Interoception and stress in patients with Functional Neurological Symptom Disorder

Probing the functional magnetic resonance imaging response to psilocybin in functional neurological disorder (PsiFUND): study protocol

Background

Functional neurological disorder (FND) is a common cause of neurological symptoms including seizures and movement disorders. It can be debilitating, is associated with high health and social care costs, and can have a poor prognosis. Functional magnetic resonance imaging (fMRI) has suggested FND is a multi-network disorder. Converging evidence suggests that other mechanisms including dissociation, interoception, and motor agency may be abnormal in people with FND. Psychedelics are currently under investigation for numerous neuropsychiatric disorders and have been shown to disrupt functional brain networks. Administering psychedelics to people with FND will help us to probe mechanistic theories of the disorder.

Protocol

In this open-label neuroimaging study, we will administer 25mg oral psilocybin with psychological support to people with chronic FND (target n = 24). Participants will undergo resting-state and task-based (Libet's clock, a measure of motor agency) fMRI sequences which will be compared in a pre-post manner. Additional mechanistic outcomes including measures of interoception (heartbeat tracking task), somatisation, illness perceptions, suggestibility, and dissociation will be collected. Data on expectancy, preparedness, and subjective experience of the psychedelic experience will also be gathered. Participants will be followed up for three months following psilocybin administration. fMRI changes in networks will be analysed using seed-based approaches, and additional exploratory analysis of resting-state imaging will take place.

Discussion

The study will help us to probe the mechanisms thought to potentially underpin FND. As the first modern study of psychedelics in FND, it will also help us to understand whether psychedelic administration alongside psychological support might be safe and feasible in this patient population.

Functional movement disorder is associated with abnormal interoceptive brain activity: a task-based functional MRI study

Background

Aberrant interoceptive processing has been hypothesized to contribute to the pathophysiology of functional neurological disorder, although findings have been inconsistent. Here, we utilized functional magnetic resonance imaging (fMRI) to examine neural correlates of interoceptive attention - the conscious focus and awareness of bodily sensations - in functional movement disorder (FMD).

Methods

We used voxelwise analyses to compare blood oxygenation level-dependent responses between 13 adults with hyperkinetic FMD and 13 healthy controls (HCs) during a task requiring attention to different bodily sensations and to an exteroceptive stimulus. Additionally, we examined between-group differences in self-reported measures of interoception and evaluated their relationship with neural activity.

Results

Interoceptive conditions (heartbeat, stomach and 'body', indicating sensations from the body part or limb affected in FMD participants) activated a network involving the precuneus, the posterior cingulate cortex (PCC) and caudate nucleus (CN) bilaterally, and the right anterior insula (aINS) (p <0.05, corrected). Group differences in brain activity were mainly driven by processing of disease-related interoceptive signals, which in the FMD group was associated with a broader neural activation than monitoring gastric interoception, while no group differences were detected during cardiac interoception. Differences based on interoceptive focus (body vs heartbeat and stomach) between FMD subjects and HCs were found in PCC, CN, angular gyrus, thalamus, and in the mid-insula (p <0.05, corrected).

Conclusions

This is, to our knowledge, the first study showing that FMD is associated with abnormal interoceptive processing in regions involved in monitoring body state, attentional focus, and homeostatic inference.

Trajectories of Change, Illness Understanding, and Parental Worries in Children and Adolescents Undergoing Internet-Delivered Cognitive-Behavioral Therapy for Functional Abdominal Pain Disorders: Protocol for a Single-Case Design and Explorative Pilot Study

BACKGROUND

Functional abdominal pain disorders (FAPDs) are common in young people and are characterized by persistent or recurrent abdominal symptoms without apparent structural or biochemical abnormalities. FAPDs are associated with diminished quality of life, school absence, increased health care use, and comorbid anxiety and depression. Exposure-based internet-delivered cognitive behavioral therapy (ICBT) has demonstrated efficacy in alleviating abdominal symptoms and improving quality of life. However, a deeper understanding of effect mechanisms and identification of possible additional treatment targets could refine treatment.

OBJECTIVE

This protocol paper aims to describe a study focusing on children and adolescents undergoing ICBT for FAPDs, aiming to further investigate the underlying mechanisms of effect.

METHODS

Children (8-12 years), adolescents (13-17 years) with FAPDs, and their respective parents will be included for 10 weeks for ICBT. First, detailed trajectories of effect are examined through a randomized single-case design study involving 6 children and 6 adolescents (substudy 1). Following this, an open-ended explorative pilot study with 30 children and 30 adolescents explores potential illness-related cognitive biases and interoceptive accuracy before and after treatment (substudy 2). Finally, spanning across these 2 substudies, including all parents from substudies 1 and 2, we will assess parental distress and illness worries before and after treatment, and how these factors impact the treatment adherence and outcomes of the child or adolescent (substudy 3).

RESULTS

Recruitment of participants began in June 2022 and is finalized for substudy 1 and ongoing for substudies 2 and 3. Recruitment is expected to be completed by January 2025, with final data collection during April 2025.

CONCLUSIONS

The findings have the potential to contribute to the ongoing improvement of specialized psychological treatment for FAPDs in young people.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05237882; https://clinicaltrials.gov/study/NCT05237882; ClinicalTrials.gov NCT05486585; https://clinicaltrials.gov/study/NCT05486585; OSF Registries osf.io/c49k7; https://osf.io/c49k7.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/58563.

Functional Neurological Disorder and Autism Spectrum Disorder: A Complex and Potentially Significant Relationship

INTRODUCTION

Functional neurological disorder (FND) and autism spectrum disorder (ASD) are two complex neuropsychiatric conditions that have been historically classified within psychiatric domains, resulting in a lack of extensive research, insufficient clinical recognition, and persistent societal stigma. In recent years, there has been an increasing recognition among professionals and affected individuals of their possible overlap. This review explores the potential clinical and mechanistic overlap between FND and ASD, with particular attention to shared symptoms across sensory, motor, and psychiatric domains.

METHODS

We conducted a narrative analysis utilizing the PubMed, CINAHL, MEDLINE, and ScienceDirect databases from inception to June 2024. The search employed specific MeSH terms related to ASD and FND. Given the limited data availability, we included all relevant articles that explored the potential connections between FND and ASD, focusing on established findings and theoretical hypotheses areas.

RESULTS

Scientific evidence indicates that FND and ASD may co-occur more frequently than previously acknowledged and with notable overlaps in their clinical presentations and pathophysiology. Theoretical models that have been applied to FND and ASD, such as the Bayesian brain theory and the tripartite model of autism, may provide valuable insights into the intersection of these conditions. Although much of the current evidence remains speculative, it underscores the need for hypothesis-driven research to investigate these potential connections further.

CONCLUSION

ASD and FND are heterogeneous conditions that appear to co-occur in a subset of individuals, with overlapping symptomatology and possibly shared underlying mechanisms. This hypothesis-generating review emphasizes the need for further research to better understand these links, ultimately aiming to improve clinical recognition and develop targeted interventions that enhance the quality of life for affected individuals.

Altered Neural Processing of Interoception in Patients With Functional Neurological Disorder: A Task-Based fMRI Study

OBJECTIVE

Research suggests that disrupted interoception contributes to the development and maintenance of functional neurological disorder (FND); however, no functional neuroimaging studies have examined the processing of interoceptive signals in patients with FND.

METHODS

The authors examined univariate and multivariate functional MRI neural responses of 38 patients with mixed FND and 38 healthy control individuals (HCs) during a task exploring goal-directed attention to cardiac interoception-versus-control (exteroception or rest) conditions. The relationships between interoception-related neural responses, heartbeat-counting accuracy, and interoceptive trait prediction error (ITPE) were also investigated for FND patients.

RESULTS

When attention was directed to heartbeat signals versus exteroception or rest tasks, FND patients showed decreased neural activations (and reduced coactivations) in the right anterior insula and bilateral dorsal anterior cingulate cortices (among other areas), compared with HCs. For FND patients, heartbeat-counting accuracy was positively correlated with right anterior insula and ventromedial prefrontal activations during interoception versus rest. Cardiac interoceptive accuracy was also correlated with bilateral dorsal anterior cingulate activations in the interoception-versus-exteroception contrast, and neural activations were correlated with ITPE scores, showing inverse relationships to those observed for heartbeat-counting accuracy.

CONCLUSIONS

This study identified state and trait interoceptive disruptions in FND patients. Convergent between- and within-group findings contextualize the pathophysiological role of cingulo-insular (salience network) areas across the spectrum of functional seizures and functional movement disorder. These findings provide a starting point for the future development of comprehensive neurophysiological assessments of interoception for FND patients, features that also warrant research as potential prognostic and monitoring biomarkers.

Functional Movement Disorder Is Associated with Abnormal Interoceptive Brain Activity: A Task-based Functional MRI Study

Background

Aberrant interoceptive processing has been hypothesized to contribute to the pathophysiology of functional neurological disorder, although findings have been inconsistent. Here, we utilized functional magnetic resonance imaging (fMRI) to examine neural correlates of interoceptive attention - the conscious focus and awareness of bodily sensations - in functional movement disorder (FMD).

Methods

We used voxelwise analyses to compare blood oxygenation level-dependent responses between 13 adults with hyperkinetic FMD and 13 healthy controls (HCs) during a task requiring attention to different bodily sensations and to an exteroceptive stimulus. Additionally, we examined between-group differences in self-reported measures of interoception and evaluated their relationship with neural activity.

Results

Interoceptive conditions (heartbeat, stomach and 'body', indicating sensations from the body part or limb affected in FMD participants) activated a network involving the precuneus, the posterior cingulate cortex (PCC) and caudate nucleus (CN) bilaterally, and the right anterior insula (aINS) (p <0.05, corrected). Group differences in brain activity were mainly driven by processing of disease-related interoceptive signals, which in the FMD group was associated with a broader neural activation than monitoring gastric interoception, while no group differences were detected during cardiac interoception. Differences based on interoceptive focus (body vs heartbeat and stomach) between FMD subjects and HCs were found in PCC, CN, angular gyrus, thalamus, and in the mid-insula (p <0.05, corrected).

Conclusions

This is, to our knowledge, the first study showing that FMD is associated with abnormal interoceptive processing in regions involved in monitoring body state, attentional focus, and homeostatic inference.

Abnormal Cerebrospinal Fluid Cytology in Functional Movement Disorders

OBJECTIVE

The role of inflammation and neuroimmune mechanisms, which have been documented in various neuropsychiatric disorders including the seizure subtype of functional neurological disorder, remains unclear in functional movement disorders (FMD). To explore these mechanisms, we analyzed selected inflammatory markers in cerebrospinal fluid (CSF) in patients with FMD.

METHODS

We compared CSF markers in 26 patients with clinically established FMD (20 females; mean [SD] age = 43.3 [10.9], disease duration = 3.9 [3], range = 0.1-11 years; mean follow-up after lumbar puncture = 4.3 [2] years, range = 0.5-7 years) and 26 sex- and age-matched clinical controls with noninflammatory nonneurodegenerative neurological disorders, mostly sleep disorders.

RESULTS

Sixty-five percent of FMD patients versus 15% of controls showed cytological abnormalities (i.e., increased white blood cells [WBC] count, signs of WBC activation, or both; odds ratio [OR] = 9.85, 95% confidence interval = 2.37-52.00, p < .01, corrected), with a significantly higher frequency of an isolated lymphocytic activation, 35% versus 0% (OR = ∞, 95% confidence interval = 2.53-∞, p < .05, corrected). There were no differences in CSF protein and albumin levels, quotient albumin, IgG index, and oligoclonal bands. CSF abnormalities were not associated with more severe motor symptoms or a higher frequency of depression in FMD.

CONCLUSIONS

Our results suggest a possible involvement of immune mechanisms in the pathophysiology of (at least a subtype of) FMD that deserves further investigation.

Investigating psychobiological causes and mechanisms in functional seizures and functional motor symptoms: Study protocol

INTRODUCTION

Advances have been made in understanding the aetiology of functional neurological disorder (FND); however, its pathophysiological mechanisms have not been definitively demonstrated. Evidence suggests interacting roles for altered emotional processing and interoception, elevated autonomic arousal, and dissociation, but there is limited evidence demonstrating their causal influence on specific FND symptoms. Our superordinate aim is to elucidate potentially shared and distinct aetiological factors and mechanisms in two common FND subtypes, functional seizures (FS) and functional motor symptoms (FMS).

METHODS

This study has a multimodal, mixed between- and within-groups design. The target sample is 50 individuals with FS, 50 with FMS, 50 clinical controls (anxiety/depression), and 50 healthy controls. Potential aetiological factors (e.g., adverse life events, physical/mental health symptoms, dissociative tendencies, interoceptive insight/sensibility) will be assessed with a detailed medical history interview and self-report questionnaires. A laboratory session will include a neurocognitive battery, psychophysiological testing, cardiac interoception and time estimation tasks and an isometric handgrip task. A subsample will undergo magnetic resonance imaging, including structural, resting-state and task-based scans combined with psychophysiological recording. Remote monitoring with ecological momentary assessment and wearables will measure variability in FND symptoms and their potential predictors/correlates for ≥2 weeks in patients' daily lives. Longitudinal follow-ups at 3, 6, and 12-months will monitor longer-term outcomes in the clinical groups.

DISCUSSION

This study employs multimodal research methods to rigorously examine several putative mechanisms in FND, at subjective/experiential, behavioural, and physiological levels. The study will test causal hypotheses about the role of altered emotional processing, autonomic arousal, dissociation and interoception in the initiation or exacerbation of FND symptoms, directly comparing these processes in FS and FMS to healthy and clinical controls. This is the first study of its kind, with potential to reveal important targets for prevention and treatment of FND in future.

Predictive Processing and the Pathophysiology of Functional Neurological Disorder

The contemporary neuroscience understanding of the brain as an active inference organ supports that our conscious experiences, including sensorimotor perceptions, depend on the integration of probabilistic predictions with incoming sensory input across hierarchically organized levels. As in other systems, these complex processes are prone to error under certain circumstances, which may lead to alterations in their outcomes (i.e., variations in sensations and movements). Such variations are an important aspect of functional neurological disorder, a complex disorder at the interface of brain-mind-body interactions. Thus, predictive processing frameworks offer fundamental mechanistic insights into the pathophysiology of functional neurological disorder. In recent years, many of the aspects relevant to the neurobiology of functional neurological disorder - e.g., aberrant motor and sensory processes, symptom expectation, self-agency, and illness beliefs, as well as interoception, allostasis, and emotion - have been investigated through the lens of predictive processing frameworks. Here, we provide an overview of the current state of research on predictive processing and the pathophysiology of functional neurological disorder.

Unravelling the influence of affective stimulation on functional neurological symptoms: a pilot experiment examining potential mechanisms

BACKGROUND

Differences in affective processing have previously been shown in functional neurological disorder (FND); however, the mechanistic relevance is uncertain. We tested the hypotheses that highly arousing affective stimulation would result in elevated subjective functional neurological symptoms (FNS), and this would be associated with elevated autonomic reactivity. The possible influence of cognitive detachment was also explored.

METHOD

Individuals diagnosed with FND (motor symptoms/seizures; n=14) and healthy controls (n=14) viewed Positive, Negative and Neutral images in blocks, while passively observing the stimuli ('Watch') or detaching themselves ('Distance'). The FND group rated their primary FNS, and all participants rated subjective physical (arousal, pain, fatigue) and psychological states (positive/negative affect, dissociation), immediately after each block. Skin conductance (SC) and heart rate (HR) were monitored continuously.

RESULTS

FNS ratings were higher after Negative compared with Positive and Neutral blocks in the FND group (p=0.002, ηp 2=0.386); however, this effect was diminished in the Distance condition relative to the Watch condition (p=0.018, ηp 2=0.267). SC and/or HR correlated with FNS ratings in the Negative-Watch and Neutral-Distance conditions (r values=0.527-0.672, p values=0.006-0.035). The groups did not differ in subjective affect or perceived arousal (p values=0.541-0.919, ηp 2=<0.001-0.015).

CONCLUSIONS

Emotionally significant events may exert an influence on FNS which is related to autonomic activation rather than altered subjective affect or perceived arousal. This influence may be modulated by cognitive detachment. Further work is needed to determine the relevance and neural bases of these processes in specific FND phenotypes.

Illness representations of people with later-onset functional seizures

PURPOSE

Although functional seizures can start at any age, little is known about the individuals for whom onset occurs after the age of 40. It has been proposed that health-related traumatic events are more relevant causal factors for people with 'later-onset functional seizures' than for those whose functional seizures begin earlier in life, however, the illness representations of people with later-onset functional seizures have not yet been investigated. This study aimed to understand the experiences and illness representations of people with later-onset functional seizures.

METHODS

This was a mixed-methods study. People with later-onset functional seizures were recruited via a neurologist's caseload and online membership-led organisations. Semi-structured interview transcripts were analysed using Template Analysis according to the Common-Sense Model (CSM). Self-report measures of demographic and clinical details were collected to characterise the sample and verify themes.

RESULTS

Eight people with later-onset functional seizures participated in the study. Illness representations relating to all domains of the CSM as well as an additional theme of 'Triggers' were identified. Functional seizures were characterised as a mysterious brain disorder analogous to a computer malfunction and involving involuntary movements associated with alterations in consciousness. Perceptions of duration were indefinite, and triggers were unknown or at the extremes of autonomic arousal. Half of the sample identified health-related events/trauma as causal. Opinions were divided on 'cumulative life stress' as a causal factor. Most perceived themselves to have limited or no control but having 'control' over seizures was conceptualised as different to reducing their likelihood, frequency, or impact. Later-onset functional seizures were viewed as being more detrimental for caring and financial responsibilities but to have advantages for acceptance.

CONCLUSIONS

This is the first study to assess the illness representations of people with later-onset functional seizures. Many themes were similar to those identified in samples including people with earlier-onset functional seizures. Health-related trauma or events were the most strongly endorsed perceived causal factor, but with the exception of 'consequences', all representations were characterised by uncertainty. Clinicians should hold in mind the interaction between life stage and the consequences of later-onset functional seizures.

Functional neurological seizures and migraine: A systematic review and case series

BACKGROUND

The seizure subtype of functional neurological disorder (FND-seizures) is a common neuropsychiatric condition manifesting with episodic epilepsy-like events. Despite the common belief that FND-seizures are precipitated by psychological stressors, neurological disorders may also be triggers. In 1890, Babinski described four cases of FND symptoms associated with migraine attacks. Despite the passing of more than 130 years since this first clinical observation, the relationship between FND-seizures and migraine is not fully elucidated.

OBJECTIVES

(1) To complete a systematic review of the literature that investigated potential associations between FND-seizures and migraine and the response of FND seizures to treatment with migraine prophylactic medications (2). To undertake a retrospective study of patients with FND-seizures and migraine, including response to migraine prophylaxis.

METHODS

(1) Using PRISMA methods, we completed a systematic review of EMBASE and Scopus databases from inception to March 31, 2021, for literature on FND-seizures and migraine. (2) Our multi-disciplinary team, including subspecialists in psychosomatic medicine, epilepsy, and headache disorders, reviewed consecutive patients diagnosed with FND-seizures and migraine to assess potential causal associations and responses to standard migraine prophylactic medications.

RESULTS

(1) The search yielded seven studies from 126 screened manuscripts (N = 1,186 patients with FND-seizures; mean age 38.7 years; 72.6% female). They varied substantially in design, population, diagnostic measures, and outcomes. Nevertheless, all studies found associations between FND-seizures and migraine, which were stronger than those between epileptic seizures and migraine in comparative investigations, but provided limited information on treatment response. (2) In our case series, investigators reached unanimous consensus that migraine attacks triggered FND-seizures in 28/43 (65.1%) patients reviewed (mean age, 38.8 years; 74% female). In 19/26 (73%) patients with adequate follow-up data, treatment with migraine prophylactic medications alone (no behavioral interventions) concomitantly reduced FND-seizure and headache frequency by >50%.

CONCLUSION

Our systematic review and case series indicate that migraine attacks may trigger FND-seizures, perhaps more often that currently understood, and suggest that migraine prophylaxis may reduce FND-seizure frequency in such cases. To validate these observations, fully powered prospective investigations are required.

Interoception in functional motor symptoms and functional seizures: Preliminary evidence of intact accuracy alongside reduced insight and altered sensibility

Altered interoception may be a pathophysiological mechanism in functional neurological disorder (FND). However, findings have been inconsistent across interoceptive dimensions in FND including functional motor symptoms (FMS) and seizures (FS). Here, individuals with FMS/FS (n = 17) and healthy controls (HC, n = 17) completed measures of interoceptive accuracy and insight (adapted heartbeat tracking task [HTT] with confidence ratings), a time estimation control task (TET) and the Multidimensional Assessment of Interoceptive Awareness-2 (MAIA-2) to assess interoceptive sensibility. The groups did not differ in interoceptive accuracy (p = 1.00, g = 0.00) or confidence (p = .99, g = 0.004), although the FMS/FS group displayed lower scores on the "Not-Distracting" (p < .001, g = 1.42) and "Trusting" (p = .005, g = 1.17) MAIA-2 subscales, relative to HCs. The groups did not differ in TET performance (p = .82, g = 0.08). There was a positive relationship between HTT accuracy and confidence (insight) in HCs (r = .61, p = .016) but not in FMS/FS (r = 0.11, p = .69). HTT confidence was positively correlated with MAIA-2 "Self-Regulation" (r = 0.77, p = .002) and negatively correlated with FND symptom severity (r = -0.84, p < .001) and impact (r = -0.86, p < .001) in FMS/FS. Impaired interoceptive accuracy may not be a core feature in FMS/FS, but reduced insight and altered sensibility may be relevant. Reduced certainty in self-evaluations of bodily experiences may contribute to the pathogenesis of FND symptoms.

[Mother brain: Bayesian theory of maternal interoception during pregnancy and postpartum]

The perinatal period, including pregnancy and postpartum, causes major morphological, endocrinal, and thermal transitions in women. As the fetus grows, abdominal muscle fibers stretch, internal organs such as the bladder or colon move, and the uterine anatomy changes. Many of these changes involve interoception, the perception of internal body signals such as muscle and visceral sensations. Despite the importance of these interoceptive signals, few studies have explored perinatal interoception. We propose an innovative theory of maternal interoception based on recent findings in neuroscience. We show that interoceptive signals processing during pregnancy is crucial for understanding perinatal phenomenology and psychopathology, such as maternal perception of fetal movements, maternal-infant bonding, denial of pregnancy, phantom fetal movements after childbirth, pseudocyesis or even puerperal delusion. Knowing the importance of these interoceptive mechanisms, clinicians in obstetrics, gynecology and mental health should be particularly vigilant to maternal interoception during the perinatal period.

A new science of emotion: implications for functional neurological disorder

Functional neurological disorder reflects impairments in brain networks leading to distressing motor, sensory and/or cognitive symptoms that demonstrate positive clinical signs on examination incongruent with other conditions. A central issue in historical and contemporary formulations of functional neurological disorder has been the mechanistic and aetiological role of emotions. However, the debate has mostly omitted fundamental questions about the nature of emotions in the first place. In this perspective article, we first outline a set of relevant working principles of the brain (e.g. allostasis, predictive processing, interoception and affect), followed by a focused review of the theory of constructed emotion to introduce a new understanding of what emotions are. Building on this theoretical framework, we formulate how altered emotion category construction can be an integral component of the pathophysiology of functional neurological disorder and related functional somatic symptoms. In doing so, we address several themes for the functional neurological disorder field including: (i) how energy regulation and the process of emotion category construction relate to symptom generation, including revisiting alexithymia, 'panic attack without panic', dissociation, insecure attachment and the influential role of life experiences; (ii) re-interpret select neurobiological research findings in functional neurological disorder cohorts through the lens of the theory of constructed emotion to illustrate its potential mechanistic relevance; and (iii) discuss therapeutic implications. While we continue to support that functional neurological disorder is mechanistically and aetiologically heterogenous, consideration of how the theory of constructed emotion relates to the generation and maintenance of functional neurological and functional somatic symptoms offers an integrated viewpoint that cuts across neurology, psychiatry, psychology and cognitive-affective neuroscience.

Interoception Dysfunction Contributes to the Negative Emotional Bias in Major Depressive Disorder

Background

Previous research studies have demonstrated that impaired interoception is involved in emotional information processing in major depressive disorder (MDD). Heartbeat-evoked potential (HEP) amplitudes, an index for interoception, could be manipulated by emotional faces in healthy people. Considering negative emotional bias is the core characteristic in MDD, we hypothesized that interoception dysfunction was associated with the negative emotional bias in MDD.

Methods

An electroencephalogram (EEG) study under an emotional faces task was applied to explore the relationship between interoception and emotional bias. HEPs before emotional faces stimuli were used to predict the late positive potential (LPP) amplitudes and it worked as an index of emotional bias. Twenty-seven patients with MDD and 27 healthy controls (HCs) participated in this study. Source analysis gave an auxiliary description for results in sensory level.

Results

Major depressive disorders (MDDs) had poor performance in the heartbeat count task (HCT) and attenuate HEP average amplitudes (455-550 ms). Compared with HCs, cluster-based permutation t-tests revealed that MDDs had attenuated LPP amplitudes (300-1,000 ms) over centroparietal regions and enhanced LPP amplitudes over frontocentral regions. Furthermore, abnormal attenuated HEPs could predict aberrant LPPs under sad face stimuli in MDDs, which could be associated with the dysfunction of the anterior cingulate cortex (ACC) and right insula.

Conclusion

Mediated by ACC and insula, interoception dysfunction contributes to the negative emotional bias of MDD, highlighting the importance of interoception in the disorder.

Shame in patients with psychogenic nonepileptic seizure: A narrative review

Psychogenic Nonepileptic Seizures (PNES) have been linked to dysregulated emotions and arousal. However, the question which emotions may be most relevant has received much less attention. In this multidisciplinary narrative review, we argue that the self-conscious emotion of shame is likely to be of particular importance for PNES. We summarize current concepts of the development of shame processing and its relationship with other emotional states. We demonstrate the potential of acute shame to cause a sudden disruption of normal cognitive function and trigger powerful behavioral, cognitive, physiological and secondary emotional responses which closely resemble key components of PNES. These responses may lead to the development of shame avoidance strategies which can become disabling in themselves. We discuss how excessive shame proneness and shame dysregulation are linked to several psychopathologies often associated with PNES (including depression and PTSD) and how they may predispose to, precipitate and perpetuate PNES disorders, not least by interacting with stigma. We consider current knowledge of the neurobiological underpinnings of shame and PNES. We explore how shame could be the link between PNES and a heterogeneous range of possible etiological factors, and how it may link historical aversive experiences with individual PNES events occurring much later and without apparent external trigger. We argue that, in view of the potential direct links between shame and PNES, the well-documented associations of shame with common comorbidities of this seizure disorder and the well-characterized relationship between chronic shame and stigma, there is a compelling case to pay greater attention to shame in relation to PNES. Its role in the treatment of patients with PNES is discussed in a separate, linked review incorporating case vignettes to highlight the complex interactions of different but interlinked shame-related issues in individual patients.

Subjective versus objective measures of distress, arousal and symptom burden in patients with functional seizures and other functional neurological symptom disorder presentations: A systematic review

Symptoms and functioning can be measured subjectively using self-report measures or objectively, based on physiological changes. This raises the question whether subjective and objective measures are closely correlated and - if not - whether one is more accurate or meaningful than the other, especially in patients with Functional Seizures (FS) or other Functional Neurological Symptom Disorders (FND), where subjective and objective observations may be thought particularly likely to deviate. This systematic review explores these questions focussing on measures of distress, arousal and symptom burden. Eighteen studies (12 FS, 6 other FND) capturing 396 FND patients were included. Eleven reported no correlation between subjective and objective measures. Only four studies reported significant correlations (r's = -0.74-0.59, p's < 0.05). The small number of studies and diverse methodologies do not provide conclusive answers to the questions posed. Given that subjective and objective measures capture different aspects of current state or function, a combination of measurement approaches is likely to provide optimal information about patients' health state. In view of the attentional and perceptual alterations implicated in FND, the difference between objective and subjective measures may represent an interesting observation in its own right.