: The impairment in the decision-making process in smartphone dependents is similar to that found in other chemical and behavioral addictions, such as alcohol addiction, gambling disorders and pathological buy. The impairment in decision under ambiguity with preservation of decision under risk may reflect dysfunction of implicit emotional processes without dysfunction of explicit cognitive process. This profile can contribute to the recognition of SA as a behavioral dependence and to guide specific preventive and therapeutic strategies.

Progressively analogous evidence of covert face recognition from functional magnetic resonance imaging and skin conductance responses studies involving a patient with dissociative amnesia.

This is a case study involving a female patient (NN) with complete loss of autobiographical memory and identity despite normal neurological assessment. To test the hypothesis that patients with dissociative amnesia (DA) possess the ability to covertly process facial identities they are unaware of, we conducted functional magnetic resonance imaging (fMRI) and assessed skin conductance responses (SCR) to (a) strangers, (b) celebrities, and (c) familiar faces not seen since the onset of DA. We also performed associative face-name memory tasks to test the patient's ability to learn and recall newly learned face-name pairs. Although NN did not recognize any of the faces of her friends and relatives, their images triggered a stronger involvement of the left fusiform gyrus, the bilateral hippocampus/amygdala region, the orbitofrontal cortex, the middle temporal regions, and the precuneus, along with higher SCR. During recollection of previously learned face-name pairs, NN (compared to healthy controls) demonstrated a weaker involvement of the hippocampus. Our findings suggest that, in DA, specific arousal systems remain capable of being activated by familiar faces outside of conscious awareness. The decreased activation observed in the hippocampus demonstrates that the functioning of memory-sensitive regions may be impaired by trauma.

Modulation of Physiological Responses as Indices of Attentional Bias in Dysphoria

The experimental results on attentional bias in depression have been contradictory. Research on physiological correlates that validate attentional bias have been scarce. The aim of the present study was to evaluate physiological responses associated with attentional bias in dysphoria. Heart rate and the galvanic skin response were recorded in 30 dysphoric individuals and 30 nondysphoric individuals while they performed an emotional Stroop task. Dysphoric individuals exhibited attentional bias and heart rate deceleration in response to unpleasant words. Nondysphoric individuals exhibited attentional bias toward pleasant words, accompanied by a higher skin conductance response. These results suggest that heart rate deceleration in response to unpleasant words correlated with attentional bias in dysphoric individuals.

Mobile assessment of heightened skin conductance in posttraumatic stress disorder

Increased psychophysiological reactivity is a hallmark intermediate phenotype of posttraumatic stress disorder (PTSD). Individuals with PTSD exhibit greater skin conductance (SC) responses to trauma scripts than trauma survivors without PTSD. However, trauma scripts require time for development and cannot be easily used in a single visit. Thus, there is a need for a low-cost, easy-to-use, SC recording protocol for PTSD assessment. Using a mobile device (eSense) connected to a portable tablet computer, we assessed SC reactivity to a standard trauma interview (STI) in 63 participants recruited from Grady Memorial Hospital in Atlanta, GA, approximately 1 year after trauma exposure. SC response (SCR) was calculated by subtracting the SC level (SCL) at the end of the baseline recording from the maximum SCL during the STI. SCL was significantly higher during the STI compared to baseline (P < .001), and individuals with PTSD showed significantly greater SCR than individuals without PTSD (P = .006). Logistic regression using SCR with PTSD diagnosis as the outcome showed an odds ratio of 1.76 (95% CI: 1.11-2.78). Lastly, higher SCR during the STI was also significantly associated with PTSD symptom total score controlling for demographics and trauma severity (b = 0.42, P = .001). The current study demonstrated feasibility of the use of a mobile device for assessing psychophysiological reactivity in those with PTSD. The use of this low-cost, easy-to-use mobile device to collect objective physiological data in concert with a STI can be easily disseminated in clinical and research settings.