Autonomic and subjective responsivity to emotional images in people with dissociative seizures

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.

Objective and subjective neurocognitive functioning in functional motor symptoms and functional seizures: preliminary findings

INTRODUCTION

This study aimed to provide a preliminary assessment of objective and subjective neurocognitive functioning in individuals with functional motor symptoms (FMS) and/or functional seizures (FS). We tested the hypotheses that the FMS/FS group would display poorer objective attentional and executive functioning, altered social cognition, and reduced metacognitive accuracy.

METHOD

Individuals with FMS/FS (n = 16) and healthy controls (HCs, n = 17) completed an abbreviated CANTAB battery, and measures of intellectual functioning, subjective cognitive complaints, performance validity, and comorbid symptoms. Subjective performance ratings were obtained to assess local metacognitive accuracy.

RESULTS

The groups were comparable in age (p = 0.45), sex (p = 0.62), IQ (p = 0.57), and performance validity (p-values = 0.10-0.91). We observed no impairment on any CANTAB test in this FMS/FS sample compared to HCs, although the FMS/FS group displayed shorter reaction times on the Emotional Bias task (anger) (p = 0.01, np2 = 0.20). The groups did not differ in subjective performance ratings (p-values 0.15). Whilst CANTAB attentional set-shifting performance (total trials/errors) correlated with subjective performance ratings in HCs (p-values<0.005, rs = -0.85), these correlations were non-significant in the FMS/FS sample (p-values = 0.10-0.13, rs-values = -0.46-0.50). The FMS/FS group reported more daily cognitive complaints than HCs (p = 0.006, g = 0.92), which were associated with subjective performance ratings on CANTAB sustained attention (p = 0.001, rs = -0.74) and working memory tests (p < 0.001, rs = -0.75), and with depression (p = 0.003, rs = 0.70), and somatoform (p = 0.003, rs = 0.70) and psychological dissociation (p-values<0.005, rs-values = 0.67-0.85).

CONCLUSIONS

These results suggest a discordance between objective and subjective neurocognitive functioning in this FMS/FS sample, reflecting intact test performance alongside poorer subjective cognitive functioning. Further investigation of neurocognitive functioning in FND subgroups is necessary.

The neurobiology of functional neurological disorders characterised by impaired awareness

We review the neurobiology of Functional Neurological Disorders (FND), i.e., neurological disorders not explained by currently identifiable histopathological processes, in order to focus on those characterised by impaired awareness (functionally impaired awareness disorders, FIAD), and especially, on the paradigmatic case of Resignation Syndrome (RS). We thus provide an improved more integrated theory of FIAD, able to guide both research priorities and the diagnostic formulation of FIAD. We systematically address the diverse spectrum of clinical presentations of FND with impaired awareness, and offer a new framework for understanding FIAD. We find that unraveling the historical development of neurobiological theory of FIAD is of paramount importance for its current understanding. Then, we integrate contemporary clinical material in order to contextualise the neurobiology of FIAD within social, cultural, and psychological perspectives. We thus review neuro-computational insights in FND in general, to arrive at a more coherent account of FIAD. FIAD may be based on maladaptive predictive coding, shaped by stress, attention, uncertainty, and, ultimately, neurally encoded beliefs and their updates. We also critically appraise arguments in support of and against such Bayesian models. Finally, we discuss implications of our theoretical account and provide pointers towards an improved clinical diagnostic formulation of FIAD. We suggest directions for future research towards a more unified theory on which future interventions and management strategies could be based, as effective treatments and clinical trial evidence remain limited.

Emotional arousal in patients with functional movement disorders: A pupillometry study

OBJECTIVE

Pathophysiology explanations for functional movement disorders often assume a role for emotional hyperarousal. Pupillometry is a validated method for evaluation of emotional arousal by detecting changes in pupil size in response to emotional stimuli. In a case-control study design, we aimed to study objective and subjective emotional arousal using pupillometry and affective ratings. To assess attentional engagement by affective stimuli, we used videooculographic tracking of eye movement patterns (scanpath).

METHODS

Twenty-five female patients with functional movement disorders (mean age: 40.9 [SD 12.7] years) and 23 age matched healthy female controls participated in the study. Using infrared high-resolution eye-tracker, both pupil size and eye movement pattern in response to emotionally charged erotic, adventure, threat, victim, and neutral pictures were recorded along with subjective ratings of emotional valence and arousal of the presented pictures.

RESULTS

A between-group comparison showed significantly smaller pupil dilation to adventure stimuli compared to neutral stimuli in patients compared to controls (P < 0.004, bootstrap, uncorr., adj. η2 = 0.00). No significant difference in pupillary response to other stimuli and scanpath parameters was found between the groups. Patients rated significantly lower emotional arousal to erotic pictures than controls (P < 0.001, bootstrap, uncorr., adj. η2 = 0.09).

CONCLUSION

This study did not find evidence of autonomous or subjective emotional hyperarousal. The mismatch between objective autonomic measures and subjective arousal ratings in patients is of pathophysiological interest and in line with recent findings of impaired interoception in functional movement disorders.

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.

Functional (psychogenic non-epileptic/dissociative) seizures: why and how?

Functional seizures (FS) known also as psychogenic non-epileptic seizures or dissociative seizures, present with ictal semiological manifestations, along with various comorbid neurological and psychological disorders. Terminology inconsistencies and discrepancies in nomenclatures of FS may reflect limitations in understanding the neuropsychiatric intricacies of this disorder. Psychological and neurobiological processes of FS are incompletely understood. Nevertheless, important advances have been made on underlying neuropsychopathophysiological mechanisms of FS. These advances provide valuable information about the underlying mechanisms of mind-body interactions. From this perspective, this narrative review summarises recent studies about aetiopathogenesis of FS at two levels: possible risk factors (why) and different aetiopathogenic models of FS (how). We divided possible risk factors for FS into three categories, namely neurobiological, psychological and cognitive risk factors. We also presented different models of FS based on psychological and neuroanatomical understanding, multilevel models and integrative understanding of FS. This work should help professionals to better understand current views on the multifactorial mechanisms involved in the development of FS. Shedding light on the different FS profiles in terms of aetiopathogenesis will help guide how best to direct therapy, based on these different underlying mechanisms.

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.

Autonomic, Endocrine, and Inflammation Profiles in Functional Neurological Disorder: A Systematic Review and Meta-Analysis

OBJECTIVE

Functional neurological disorder (FND) is a core neuropsychiatric condition. To date, promising yet inconsistently identified neural circuit profiles have been observed in patients with FND, suggesting that gaps remain in our systems-level neurobiological understanding. As such, other important physiological variables, including autonomic, endocrine, and inflammation findings, need to be contextualized for a more complete mechanistic picture.

METHODS

The investigators conducted a systematic review and meta-analysis of available case-control and cohort studies of FND. PubMed, PsycINFO, and Embase databases were searched for studies from January 1, 1900, to September 1, 2020, that investigated autonomic, endocrine, and inflammation markers in patients with FND. Sixty-six of 2,056 screened records were included in the review, representing 1,699 patients; data from 20 articles were used in the meta-analysis.

RESULTS

Findings revealed that children and adolescents with FND, compared with healthy control subjects (HCs), have increased resting heart rate (HR); there is also a tendency toward reduced resting HR variability in patients with FND across the lifespan compared with HCs. In adults, peri-ictal HR differentiated patients with functional seizures from those with epileptic seizures. Other autonomic and endocrine profiles for patients with FND were heterogeneous, with several studies highlighting the importance of individual differences.

CONCLUSIONS

Inflammation research in FND remains in its early stages. Moving forward, there is a need for the use of larger sample sizes to consider the complex interplay between functional neurological symptoms and behavioral, psychological, autonomic, endocrine, inflammation, neuroimaging, and epigenetic/genetic data. More research is also needed to determine whether FND is mechanistically (and etiologically) similar or distinct across phenotypes.

Evidence of objective sleep impairment in nonepileptic attack disorder: A naturalistic prospective controlled study using actigraphy and daily sleep diaries over six nights

Poor sleep is reported by many with nonepileptic attack disorder (NEAD) with correlations evident between self-reported sleep quality and mood and functional impairment. However, it is contended that self-reported sleep impairment in NEAD is a subjective phenomenon, which represents a general tendency to over-report symptoms or misinterpret bodily states in those with NEAD. The present study was therefore designed to investigate the extent of subjective and objective sleep impairments in those with NEAD. Over six nights we prospectively recorded comparable nightly objective (actigraphy) and subjective (consensus sleep diary) sleep parameters in a sample of 17 people with NEAD, and an age- and gender-matched normative control group (N = 20). Participants recorded daily measures of attacks, dissociation, and mood. Alongside higher subjective sleep impairment, the NEAD group had significantly worse objective sleep on several metrics compared to the normative controls, characterized by disrupted sleep (frequent awakenings and wake after sleep onset, low efficiency). Exploratory analyses using mixed effects models showed that attacks were more likely to occur on days preceded by longer, more restful sleep. This study, which had good ecological validity, evidences the presence of objective sleep impairment in NEAD, suggesting that in patient reports of problems with sleep should be given careful consideration in clinical practice.

Are Functional (Psychogenic Nonepileptic) Seizures the Sole Expression of Psychological Processes?

Functional [psychogenic nonepileptic/dissociative] seizures (FND-seiz) and related functional neurological disorder subtypes were of immense interest to early founders of modern-day neurology and psychiatry. Unfortunately, the divide that occurred between the both specialties throughout the mid-twentieth century placed FND-seiz at the borderland between the two disciplines. In the process, a false Cartesian dualism emerged that labeled psychiatric conditions as impairments of the mind and neurological conditions as disturbances in structural neuroanatomy. Excitingly, modern-day neuropsychiatric perspectives now consider neurologic and psychiatric conditions as disorders of both brain and mind. In this article, we aim to integrate neurologic and psychiatric perspectives in the conceptual framing of FND-seiz. In doing so, we explore emerging relationships between symptoms, neuropsychological constructs, brain networks, and neuroendocrine/autonomic biomarkers of disease. Evidence suggests that the neuropsychological constructs of emotion processing, attention, interoception, and self-agency are important in the pathophysiology of FND-seiz. Furthermore, FND-seiz is a multi-network brain disorder, with evidence supporting roles for disturbances within and across the salience, limbic, attentional, multimodal integration, and sensorimotor networks. Risk factors, including the magnitude of previously experienced adverse life events, relate to individual differences in network architecture and neuroendocrine profiles. The time has come to use an integrated neuropsychiatric approach that embraces the closely intertwined relationship between physical health and mental health to conceptualize FND-seiz and related functional neurological disorder subtypes.

Interoception and stress in patients with Functional Neurological Symptom Disorder

INTRODUCTION

Research suggests that patients with Functional Neurological Symptom Disorder (pwFND) struggle to identify their own emotions and associated physiological cues (interoceptive sensitivity, IS). However, it is not known how this deficit interacts with stress. This study aimed to assess IS in pwFND at baseline and following stress induction, and relate the findings to self-reported emotion processing difficulties.

METHODS

Twenty-six pwFND and 27 healthy controls performed the Heart Beat Detection Task pre- and post-stress induction with the Cold Pressor Test. Participants also completed questionnaires assessing anxiety (GAD-7) and depressive symptomology (PHQ-9), as well as emotion processing (EPS-25).

RESULTS

Patients reported deficits in emotion processing (p < . 001) and had lower IS (p = .032) than healthy controls. IS improved following stress induction across both groups (p = .003) but patients' IS was lower than that of healthy controls' pre-and post-stress induction. Exploratory analyses revealed that patients reporting sensory symptoms had lower IS at baseline than patients who did not.

CONCLUSION

Our findings suggest that pwFND are relatively impaired in the identification of their emotions at baseline and following stress induction. This may be related to the experience of functional sensory symptoms and has implications for the psychological treatment of emotion dysregulation in this population.

Individual differences in interoceptive accuracy and prediction error in motor functional neurological disorders: A DTI study

In motor functional neurological disorders (mFND), relationships between interoception (a construct of high theoretical relevance to its pathophysiology) and neuroanatomy have not been previously investigated. This study characterized white matter in mFND patients compared to healthy controls (HCs), and investigated associations between fiber bundle integrity and cardiac interoception. Voxel‐based analysis and tractography quantified fractional anisotropy (FA) in 38 mFND patients compared to 38 HCs. Secondary analyses compared functional seizures (FND‐seiz; n = 21) or functional movement disorders (n = 17) to HCs. Network lesion mapping identified gray matter origins of implicated fiber bundles. Within‐group mFND analyses investigated relationships between FA, heartbeat tracking accuracy and interoceptive trait prediction error (discrepancies between interoceptive accuracy and self‐reported bodily awareness). Results were corrected for multiple comparisons, and all findings were adjusted for depression and trait anxiety. mFND and HCs did not show any between‐group interoceptive accuracy or FA differences. However, the FND‐seiz subgroup compared to HCs showed decreased integrity in right‐lateralized tracts: extreme capsule/inferior fronto‐occipital fasciculus, arcuate fasciculus, inferior longitudinal fasciculus, and thalamic/striatum to occipital cortex projections. These alterations originated predominantly from the right temporoparietal junction and inferior temporal gyrus. In mFND patients, individual differences in interoceptive accuracy and interoceptive trait prediction error correlated with fiber bundle integrity originating from the insula, temporoparietal junction, putamen and thalamus among other regions. In this first study investigating brain‐interoception relationships in mFND, individual differences in interoceptive accuracy and trait prediction error mapped onto multimodal integration‐related fiber bundles. Right‐lateralized limbic and associative tract disruptions distinguished FND‐seiz from HCs.

Psychogenic non-epileptic seizures in children - psychophysiology & dissociative characteristics

The purpose of this study was to determine psychophysiology and dissociative characteristics of psychogenic non-epileptic seizures (PNES) in a clinical pediatric setting. A retrospective chart review was conducted over a 5-year period that included children meeting criteria for probable, clinically established or documented PNES. Of these, 33 patients (81%) underwent psychophysiology assessment as part of standardized care and were selected for study inclusion. Ages ranged from 10 to 17 years inclusive (70% female). The majority of patients were found to have some form of autonomic decompensation at baseline (82%) and lack of autonomic recovery from a cognitive stressor (58%). Inhibition of electrodermal skin response to laboratory stressor was associated with significantly longer duration of PNES illness (t=2.65, p=.013), while elevated heart rate (above 90^th percentile) was associated with significantly higher frequency of PNES events in the month preceding diagnosis (t=3.1, p=.004). High levels of dissociation and hyperventilation symptoms were self-reported by adolescent patients (n=19) with a moderate degree of positive association (r=0.35, p=.038). The majority of patients (n= 25, 89%) were taught to correct respiratory CO₂ levels during a single biofeedback training session. Conclusions: Child PNES populations appear to be characterized by chronic autonomic hyperarousal reflecting severity of their symptoms, which can feasibly be targeted for behavioral treatment.

Emotional Reactivity as a Vulnerability for Psychogenic Nonepileptic Seizures? Responses While Reliving Specific Emotions

OBJECTIVE

Dysfunction in emotional processes is a hypothesized contributor to functional neurological disorders (FNDs), yet few studies have evoked real-time emotion during multimethod assessment incorporating subjective, behavioral, and psychophysiological indicators. This approach may reveal clinical and neurobiological vulnerability to FND and clarify how dysfunctional emotional processes serve as perpetuating factors.

METHODS

Eleven participants with video-EEG-confirmed diagnoses of psychogenic nonepileptic seizures (PNES) were compared with 49 seizure-free trauma control subjects (TCs) with or without clinically elevated posttraumatic stress symptoms (25 clinically elevated [TC-clin], 24 not clinically elevated [TC-nonclin]). Participants recalled and described memories evoking anger, shame, happiness, and neutral feelings.

RESULTS

Even though PNES patients and TCs reported similar amounts of emotional experience, PNES patients reported more difficulty reliving emotions and were less likely to complete the relived shame task. During and after reliving happiness, PNES and TC-clin groups showed respiratory sinus arrhythmia (RSA) decreases, indicating parasympathetic withdrawal, whereas the TC-nonclin group showed RSA increases.

CONCLUSIONS

Findings from this pilot study are consistent with previous research and clinical observations that emotional engagement may be more effortful for PNES patients. Patterns of RSA change, which may also point to greater effortful engagement, were similar in PNES and TC-clin groups, suggesting that traumatic stress reactions may play a part. At the same time, experience of greater difficulty or avoidance may be even greater among PNES patients. Especially when regulatory resources are already limited, accumulated effort, coupled with self-threatening contexts such as shame, may be particularly problematic for those with PNES and perhaps other FNDs.

Skin conductance response and emotional response in women with psychogenic non-epileptic seizures

PURPOSE

Recent etiopathogenic models place emotional dysregulation at the core of psychogenic nonepileptic seizure (PNES). Our purpose was to assess physiological, cognitive, and behavioral emotional responses of PNES patients.

METHODS

This study compared three types of emotional responses to visual emotional stimuli between 34 female PNES group and 34 matched healthy controls: physiological response measured by skin conductance response (SCR) (rate, amplitude and latency) and heart rate deceleration; cognitive response measured by valence and arousal elicited by the images; and behavioural response measured by latency of ratings. The groups were characterized on psychiatric comorbidities, traumatic history, alexithymia, and dissociation.

RESULTS

Compared to controls, PNES group displayed lower SCR for all images (p = 0.038), shorter amplitude of heart rate deceleration (p = 0.024) and faster arousal rating for all images (p = 0.019), but no difference on cognitive rating of images. Within-groups analyses showed only in PNES subjects increased rate (+19.35%, p = 0.046) SCR for negative stimuli with strong arousal compared to negative with low arousal. PNES physiological response (SCR and heart rate deceleration) was negatively correlated to dissociation tendency (r=-0.48, p = 0.0083) and alexithymia (r=-0.44, p = 0.012)). For cognitive response, no correlation was found.

CONCLUSION

These results are in favour of a lower physiological emotional response but with an over-reactivity at behavioral level contrasting with similar cognitive assessment. For strong aversive stimuli, PNES might present a trend to overreact at physiological and behavioural levels. Our results suggest that dissociation and difficulty in describing feelings are associated with an altered physiological response in PNES women only.

Dissociation and interoception in functional neurological disorder

Introduction: We aimed to examine susceptibility to dissociation and the impact of dissociation on interoceptive processing in individuals with functional neurological disorder (FND). We hypothesised that dissociative states would be elevated and interoceptive accuracy and awareness impaired at baseline in people with FND, and that such differences would be exacerbated following acute dissociation. Methods: Nineteen adults with FND were compared to 20 healthy controls. A modified heart-beat tracking task measured interoceptive accuracy and awareness (confidence) before and after a validated dissociation induction procedure. An exteroceptive processing control task was included. Mann-Whitney tests and r-values (effect size) were computed for between-group comparisons. Results: The FND group displayed elevated dissociation at baseline (p = 0.001, r = 0.528) compared to controls which increased following dissociation-induction (p < 0.001, r = 0.663). Interoceptive accuracy did not differ between groups at baseline (p = 0.967, r = 0.009); however, the FND group had lower accuracy scores post-induction (p = 0.021, r = 0.379). A negative correlation (trend) between change scores for dissociation and interoceptive accuracy was noted (r_s = -0.411, p = 0.057). Confidence ratings on interoceptive and exteroceptive processing tasks were lower in the FND group (p-values < 0.05 or <0.01, r-values 0.331-0.489). Conclusions: Individuals with FND experienced greater susceptibility to dissociation, metacognitive deficits and impaired interoceptive accuracy than controls after acute dissociation.

Psychogenic nonepileptic seizures in children-Prospective validation of a clinical care pathway & risk factors for treatment outcome

PURPOSE

The purpose of this study was to prospectively validate a care pathway for psychogenic nonepileptic seizures (PNES) in a pediatric setting. The pathway was developed based on a previous study of patients at our center, which demonstrated positive treatment outcomes of 80% full or partial remission. Sequentially referred patients with PNES in the validation cohort received care prospectively according to the pathway algorithm. It was hypothesized that the validation cohort would achieve outcomes similar to that of the development cohort as a result of standardized care.

METHOD

We performed a retrospective chart review of 43 children sequentially referred, assessed, and treated within a specialized neurology psychology service for suspected PNES over a 5-year period. The majority of patients (n = 41, 95%) met diagnostic criteria for probable, clinically established, or documented PNES, according to the International League Against Epilepsy (ILAE) criteria.

RESULTS

Ages ranged from 6 to 18 years of age at time of diagnosis, with the majority of patients being female (n = 29, 67%) and adolescent (n = 31, 72%). There was a high level of adherence to the care algorithm (n = 34, 84%). The development and validation cohorts were similar across demographic, clinical, and psychological characteristics. Standardized care resulted in high rates of full (n = 27, 63%) and partial (n = 12, 28%) remission, as self-reported at discharge. A 96% decrease in mean monthly frequency of total PNES events was also observed at discharge, as was a significant reduction in healthcare utilization related to PNES (74% fewer ambulance calls and 85% fewer emergency department (ED) visits). Post hoc analyses demonstrated that duration of PNES illness longer than 12 months (at diagnosis) increased odds of not achieving full remission by discharge (odds ratio = 5.94, p = 0.02). Developmental period of onset (child versus adolescent), having abnormal electroencephalogram (EEG) result, previous concussion, chronic versus acute stressor, more than one PNES event type, or additional functional neurological symptoms did not significantly impact treatment response.

CONCLUSIONS

This study demonstrates, for the first time prospectively in a pediatric setting, that standardized care for PNES leads to improved clinical outcomes and reduced healthcare utilization. Delayed diagnosis and treatment of PNES longer than 12 months also appears to be associated with less favorable outcomes in children.

Clinical characteristics of psychogenic nonepileptic seizures across the lifespan: An international retrospective study

PURPOSE

Previous studies from a few countries have reported semiological differences in younger children compared with adolescents or adults with psychogenic nonepileptic seizures (PNESs). This study tested the hypothesis that semiological, demographic, and historical risk factors vary with different ages of PNES onset in a large cohort from different countries.

METHODS

In this retrospective study, we investigated patients consecutively referred for PNES, who were admitted to epilepsy monitoring units in Iran, Brazil, Venezuela, Canada, Argentina, and USA. Age, gender, age at seizure onset, seizure semiology, and factors predisposing to PNES (abuse, stressors) were documented according to routine diagnostic practices at each center. Participants were grouped according to their age at onset (i.e., childhood, adolescence, or adulthood).

RESULTS

A total of 448 patients were studied. Female predominance was associated with adolescent- (85/122, 70%) and adult-onset (190/270, 70%) but not in childhood-onset PNES (28/56, 50%) (p = 0.011). Event frequency in the month preceding the diagnosis was higher in the childhood- [x¯ = 50, standard deviation (sd) = 82, p = 0.025] versus adolescent- (x¯ = 24, sd = 36) or adult-onset groups (x¯ = 29, sd = 61). Significant between-group differences were observed for generalized body movements (p = 0.0001) and ictal injury (p = 0.027), suggesting more severe ictal presentations in adult-onset PNES compared with younger ages. Adult-onset patients were also more likely to be taking an unnecessary antiepileptic medication (p = 0.010).

CONCLUSION

While PNES may present at any age, there appear to be notable differences across the lifespan with respect to some of the clinical characteristics. Further international and cross-cultural studies may reveal other interesting characteristics of PNES.

Emotional processing in functional neurological disorder: a review, biopsychosocial model and research agenda

Functional neurological disorder (FND) is a common and highly disabling disorder, but its aetiology remains enigmatic. Conceptually, there has been reduced emphasis on the role of psychosocial stressors in recent years, with a corresponding increase in neurobiological explanations. However, a wealth of evidence supports the role of psychosocial adversities (eg, stressful life events, interpersonal difficulties) as important risk factors for FND. Therefore, there is a need to integrate psychosocial (environmental) and neurobiological factors (eg, sensorimotor and cognitive functions) in contemporary models of FND. Altered emotional processing may represent a key link between psychosocial risk factors and core features of FND. Here, we summarise and critically appraise experimental studies of emotional processing in FND using behavioural, psychophysiological and/or neuroimaging measures in conjunction with affective processing tasks. We propose that enhanced preconscious (implicit) processing of emotionally salient stimuli, associated with elevated limbic reactivity (eg, amygdala), may contribute to the initiation of basic affective/defensive responses via hypothalamic and brainstem pathways (eg, periaqueductal grey). In parallel, affect-related brain areas may simultaneously exert a disruptive influence on neurocircuits involved in voluntary motor control, awareness and emotional regulation (eg, sensorimotor, salience, central executive networks). Limbic-paralimbic disturbances in patients with FND may represent one of several neurobiological adaptations linked to early, severe and/or prolonged psychosocial adversity. This perspective integrates neurobiological and psychosocial factors in FND and proposes a research agenda, highlighting the need for replication of existing findings, multimodal sampling across emotional response domains and further examination of emotional influences on sensorimotor and cognitive functions in FND populations.

Suicidal Ideation and Traumatic Exposure Should Not Be Neglected in Epileptic Patients: A Multidimensional Comparison of the Psychiatric Profile of Patients Suffering From Epilepsy and Patients Suffering From Psychogenic Nonepileptic Seizures

Introduction: Patients with psychogenic nonepileptic seizures (PNESs) have often been exposed to traumatic events, which is a risk factor for suicidal behavior. This would suggest that the severity of suicidal ideation is greater in PNES than in patients suffering only from epileptic seizures (ESs). However, these psychiatric symptoms may be underestimated in the ES population. The specific features or similarities between the psychiatric clinical profiles of these two groups should be elaborated to improve therapeutic management. Our study is the first to compare suicidal ideation, suicide risk, posttraumatic stress disorder (PTSD), and depression disorder simultaneously in both groups, in a tertiary care epilepsy center. Material and methods: We prospectively enrolled patients hospitalized for video-electroencephalography (EEG) monitoring to assess repeated seizures before an ES or a PNES diagnosis was made. During the psychiatric consultation that accompanied the video EEG, we rated the severity of suicidal ideation and depressive symptoms, suicidal risk, traumatic exposure history, and PTSD symptoms. Results: Eighteen subjects were enrolled and diagnosed with PNES, and 42, with ES. The PNES group reported more exposures to traumatic events and more intense PTSD symptoms (median: 17 vs. 27; p = 0.001). The severity of suicidal ideation did not differ significantly between the two groups. Conclusion: It is the severity of PTSD symptoms in PNES patients that differentiates them from ES patients, although exposure to traumatic events is also frequent in ES patients. We demonstrated that suicidal ideation and suicide risk are equally high in the ES and PNES groups. Therefore, both groups require extreme vigilance in terms of suicidal risk.

Structural alterations in functional neurological disorder and related conditions: a software and hardware problem?

Functional neurological (conversion) disorder (FND) is a condition at the interface of neurology and psychiatry. A “software” vs. “hardware” analogy describes abnormal neurobiological mechanisms occurring in the context of intact macroscopic brain structure. While useful for explanatory and treatment models, this framework may require more nuanced considerations in the context of quantitative structural neuroimaging findings in FND. Moreover, high co-occurrence of FND and somatic symptom disorders (SSD) as defined in DSM-IV (somatization disorder, somatoform pain disorder, and undifferentiated somatoform disorder; referred to as SSD for brevity in this article) raises the possibility of a partially overlapping pathophysiology. In this systematic review, we use a transdiagnostic approach to review and appraise the structural neuroimaging literature in FND and SSD. While larger sample size studies are needed for definitive characterization, this article highlights that individuals with FND and SSD may exhibit sensorimotor, prefrontal, striatal-thalamic, paralimbic, and limbic structural alterations. The structural neuroimaging literature is contextualized within the neurobiology of stress-related neuroplasticity, gender differences, psychiatric comorbidities, and the greater spectrum of functional somatic disorders. Future directions that could accelerate the characterization of the pathophysiology of FND and DSM-5 SSD are outlined, including “disease staging” discussions to contextualize subgroups with or without structural changes. Emerging neuroimaging evidence suggests that some individuals with FND and SSD may have a “software” and “hardware” problem, although if structural alterations are present the neural mechanisms of functional disorders remain distinct from lesional neurological conditions. Furthermore, it remains unclear whether structural alterations relate to predisposing vulnerabilities or consequences of the disorder.

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Transdiagnostic systematic review of structural MRI studies in FND and SSD

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Sensorimotor-striatothalamic-limbic-paralimbic circuits implicated in both conditions.

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Some small sample size FND studies did not show group-level structural alterations.

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MRI alterations may relate to risk factors, compensatory changes or disease mechanisms.

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Early-phase discussion on disease-staging algorithms outlined as a future direction.

Subjective and physiological response to emotions in temporal lobe epilepsy and psychogenic non-epileptic seizures

BACKGROUND

Temporal lobe epilepsy (TLE) and psychogenic non-epileptic seizures (PNES) are conditions frequently associated with dysfunction in emotional regulation leading to increased risk of affective disorders. This study investigates emotional processing with an objective measure of emotional reactivity in patients with TLE and patients with PNES.

METHODS

34 patients with TLE and 14 patients with PNES were evaluated on skin conductance responses (SCR) to emotions induced by short films and compared to 34 healthy controls. An attention and a suppression condition were performed while viewing the films.

RESULTS

The both groups of patients disclosed lower SCR to emotions compared to controls, mainly in suppression condition. While TLE patients had lower SCR in attention condition than controls for fear, sadness and happiness, PNES had lower SCR only for happiness. In suppression condition, both had lower SCR than controls except for peacefulness in both groups and sadness in PNES. Subjective evaluations revealed that both patient's groups scored a higher intensity for sadness than controls in attention and lower for in fear and disgust in suppression only in TLE.

LIMITATIONS

The sample size in the PNES group and the lack of a control group with similar levels of mood symptoms limited the interpretation of our results.

CONCLUSION

As no correlation were found between SCR to emotions and scores of affective disorders, this pattern of responses might be underpinned by specific pathophysiological and cognitive mechanisms related to TLE and to PNES. Thus, therapeutic approaches targeting emotional autonomic responses can be of interest in the management of these conditions.

The role of the anterior and midcingulate cortex in the neurobiology of functional neurologic disorder

Functional neurologic disorder (FND)/conversion disorder is a prevalent and disabling condition at the intersection of neurology and psychiatry. Clinicians often report feeling ill-equipped treating patients with FND, perpetuated by a historically limited understanding of neurobiologic disease mechanisms. In this review, we summarize the neuroimaging literature across the spectrum of sensorimotor FND, including functional imaging studies during rest, sensorimotor performance, and emotional-processing tasks as well as structural magnetic resonance imaging findings. Particular attention is given to studies implicating the anterior and middle cingulate cortex and related salience network structures (insula, amygdala, and periaqueductal gray) in the neurobiology of FND. Neuroimaging studies identify cingulo-insular functional alterations during rest, motor performance, and emotion processing in FND populations. The literature also supports that patients with FND exhibit heightened amygdalar and periaqueductal gray reactivity to emotionally valenced stimuli, enhanced coupling between amygdalar and motor control areas, and increased amygdalar volumes. The structural neuroimaging literature also implicates cingulo-insular areas in the pathophysiology of FND, though these findings require replication and clarification. While more research is needed to fully elucidate the pathophysiology of FND, salience network alterations appear present in some FND populations and can be contextualized using biopsychosocial models for FND.

Processing of Emotion in Functional Neurological Disorder

Emotions have traditionally been considered crucial in the development of functional neurological disorder, but the evidence underpinning this association is not clear. We aimed to summarize evidence for association between functional neurological disorder and emotions as formulated by Breuer and Freud in their conception of hysterical conversion. Based on a systematic literature search, we identified 34 controlled studies and categorized them into four groups: (i) autonomic arousal, (ii) emotion-motion interactions, (iii) social modulation of symptoms, and (iv) bodily awareness in FND. We found evidence for autonomic dysregulation in FND; convergent neuroimaging findings implicate abnormal limbic-motor interactions in response to emotional stimuli in FND. Our results do not provide enough empirical evidence for social modulation of the symptoms, but there is a clinical support for the role of suggestion and placebo in FND. Our results provide evidence for abnormal bodily awareness in FND. Based on these findings, we propose that functional neurological symptoms are forms of emotional reactions shaped into symptoms by previous experience with illness and possibly reinforced by actual social contexts. Additional research should investigate the effect of social context on the intensity of functional neurological symptoms and associated brain regions.