The impact of extinction timing on pre-extinction arousal and subsequent return of fear.

Exposure-based therapy is effective in treating anxiety, but a return of fear in the form of relapse is common. Exposure is based on the extinction of Pavlovian fear conditioning. Both animal and human studies point to increased arousal during immediate compared to delayed extinction (>+24 h), which presumably impairs extinction learning and increases the subsequent return of fear. Impaired extinction learning under arousal might interfere with psychotherapeutic interventions. The aim of the present study was to investigate whether arousal before extinction differs between extinction groups and whether arousal before extinction predicts the return of fear in a later (retention) test. As a highlight, both the time between fear acquisition and extinction (immediate vs. delayed) and the time between extinction and test (early vs. late test) were systematically varied. We performed follow-up analyses on data from 103 young, healthy participants to test the above hypotheses. Subjective arousal ratings and physiological arousal measures of sympathetic and hypothalamic pituitary adrenal axis activation (tonic skin conductance and salivary cortisol) were collected. Increased pre-extinction arousal in the immediate extinction group was only confirmed for subjective arousal. In linear regression analyses, none of the arousal measures predicted a significant return of fear in the different experimental groups. Only when we aggregated across the two test groups, tonic skin conductance at the onset of extinction predicted the return of fear in skin conductance responses. The overall results provide little evidence that pre-extinction arousal affects subsequent extinction learning and memory. In terms of clinical relevance, there is no clear evidence that exposure could be improved by reducing subjective or physiological arousal.

Appetitive conditioning with pornographic stimuli elicits stronger activation in reward regions than monetary and gaming-related stimuli.

Appetitive conditioning plays an important role in the development and maintenance of pornography-use and gaming disorders. It is assumed that primary and secondary reinforcers are involved in these processes. Despite the common use of pornography and gaming in the general population appetitive conditioning processes in this context are still not well studied. This study aims to compare appetitive conditioning processes using primary (pornographic) and secondary (monetary and gaming-related) rewards as unconditioned stimuli (UCS) in the general population. Additionally, it investigates the conditioning processes with gaming-related stimuli as this type of UCS was not used in previous studies. Thirty-one subjects participated in a differential conditioning procedure in which four geometric symbols were paired with either pornographic, monetary, or gaming-related rewards or with nothing to become conditioned stimuli (CS + porn, CS + game, CS + money, and CS-) in an functional magnetic resonance imaging study. We observed elevated arousal and valence ratings as well as skin conductance responses for each CS+ condition compared to the CS-. On the neural level, we found activations during the presentation of the CS + porn in the bilateral nucleus accumbens, right medial orbitofrontal cortex, and the right ventral anterior cingulate cortex compared to the CS-, but no significant activations during CS + money and CS + game compared to the CS-. These results indicate that different processes emerge depending on whether primary and secondary rewards are presented separately or together in the same experimental paradigm. Additionally, monetary and gaming-related stimuli seem to have a lower appetitive value than pornographic rewards.

No evidence that arousal affects reactivated memories.

Memory for inherently neutral elements of emotional events is often enhanced on delayed tests - an effect that has been attributed to noradrenergic arousal. Reactivation of a memory is thought to return its corresponding neural ensemble to a state that is similar to when it was originally experienced. Therefore, we hypothesized that neutral elements of memories, too, can be enhanced through reactivation concurrent with heightened arousal. Participants (n = 94) visited the lab for three sessions. During the first session, they encoded 120 neutral memories consisting of an object presented in unique context images. In session two, the 80 objects were reactivated by presenting their corresponding context images, 40 of which were immediately followed by an arousal-inducing shock. Finally, recognition memory for all objects was tested. It was found that memory for reactivated objects was enhanced, but even though the shocks elicited elevations in arousal as indexed by skin conductance, there was no difference between memory of objects reactivated with and without heightened arousal. We thus conclude that arousal, when isolated from other cognitive and affective variables that might impact memory, has no enhancing effect on reactivated memories.

Decontextualized fear memories? Stronger conditioned fear responses during extinction learning and extinction recall in a safe context predict the development of long-term analog intrusions.

BACKGROUND: Difficulties in the context-dependent modulation of conditioned fear are known for posttraumatic stress disorder and may explain the occurrence of intrusive memories in safe contexts. The current study therefore investigated if reduced context-dependent modulation of conditioned fear and its underlying neural circuitry constitute risk factors for the development of analog intrusions in response to an experimental trauma. METHODS: Eighty-five healthy women participated in the trauma film paradigm to investigate the development of analog intrusions as well as explicit memory for an experimental trauma after one week and three months, respectively. Before, participants underwent a context-dependent fear conditioning paradigm during functional magnetic resonance imaging with fear acquisition in context A and extinction training in context B on a first day, as well as extinction recall in context B and fear renewal in a novel context C one day later. Skin conductance responses (SCRs) and blood oxygen level dependent responses were main outcome measures. RESULTS: In addition to stronger fear acquisition in context A, stronger conditioned fear responses in the safe context B, as indicated by stronger conditioned SCRs or stronger activation of fear expressing regions during extinction learning and recall, predicted the development of long-term analog intrusions. CONCLUSIONS: Stronger fear responses in safe and danger contexts were risk factors for the development of long-term analog intrusions and point to decontextualized fear memories and difficulties in the context-dependent modulation of conditioned fear. Altered fear conditioning processes and reduced storage of contextual information may cause the occurrence of fear independent of context.

Neural correlates of context-dependent extinction recall in social anxiety disorder: relevance of intrusions in response to aversive social experiences.

BACKGROUND: There are phenomenological similarities between social anxiety disorder (SAD) and posttraumatic stress disorder, such as a provoking aversive event, posttraumatic stress symptoms (e.g. intrusions) in response to these events and deficient (context-dependent) fear conditioning processes. This study investigated the neural correlates of context-dependent extinction recall and fear renewal in SAD, specifically in patients with intrusions in response to an etiologically relevant aversive social event. METHODS: During functional magnetic resonance imaging a two-day context-dependent fear conditioning paradigm was conducted in 54 patients with SAD and 54 healthy controls (HC). This included fear acquisition (context A) and extinction learning (context B) on one day, and extinction recall (context B) as well as fear renewal (contexts C and A) one day later. The main outcome measures were blood oxygen level-dependent responses in regions of interest and skin conductance responses. RESULTS: Patients with SAD showed reduced differential conditioned amygdala activation during extinction recall in the safe extinction context and during fear renewal in the acquisition context compared to HC. Patients with clinically relevant intrusions moreover exhibited hypoactivation of the ventromedial prefrontal cortex (vmPFC) during extinction learning, extinction recall, and fear renewal in a novel context, while amygdala activation more strongly decreased during extinction learning and increased during fear renewal in the acquisition context compared with patients without intrusions. CONCLUSIONS: Our study provides first evidence that intrusions in SAD are associated with similar deficits in context-dependent regulation of conditioned fear via the vmPFC as previously demonstrated in posttraumatic stress disorder.

Can I see it in the eyes? An investigation of freezing-like motion patterns in response to avoidable threat.

Freezing is one of the most extensively studied defensive behaviors in rodents. Both reduced body and gaze movements during anticipation of threat also occur in humans and have been discussed as translational indicators of freezing but their relationship remains unclear. We thus set out to elucidate body and eye movements and concomitant autonomic dynamics in anticipation of avoidable threat. Specifically, 50 participants viewed naturalistic pictures that were preceded by a colored fixation cross, signaling them whether to expect an inevitable (shock), no (safety), or a potential shock (flight) that could be avoided by a quick button press. Body sway, eye movements, the heart rate and skin conductance were recorded. We replicated previously described reductions in body sway, gaze dispersion, and the heart rate, and a skin conductance increase in flight trials. Stronger reductions in gaze but not in body sway predicted faster motor reactions on a trial-wise basis, highlighting their functional role in action preparation. We failed to find a trait-like relationship between body and gaze movements across participants, but their temporal profiles were positively related within individuals, suggesting that both metrics partly reflect the same construct. However, future research is desirable to assess these response patterns in naturalistic environments. A more ethological examination of different movement dynamics upon threat would not only warrant better comparability between rodent and human research but also help determine whether and how eye-tracking could be implemented as a proxy for fear-related movements in restricted brain imaging environments.

The interactive roles of narrative processing and emotion negativity/lability in relation to autonomic coordination.

Emotion regulation (ER) is a multifaceted construct, involving behavioral, cognitive, and physiological processes. Although autonomic coordination is theorized to play a crucial role in adaptive functioning, few studies have examined how different individual and contextual factors together may contribute to such coordination. This study examined the joint influences of narrative processing and emotional negativity/lability (N/L) traits on the coordination of the sympathetic and parasympathetic nervous systems in a sample of 112 children, ages 8-12 years (Mage = 10.15 years, SD = 1.33). Children completed a stress-induction task followed by an interview about the task. Children's trait-level N/L was assessed via parent-report on the Emotion Regulation Checklist. Narrative processing was assessed and coded based on children's narrative accounts of the event (i.e., causal coherence, overall emotional tone). Indexes of sympathetic (skin conductance response, SCR) and parasympathetic (respiratory sinus arrhythmia, RSA) functioning were derived from physiological data obtained during the interview. Results revealed that children's trait-level N/L and narrative processing of the stressful event interacted to predict the RSA-SCR correlation. Specifically, children who were high on either N/L or narrative causal coherence, but not both, demonstrated significant RSA-SCR correlation. Similarly, children with high N/L and negative-to-neutral narratives, as well as those with low N/L and neutral-to-positive narratives, exhibited significant RSA-SCR correlation. This work provides empirical evidence that narrative processing and trait N/L, together with RSA-SCR correlation, work in tandem to regulate emotional arousal.

Topographic mapping of the sensorimotor qualities of empathic reactivity: A psychophysiological study in people with spinal cord injuries.

The experience of empathy for pain is underpinned by sensorimotor and affective dimensions which, although interconnected, are at least in part behaviorally and neurally distinct. Spinal cord injuries (SCI) induce a massive, below-lesion level, sensorimotor body-brain disconnection. This condition may make it possible to test whether sensorimotor deprivation alters specific dimensions of empathic reactivity to observed pain. To explore this issue, we asked SCI people with paraplegia and healthy controls to observe videos of painful or neutral stimuli administered to a hand (intact) or a foot (deafferented). The stimuli were displayed by means of a virtual reality set-up and seen from a first person (1PP) or third person (3PP) visual perspective. A number of measures were recorded ranging from explicit behaviors like explicit verbal reports on the videos, to implicit measures of muscular activity (like EMG from the corrugator and zygomatic muscles that may represent a proxy of sensorimotor empathy) and of autonomic reactivity (like the electrodermal response and Respiratory Sinus Arrhythmia that may represent a general proxy of affective empathy). While no across group differences in explicit verbal reports about the pain stimuli were found, SCI people exhibited reduced facial muscle reactivity to the stimuli applied to the foot (but not the hand) seen from the 1PP. Tellingly, the corrugator activity correlated with SCI participants' neuropathic pain. There were no across group differences in autonomic reactivity suggesting that SCI lesions may affect sensorimotor dimensions connected to empathy for pain.

Exercise-induced central and peripheral sympathetic activity in a community-based group of epilepsy patients differ from healthy controls.

Ictal and interictal activity within the autonomic nervous system is characterized by a sympathetic overshoot in people with epilepsy. This autonomic dysfunction is assumed to be driven by alterations in the central autonomic network. In this study, exercise-induced changes of the interrelation of central and peripheral autonomic activity in patients with epilepsy was assessed. 21 patients with epilepsy (16 seizure-free), and 21 healthy matched controls performed an exhaustive bicycle ergometer test. Immediately before and after the exercise test, resting state electroencephalography measurements (Brain Products GmbH, 128-channel actiCHamp) of 5 min were carried out to investigate functional connectivity assessed by phase locking value in source space for whole brain, central autonomic network and visual network. Additionally, 1-lead ECG (Brain products GmbH) was performed to analyze parasympathetic (root mean square of successive differences (RMSSD) of the heart rate variability) and sympathetic activity (electrodermal activity (meanEDA)). MeanEDA increased (p < 0.001) and RMSSD decreased (p < 0.001) from pre to post-exercise in both groups. Correlation coefficients of meanEDA and central autonomic network functional connectivity differed significantly between the groups (p = 0.004) after exercise. Both patients with epilepsy and normal control subjects revealed the expected physiological peripheral autonomic responses to acute exhaustive exercise, but alterations of the correlation between central autonomic and peripheral sympathetic activity may indicate a different sympathetic reactivity after exercise in patients with epilepsy. The clinical relevance of this finding and its modulators (seizures, anti-seizure medication, etc.) still needs to be elucidated.

Neural correlates of immediate versus delayed extinction when simultaneously varying the time of the test in humans.

Anxiety disorders are effectively treated with exposure therapy based on the extinction of Pavlovian fear conditioning. Animal research indicates that both the timing of extinction and test are important factors to reduce the return of fear. However, empirical evidence in humans is incomplete and inconsistent. In this neuroimaging study, we, therefore, tested 103 young, healthy participants in a 2-factorial between-subjects design with the factors extinction group (immediate, delayed) and test group (+1 day and +7 days). Immediate extinction led to greater retention of fear memory at the beginning of extinction training indicated by increased skin conductance responses. A return of fear was observed in both extinction groups, with a trend toward a greater return of fear in immediate extinction. The return of fear was generally higher in groups with an early test. Neuroimaging results show successful cross-group fear acquisition and retention, as well as activation of the left nucleus accumbens during extinction training. Importantly, the delayed extinction group showed a larger bilateral nucleus accumbens activation during test. This nucleus accumbens finding is discussed in terms of salience, contingency, relief, and prediction error processing. It may imply that the delayed extinction group benefits more from the test as a new learning opportunity.

Validating the usefulness of Sudoscan in ATTRv: a single centre experience.

BACKGROUND: Variant transthyretin amyloidosis (ATTRv) can cause sensorimotor and autonomic neuropathy. Objective quantification of sudomotor function may be essential for early diagnosis and early initiation of treatment. The aim of this study is to evaluate the diagnostic value of the Sudoscan® in ATTRv. METHODS: Electrochemical skin conductance (ESC) was measured in V30M ATTRv patients, asymtomatic V30M carriers and healthy controls. Comparisons between the three groups were made using the Kruskal-Wallis test, and ROC curves were used to estimate the discriminatory power of ESC values between groups. RESULTS: ESC was measured in 52 ATTRv patients, 107 asymptomatic carriers and 40 healthy controls. ESC was significantly lower in ATTRv patients compared to asymptomatic carriers and healthy controls in both feet and hands; median values are as follows: 40 µS, 78 µS and 81 µS, respectively (p < 0.001), and 53 µS, 69 µS and 74 µS, respectively (p < 0.001). ESC in feet < 70.5 µS had a sensitivity of 89.7% and specificity of 84.6% to discriminate asymptomatic carriers from patients with ATTRv. CONCLUSION: The determination of ESC by Sudoscan® is a rapid, noninvasive and easily reproducible technique capable of discriminating patients with ATTRv from asymptomatic carriers and healthy controls with adequate sensitivity and specificity.

Correlation of non-invasive psycho-physiological and skin-physiological measures.

INTRODUCTION: Psychological stress alters epidermal barrier function. While intensive studies on the underlying mechanism have been performed in mice, human studies are limited. Non-invasive skin-physiology measures have not yet been directly linked to non-invasive psycho-physiological assessments. METHODS: Standard measures of (I) transepidermal water loss prior to and after experimental barrier perturbation via tape stripping, (II) skin surface pH, (III) electrodermal activity, and (IV) heart rate function were taken over a 24 h time period. To document perceived stress, a standardized stress self-assessment questionnaire, namely the Trierer Inventar zum chronischen Stress (TICS), was utilized. RESULTS: Twenty healthy, Caucasian (Fitzpatrick skin phototype I-II), female volunteers (21-32 years, mean age 27, SD = 3.67 years) were included in this study (random sample). Significant correlations were shown for 24 h delta transepidermal water loss changes, that is, barrier repair kinetics (sympathetic activity) and heart rate variability (parasympathetic activity). Further correlations were noted for electrodermal activity and skin surface pH. Perceived stress, as documented by the TICS questionnaire, did not correlate with psycho- and skin physiological parameters, respectively. CONCLUSION: The presented approaches may provide a basis for non-invasive objective research on the correlation between psychological stressors and epidermal barrier function.

Comparative analysis of electrodermal activity metrics and their association with child behavior in autism spectrum disorder.

Researchers are increasingly utilizing physiological data like electrodermal activity (EDA) to understand how stress "gets under the skin." Results of EDA studies in autistic children are mixed, with some suggesting autistic hyperarousal, others finding hypoarousal, and yet others detecting no difference compared to non-autistics. Some of this variability likely stems from the different techniques used to assess EDA. Therefore, the purpose of this study is to investigate and compare commonly used metrics of EDA (frequency of peaks, average amplitude of peaks, and standard deviation of skin conductance level) using two data processing programs (NeuroKit2 and Ledalab) and their link to observed child behavior. EDA data were collected using Empatica E4 wristbands from 60 autistic children and adolescents (5-18 years old) during a 7-min play interaction with their primary caregiver. The play interaction was coded for a range of child behaviors including mood, social responsiveness, dysregulation, and cooperation. Results indicate a strong correlation between NeuroKit2 and Ledalab and a weak correlation between metrics within each program. Furthermore, the frequency of peaks was associated with more positive child social behaviors, and the magnitude of peaks was associated with less adaptive child behaviors. Recommendations for replication and the need for generalizability of this research are given.

Post-Takeover Proficiency in Conditionally Automated Driving: Understanding Stabilization Time with Driving and Physiological Signals.

In the realm of conditionally automated driving, understanding the crucial transition phase after a takeover is paramount. This study delves into the concept of post-takeover stabilization by analyzing data recorded in two driving simulator experiments. By analyzing both driving and physiological signals, we investigate the time required for the driver to regain full control and adapt to the dynamic driving task following automation. Our findings show that the stabilization time varies between measured parameters. While the drivers achieved driving-related stabilization (winding, speed) in eight to ten seconds, physiological parameters (heart rate, phasic skin conductance) exhibited a prolonged response. By elucidating the temporal and cognitive dynamics underlying the stabilization process, our results pave the way for the development of more effective and user-friendly automated driving systems, ultimately enhancing safety and driving experience on the roads.

Measurements of Electrodermal Activity, Tissue Oxygen Saturation, and Visual Analog Scale for Different Cuff Pressures.

The quantification of comfort in binding parts, essential human-machine interfaces (HMI) for the functioning of rehabilitation robots, is necessary to reduce physical strain on the user despite great achievements in their structure and control. This study aims to investigate the physiological impacts of binding parts by measuring electrodermal activity (EDA) and tissue oxygen saturation (StO2). In Experiment 1, EDA was measured from 13 healthy subjects under three different pressure conditions (10, 20, and 30 kPa) for 1 min using a pneumatic cuff on the right thigh. In Experiment 2, EDA and StO2 were measured from 10 healthy subjects for 5 min. To analyze the correlation between EDA parameters and the decrease in StO2, a survey using the visual analog scale (VAS) was conducted to assess the level of discomfort at each pressure. The EDA signal was decomposed into phasic and tonic components, and the EDA parameters were extracted from these two components. RM ANOVA and a post hoc paired t-test were used to determine significant differences in parameters as the pressure increased. The results showed that EDA parameters and the decrease in StO2 significantly increased with the pressure increase. Among the extracted parameters, the decrease in StO2 and the mean SCL proved to be effective indicators. Such analysis outcomes would be highly beneficial for studies focusing on the comfort assessment of the binding parts of rehabilitation robots.

Human Activity Recognition Algorithm with Physiological and Inertial Signals Fusion: Photoplethysmography, Electrodermal Activity, and Accelerometry.

Inertial signals are the most widely used signals in human activity recognition (HAR) applications, and extensive research has been performed on developing HAR classifiers using accelerometer and gyroscope data. This study aimed to investigate the potential enhancement of HAR models through the fusion of biological signals with inertial signals. The classification of eight common low-, medium-, and high-intensity activities was assessed using machine learning (ML) algorithms, trained on accelerometer (ACC), blood volume pulse (BVP), and electrodermal activity (EDA) data obtained from a wrist-worn sensor. Two types of ML algorithms were employed: a random forest (RF) trained on features; and a pre-trained deep learning (DL) network (ResNet-18) trained on spectrogram images. Evaluation was conducted on both individual activities and more generalized activity groups, based on similar intensity. Results indicated that RF classifiers outperformed corresponding DL classifiers at both individual and grouped levels. However, the fusion of EDA and BVP signals with ACC data improved DL classifier performance compared to a baseline DL model with ACC-only data. The best performance was achieved by a classifier trained on a combination of ACC, EDA, and BVP images, yielding F1-scores of 69 and 87 for individual and grouped activity classifications, respectively. For DL models trained with additional biological signals, almost all individual activity classifications showed improvement (p-value < 0.05). In grouped activity classifications, DL model performance was enhanced for low- and medium-intensity activities. Exploring the classification of two specific activities, ascending/descending stairs and cycling, revealed significantly improved results using a DL model trained on combined ACC, BVP, and EDA spectrogram images (p-value < 0.05).

Affective cognition in response to infant stimuli in pregnant compared with non-pregnant women.

Physiological, neurocognitive, and psychological changes facilitates adaptation to motherhood. This cross-sectional study aimed to examine differences between pregnant and non-pregnant women in affective cognitive and psychophysiological responses to infant stimuli. We hypothesized that pregnant women would display (I) reduced negative emotional reactivity and perception of distressed infant stimuli, (II) increased attention toward infants compared to adults, and (III) greater psychophysiological response to infant distress. The sample comprised 22 pregnant women (22-38 weeks gestation) and 18 non-pregnant nulliparous women. Four computerized tasks were administered to measure affective cognitive processing of infant stimuli, while recording facial expressions, electrodermal activity, and eye gazes. Results indicated that pregnant women exhibited fewer negative facial expressions, reported less frustration when exposed to distressed infant cries, and showed greater attention to emotional infant faces compared to non-pregnant women, but the differences did not remain statistically significant after correction for multiple comparisons. No differences were observed in psychophysiological responses. The findings indicate a possible pregnancy-mediated effect regarding the cognitive processing of infant stimuli, potentially as preparation for motherhood. Future research with larger samples and longitudinal design is needed to understand the predictors, timing, and plasticity of cognitive changes during pregnancy.

Enhancing thermal comfort prediction in high-speed trains through machine learning and physiological signals integration.

Heating, Ventilation, and Air Conditioning (HVAC) systems in high-speed trains (HST) are responsible for consuming approximately 70% of non-operational energy sources, yet they frequently fail to ensure provide adequate thermal comfort for the majority of passengers. Recent advancements in portable wearable sensors have opened up new possibilities for real-time detection of occupant thermal comfort status and timely feedback to the HVAC system. However, since occupant thermal comfort is subjective and cannot be directly measured, it is generally inferred from thermal environment parameters or physiological signals of occupants within the HST compartment. This paper presents a field test conducted to assess the thermal comfort of occupants within HST compartments. Leveraging physiological signals, including skin temperature, galvanic skin reaction, heart rate, and ambient temperature, we propose a Predicted Thermal Comfort (PTC) model for HST cabin occupants and establish an intelligent regulation model for the HVAC system. Nine input factors, comprising physiological signals, individual physiological characteristics, compartment seating, and ambient temperature, were formulated for the PTS model. In order to obtain an efficient and accurate PTC prediction model for HST cabin occupants, we compared the accuracy of different subsets of features trained by Machine Learning (ML) models of Random Forest, Decision Tree, Vector Machine and K-neighbourhood. We divided all the predicted feature values into four subsets, and did hyperparameter optimisation for each ML model. The HST compartment occupant PTC prediction model trained by Random Forest model obtained 90.4% Accuracy (F1 macro = 0.889). Subsequent sensitivity analyses of the best predictive models were then performed using SHapley Additive explanation (SHAP) and data-based sensitivity analysis (DSA) methods. The development of a more accurate and operationally efficient thermal comfort prediction model for HST occupants allows for precise and detailed feedback to the HVAC system. Consequently, the HVAC system can make the most appropriate and effective air supply adjustments, leading to improved satisfaction rates for HST occupant thermal comfort and the avoidance of energy wastage caused by inaccurate and untimely predictive feedback.

Momentary physiological indices related to eating disorders: A systematic and methodological review.

Eating disorders (ED) are serious psychiatric illnesses, with no everyday support to intervene on the high rates of relapse. Understanding physiological indices that can be measured by wearable sensor technologies may provide new momentary interventions for individuals with ED. This systematic review, searching large databases, synthesises studies investigating peripheral physiological (PP) indices commonly included in wearable wristbands (heart rate [HR], heart rate variability [HRV], electrodermal activity [EDA], peripheral skin temperature [PST], and acceleration) in ED. Inclusion criteria included: (a) full peer-reviewed empirical articles in English; (b) human participants with active ED; and (c) containing one of five wearable physiological measures. Kmet risk of bias was assessed. Ninety-four studies were included (Anorexia nervosa [AN; N = 4418], bulimia nervosa [BN; N = 916], binge eating disorder [BED; N = 1604], other specified feeding and eating disorders [OSFED; N = 424], and transdiagnostic [N = 47]). Participants with AN displayed lower HR and EDA and higher HRV compared to healthy individuals. Those with BN showed higher HRV, and lower EDA and PST compared to healthy individuals. Other ED and Transdiagnostic samples showed mixed results. PP differences are indicated through various assessments in ED, which may suggest diagnostic associations, although more studies are needed to validate observed patterns. Results suggest important therapeutic potential for PP in ED, and larger studies including diverse participants and diagnostic groups are needed to fully uncover their role in ED.

Normal values of sudomotor function assessed by electrochemical skin conductance in African population.

BACKGROUND: Dysfunction of small nerve fibers remains a major public health concern. Subjects suspected of having small nerve fiber damage need to undergo reliable tests to confirm the diagnosis. Sudomotor function test is a reliable noninvasive exploration for detecting peripheral neuropathies. Nevertheless, the normal reference values derived from the sudomotor function test are not known in the African population. The objective of this study was therefore to describe the normal values of Electrochemical Skin Conductance (ESC) measured by the sudomotor function test in healthy African subjects. MATERIALS AND METHODS: Between December 1st, 2021 and May 31st, 2022, ESC was measured in 475 healthy subjects (median age: 42 [31-53] years, 46% men) using a sudomotor function test, in the hands and feet. Investigators proposed the examination and received participants' consent; demographic, anthropometric, biological, and clinical data were obtained before the test. Data on 475 healthy study participants who underwent sudomotor function testing was collected and analyzed. The sociodemographic (age, sex), anthropometric (weight, height, waist circumference, body mass index), diastolic blood pressure, systolic blood pressure, heart rate, and electrochemical skin conductances of the hands and feet were assessed. RESULTS: ESC values were statistically higher in men compared to women (right hand ESC: 70 [60-78] versus 63 [53-72], left hand ESC: 72 [61-80] versus 68 [57-75], right foot ESC: 77 [82-99] versus 72 [64-79], ESC left foot: 76 [68-82] versus 72 [62-78] respectively). ESC values were significantly inversely correlated with age (right hand ESC: r=-0.12, P=0.006; left hand ESC: r=-0.11, P=0.01; right foot ESC: r=-0.37, P<0.0001; ESC left foot: r=-0.38, P<0.0001). ESC values measured in feet were significantly inversely correlated with body mass index (right foot r=-0.22, P<0.0001; left foot r=-0.21, P<0.0001). CONCLUSION: This study reports normal reference values for ESCs according to age and gender in the healthy African population. Progressive decrease in ESC with aging is confirmed by our data. The value of ESC seems lower in the African population than in other reported ethnicities. This finding needs to be further explored in additional studies.