Functional neurological disorder: new subtypes and shared mechanisms

Connectome-based prediction of cognitive performance in patients with temporal lobe epilepsy

OBJECTIVE

Temporal lobe epilepsy (TLE) patients often exhibit varying degrees of cognitive impairments. This study aims to predict cognitive performance in TLE patients by applying a connectome-based predictive model (CPM) to whole-brain resting-state functional connectivity (RSFC) data.

METHODS

A CPM was established and leave-one-out cross-validation was employed to decode the cognitive performance of patients with TLE based on the whole-brain RSFC.

RESULTS

Our findings indicate that cognitive performance in TLE can be predicted through the internal and network connections of the parietal lobe, limbic lobe, and cerebellum systems. These systems play crucial roles in cognitive control, emotion processing, and social perception and communication, respectively. In the subgroup analysis, CPM successfully predicted TLE patients with and without focal to bilateral tonic-clonic seizures (FBCTS). Additionally, significant differences were noted between the two TLE patient groups and the normal control group.

CONCLUSION

This data-driven approach provides evidence for the potential of predicting brain features based on the inherent resting-state brain network organization. Our study offers an initial step towards an individualized prediction of cognitive performance in TLE patients, which may be beneficial for diagnosis, prognosis, and treatment planning.

Social cognition in Parkinson's disease and functional movement disorders

INTRODUCTION

Functional movement disorders (FMD) can overlap with Parkinson's disease (PD), and distinguishing between the two clinical conditions can be complex. Framing social cognition (theory of mind) (TOM) disorder, attention deficit, and psychodynamic features of FMD and PD may improve diagnosis.

METHODS

Subjects with FMD and PD and healthy controls (HC) were administered tasks assessing TOM abilities and attention. The psychodynamic hypothesis of conversion disorder was explored by a questionnaire assessing dissociative symptoms. A comprehensive battery of neuropsychological tasks was also administered to FMD and PD.

RESULTS

Although both FMD and PD scored lower than HC on all TOM tests, significant correlations between TOM and neuropsychological tasks were found only in PD but not in FMD. Only PD showed a reduction in attentional control. Dissociative symptoms occurred only in FMD.

DISCUSSION

Cognitive-affective disturbances are real in FMD, whereas they are largely dependent on cognitive impairment in PD. Attentional control is preserved in FMD compared to PD, consistent with the hypothesis that overload of voluntary attentional orientation may be at the basis of the onset of functional motor symptoms. On a psychodynamic level, the confirmation of dissociative symptoms in FMD supports the conversion disorder hypothesis.

CONCLUSION

FMD and PD can be distinguished on an affective and cognitive level. At the same time, however, the objective difficulty often encountered in distinguishing between the two pathologies draws attention to how blurred the boundary between 'organic' and 'functional' can be.

Experimental evidence for a robust, transdiagnostic marker in functional disorders: Erroneous sensorimotor processing in functional dizziness and functional movement disorder

OBJECTIVE

Recent neuroscientific models suggest that functional bodily symptoms can be attributed to perceptual dysregulation in the central nervous system. Evidence for this hypothesis comes from patients with functional dizziness, who exhibit marked sensorimotor processing deficits during eye-head movement planning and execution. Similar findings in eye-head movement planning in patients with irritable bowel syndrome confirmed that these sensorimotor processing deficits represent a shared, transdiagnostic mechanism. We now examine whether erroneous sensorimotor processing is also at play in functional movement disorder.

METHODS

We measured head movements of 10 patients with functional movement disorder (F44.4, ICD-10), 10 patients with functional dizziness (F45.8, ICD-10), and (respectively) 10 healthy controls during an eye-head experiment, where participants performed large gaze shifts under normal, increased, and again normal head moment of inertia. Head oscillations at the end of the gaze shift served as a well-established marker for sensorimotor processing problems. We calculated Bayesian statistics for comparison.

RESULTS

Patients with functional movement disorder (Bayes Factor (BF)10 = 5.36, BFincl = 11.16; substantial to strong evidence) as well as patients with functional dizziness (BF10 = 2.27, BFincl = 3.56; anecdotal to substantial evidence) showed increased head oscillations compared to healthy controls, indicating marked deficits in planning and executing movement.

CONCLUSION

We replicate earlier experimental findings on erroneous sensorimotor processing in patients with functional dizziness, and show that patients with functional movement disorder show a similar impairment of sensorimotor processing during large gaze shifts. This provides an objectively measurable, transdiagnostic marker for functional disorders, highlighting important implications for diagnosis, treatment, and de-stigmatization.

Functional Neurological Disorders Among Patients With Tremor

OBJECTIVE

Functional neurological disorders (FNDs) are increasingly recognized in the general population and neurology clinics, and there is evidence that patients with neurological disorders are more likely to have a FND. This study was designed to identify the clinical features of FNDs among patients with movement disorders when the two disorders coexist.

METHODS

The clinical histories and video recordings of 150 consecutive patients with tremors were examined: the types of tremor included essential tremor; essential tremor plus; dystonic tremor; tremor associated with dystonia; and drug-induced, myoclonic, orthostatic, task-specific, parkinsonian, Holmes, and unclassified tremor. Using criteria for "possible" and "probable" coexistent FND, clinical features that helped differentiate between functional and other neurological tremors were identified.

RESULTS

There were 27 (18%) patients with functional manifestations, and 17 (11% of full sample) of these patients had signs suggestive of comorbid functional tremor. Patients with comorbid functional manifestations were younger at presentation, and these patients had greater severity of tremor, particularly upper limb postural tremor. Functional manifestations were not more commonly observed among patients with any particular type of tremor, except for patients with Holmes tremor, who were more likely to have comorbid functional neurological manifestations.

CONCLUSIONS

About 18% of patients with diverse types of tremors also had comorbid functional neurological manifestations. Of the coexistent FNDs, functional tremor was the most common. Patients with co-occurring functional and other neurological tremors presented for evaluation at a younger age and had greater severity of arm tremor than those without comorbid functional neurological manifestations.

Machine learning classification of functional neurological disorder using structural brain MRI features

BACKGROUND

Brain imaging studies investigating grey matter in functional neurological disorder (FND) have used univariate approaches to report group-level differences compared with healthy controls (HCs). However, these findings have limited translatability because they do not differentiate patients from controls at the individual-level.

METHODS

183 participants were prospectively recruited across three groups: 61 patients with mixed FND (FND-mixed), 61 age-matched and sex-matched HCs and 61 age, sex, depression and anxiety-matched psychiatric controls (PCs). Radial basis function support vector machine classifiers with cross-validation were used to distinguish individuals with FND from HCs and PCs using 134 FreeSurfer-derived grey matter MRI features.

RESULTS

Patients with FND-mixed were differentiated from HCs with an accuracy of 0.66 (p=0.005; area under the receiving operating characteristic (AUROC)=0.74); this sample was also distinguished from PCs with an accuracy of 0.60 (p=0.038; AUROC=0.56). When focusing on the functional motor disorder subtype (FND-motor, n=46), a classifier robustly differentiated these patients from HCs (accuracy=0.72; p=0.002; AUROC=0.80). FND-motor could not be distinguished from PCs, and the functional seizures subtype (n=23) could not be classified against either control group. Important regions contributing to statistically significant multivariate classifications included the cingulate gyrus, hippocampal subfields and amygdalar nuclei. Correctly versus incorrectly classified participants did not differ across a range of tested psychometric variables.

CONCLUSIONS

These findings underscore the interconnection of brain structure and function in the pathophysiology of FND and demonstrate the feasibility of using structural MRI to classify the disorder. Out-of-sample replication and larger-scale classifier efforts incorporating psychiatric and neurological controls are needed.

The functional role of conscious sensation of movement

This paper proposes a new framework for investigating neural signals sufficient for a conscious sensation of movement and their role in motor control. We focus on signals sufficient for proprioceptive awareness, particularly from muscle spindle activation and from primary motor cortex (M1). Our review of muscle vibration studies reveals that afferent signals alone can induce conscious sensations of movement. Similarly, studies employing peripheral nerve blocks suggest that efferent signals from M1 are sufficient for sensations of movement. On this basis, we show that competing theories of motor control assign different roles to sensation of movement. According to motor command theories, sensation of movement corresponds to an estimation of the current state based on afferent signals, efferent signals, and predictions. In contrast, within active inference architectures, sensations correspond to proprioceptive predictions driven by efferent signals from M1. The focus on sensation of movement provides a way to critically compare and evaluate the two theories. Our analysis offers new insights into the functional roles of movement sensations in motor control and consciousness.

Virtual reality in functional neurological disorder: a theoretical framework and research agenda for use in the real world

Functional neurological disorder (FND) is a common and disabling condition at the intersection of neurology and psychiatry. Despite remarkable progress over recent decades, the mechanisms of FND are still poorly understood and there are limited diagnostic tools and effective treatments. One potentially promising treatment modality for FND is virtual reality (VR), which has been increasingly applied to a broad range of conditions, including neuropsychiatric disorders. FND has unique features, many of which suggest the particular relevance for, and potential efficacy of, VR in both better understanding and managing the disorder. In this review, we describe how VR might be leveraged in the treatment and diagnosis of FND (with a primary focus on motor FND and persistent perceptual-postural dizziness given their prominence in the literature), as well as the elucidation of neurocognitive mechanisms and symptom phenomenology. First, we review what has been published to date on the applications of VR in FND and related neuropsychiatric disorders. We then discuss the hypothesised mechanism(s) underlying FND, focusing on the features that are most relevant to VR applications. Finally, we discuss the potential of VR in (1) advancing mechanistic understanding, focusing specifically on sense of agency, attention and suggestibility, (2) overcoming diagnostic challenges and (3) developing novel treatment modalities. This review aims to develop a theoretical foundation and research agenda for the use of VR in FND that might be applicable or adaptable to other related disorders.

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.

Exploring therapeutic interventions for functional neurological disorders: a comprehensive scoping review

Functional Neurological Disorders (FNDs) are characterized by the symptoms experienced by the individuals but also by how they express personal experiences and concerns related to the clinical condition. Access to care programs for functional neurological symptoms appears challenging and may entail circular, self-perpetuating healthcare pathways. Given the challenging and misleading interpretations around FND, in advocating for care pathways beyond medical therapies, we designed a scoping review to map recently suggested practices and interventions. We identified 31 relevant papers published between January 2018 and December 2022. Most of the literature was gathered from the US and UK healthcare experiences, with documented interventions provided by multi-professional teams or stand-alone psychotherapists. We found different care pathways addressing either motor or non-motor manifestations. Persons with Functional Motor Disorder are more likely to be referred to physical therapy first, while Persons suffering from Non-Epileptic Seizures are to mental health services. A narrow focus was given to minor components of multimodal approaches (e.g. social workers, and occupational therapists). High heterogeneity was found between assessment instruments as well, reflecting different perspectives in selecting treatment outcomes (e.g., reduction of non-epileptic events, psychological functioning, motor symptoms). Among healthcare professionals, neurologists and (neuro)psychiatrists are typically engaged in formulating and delivering diagnoses, while treatment is often administered by physiotherapists and/or psychologists. In the context of FNDs, the complex etiopathological nature of the condition, including comorbidities, suggests the recommendation of multidisciplinary treatments adopting a stepped care model progressing from standard to higher level individualized modules may better suit individual complexities.

Psychological Therapy for Functional Neurological Disorder: Examining Impact on Dissociation, Psychological Distress and General Functioning

Functional neurological disorder (FND) represents a broad group of motor and sensory clinical symptoms which cannot be explained by other neurological diagnoses. Dissociation is considered a key mechanism in their development and maintenance. Despite psychological therapy being the recommended choice of treatment for FND, evidence for its effectiveness is in its infancy. This study explored the dissociative profile of forty-seven patients with FND and evaluated whether individual psychological therapy improved dissociative symptoms, psychological distress and general functioning among twenty-five adults with FND. Patients completed the Multiscale Dissociation Inventory, the EuroQol five-dimensional descriptive system, the General Anxiety Disorder-7 scale and the Patient Health Questionnaire-9. Our sample showed high levels of disengagement, depersonalization and memory disturbance at baseline. Treatment was associated with significant improvements in general functioning, and symptoms of dissociation and anxiety. Improvements in dissociative experiences were found to be possibly due to reduction in anxiety. Improvements in depression were the strongest predictor of improvements in general functioning. Limitations and areas for further research are discussed.

Misdiagnosis of functional neurological symptom disorders in paediatrics: Narrative review and relevant case report

Functional neurological symptom disorders (FNSD) pose a common challenge in clinical practice, particularly in pediatric cases where the clinical phenotypes can be intricate and easily confused with structural disturbances. The frequent coexistence of FNSDs with other medical disorders often results in misdiagnosis. In this review, we highlight the distinctions between FNSD and various psychiatric and neurological conditions. Contrary to the misconception that FNSD is a diagnosis of exclusion, we underscore its nature as a diagnosis of inclusion, contingent upon recognizing specific clinical features. However, our focus is on a critical learning point illustrated by the case of a 14-year-old male initially diagnosed with FNSD, but subsequently found to have a rare primary monogenic movement disorder (paroxysmal kinesigenic dyskinesia, PKD). The crucial takeaway from this case is the importance of avoiding an FNSD diagnosis based solely on psychiatric comorbidity and suppressible symptoms. Instead, clinicians should diligently assess for specific features indicative of FNSD, which were absent in this case. This emphasizes the importance of making a diagnosis of inclusion. Extended follow-up and clinical-oriented genetic testing might help identify comorbidities, prevent misdiagnosis, and guide interventions in complex cases, which cannot be simply classified as "functional" solely because other conditions can be excluded.

Stigma in functional neurological disorder (FND) - A systematic review

OBJECTIVE

The purpose of this systematic review was to evaluate stigma and Functional Neurological Disorder (FND) regarding: 1) prevalence and associated factors, 2) the nature and context of stigma in FND, and 3) stigma-reduction interventions.

METHODS

We searched four relevant databases from inception to December 2023, using search terms relevant to FND and stigma themes. We employed the method of synthesis by "aggregation and configuration" to synthesise and analyse the data into emergent themes.

RESULTS

We found 127 studies, spanning 148 countries, involving 18,886 participants. Of these, 4889 were patients, 13,123 were healthcare professionals, and 526 were caregivers. Quantitatively, stigma has been mainly studied in patients with functional seizures, and was higher than patients with epilepsy in three studies. Stigma experienced by patients is associated with poorer quality of life and caregiver burden. We found 10 themes and 29 subthemes revealing stigma as a systemic process, with intrapersonal, interpersonal and structural aspects. Few studies examined the perspective of caregivers, the public or online community. We identified six anti-stigma interventions.

CONCLUSION

Stigma in FND is a layered process, and affects patient quality of life and provision of care. Stigma needs to be addressed from the top structures, at governmental level, so that appropriate care pathways can be created, giving patients with FND parity of esteem with other medical conditions.

Optimizing outcomes when treating functional neurological disorder in acute care settings: case reports depicting the value of diagnostic precision and timely and appropriate psychological interventions using an interdisciplinary framework

Introduction

Unexplained physical signs and symptoms represent a significant portion of patient presentations in acute care settings. Even in cases where a patient presents with a known medical condition, functional or somatic symptoms may complicate the diagnostic and treatment processes and prognostic outcome. One umbrella category for neurologically related somatic symptoms, functional neurological disorder (FND), presents as involuntary neurological symptoms incompatible with another medical condition. Symptoms may include weakness and/or paralysis, movement disorders, non-epileptic seizures, speech or visual impairment, swallowing difficulty, sensory disturbances, or cognitive symptoms (1). While FND presents as neuropsychiatric, providers commonly report feeling hesitant to diagnose these disorders. Inexperience or lack of appropriate education on relevant research regarding evidence-based practices or standard of practice (SOP) may result in over- or underperforming diagnostic workups and consultations, utilizing inappropriate medications, and failing to offer evidence-based psychological interventions. Being mindful of these challenges when treating patients presenting with functional symptoms in acute care settings can help to support and protect the patients and care team and appropriately control healthcare costs.

Methods

The University of Alabama at Birmingham Medical Center identified cases representing categories of quality and safety problems that arise in treating FND in acute care settings. Patients signed a consent form to participate in the case report. The case information for each was presented without identifying information.

Discussion

The cases highlight potential challenges when caring for patients presenting with FND in acute care settings. The challenges covered include over- or underutilization of diagnostic workups and consultation, over- or underutilization of psychopharmacological medications, and over- or undertreating a medical condition when a functional symptom is present. In each case, these lapses and errors caused the patient distress, additional treatments, care delays, and delayed symptom remission. Additionally, these challenges have direct and indirect fiscal costs, which can be mitigated with the appropriate education and training, resources, and protocols. Hospitals can benefit from system-wide SOP to improve the identification and management of FND to prevent harm to patients. An SOP commonly presents to specific specialties and ensures the appropriate diagnostic workup, consultations, and timely evidence-based interventions.

[Interpretation of a concept for functional movement disorders from the perspective of older patients]

A recently published concept considers a significant proportion of the occurrence and persistence of functional movement disorders (FMD) to be explained by increased/incorrect weighting of the expected movement (feedforward signal) in the presence of decreased/altered actual feedback of the movement. In the context of aging and age-associated diseases, there is an increased likelihood that these prerequisites will occur, also in combination. For example, the feedforward signal can be enhanced by accumulation of a wealth of experience but can for example become prone to error due to changes in attention and (fear of) falling. Conversely, the actual feedback is subject to age-related changes, such as reduction of sensory functions. This could explain why FMDs also occur in old age and offer treatment approaches for this so far poorly studied disorder. It follows that a specific focus on (the correction of) feedforward signals and strengthening as well as training of the actual feedback are potentially promising therapeutic approaches for older people with FMD.

Sensory Processing Difficulties and Occupational Therapy Outcomes for Functional Neurological Disorder: A Retrospective Cohort Study

Background and Objectives

Occupational therapy (OT) consensus recommendations and articles outlining a sensory-based OT intervention for functional neurological disorder (FND) have been published. However, limited research has been conducted to examine the efficacy of OT interventions for FND. We performed a retrospective cohort study aimed at independently replicating preliminarily characterized sensory processing difficulties in patients with FND and reporting on clinical outcomes of a sensory-based OT treatment in this population. We hypothesized that (1) a history of functional seizures, anxiety, and/or post-traumatic stress disorder would be associated with increased sensory processing difficulties and (2) the number of OT treatment sessions received would positively relate to clinical improvement.

Methods

Medical records were reviewed for 77 consecutive adults with FND who received outpatient, sensory-based OT care. Data from the Adolescent/Adult Sensory Profile characterized self-reported sensory processing patterns across 4 quadrants (low registration, sensory sensitivity, sensory seeking, and sensory avoidance) in this population. Following univariate screenings, multivariate linear regression analyses were performed to identify neuropsychiatric characteristics associated with discrete sensory processing patterns. Clinical improvement was quantified using an estimated, clinician-determined improvement rating ("improved" vs "not improved"), and relationships between clinical participation, baseline neuropsychiatric factors, and outcomes were investigated.

Results

Patients with FND reported sensory processing patterns with elevated scores in low registration, sensory sensitivity, and sensation avoidance compared with normative values; differences in sensory processing scores were not observed across FND subtypes (i.e., motor, seizure, and speech variants). In linear regression analyses, lifetime history of an anxiety disorder, history of migraine headaches, current cognitive complaints, and a comorbid major neurologic condition independently predicted individual differences in sensory processing scores. Following a sensory-based OT intervention, 62% of individuals with FND were clinician determined as "improved." In a multivariate logistic regression analysis controlling for baseline characteristics associated with improvement ratings, number of treatment sessions positively correlated with clinical improvement.

Discussion

These findings support the presence of sensory processing difficulties in patients with FND and provide Class IV evidence for the efficacy of an outpatient, sensory-based OT intervention in this population. Controlled prospective trials are warranted.

Persistent postural-perceptual dizziness: A functional neuro-otologic disorder

Persistent postural-perceptual dizziness (PPPD) is a functional neuro-otologic disorder that is the most frequent cause of chronic vestibular syndrome. The core vestibular symptoms include dizziness, unsteadiness, and non-spinning vertigo, which are exacerbated by an upright posture or walking, active or passive motion, and exposure to moving or complex visual stimuli. PPPD is mostly precipitated by acute or episodic vestibular diseases; however, its symptoms cannot be accounted for by its precipitants. PPPD is not a diagnosis of exclusion, but may coexist with other structural diseases. Thus, when diagnosing PPPD, the patient's symptoms must be explained by PPPD alone or by PPPD in combination with a structural illness. PPPD is most frequently observed at approximately 50 years of age, with a female predominance. Conventional vestibular tests do not reveal any specific signs of PPPD. However, the head roll-tilt subjective visual vertical test and gaze stability test after exposure to moving visual stimuli may detect the characteristic features of PPPD, that is, somatosensory- and visually-dependent spatial orientation, respectively. Therefore, these tests could be used as diagnostic tools for PPPD. Regarding the pathophysiology of PPPD, neuroimaging studies suggest shifts in interactions among visuo-vestibular, sensorimotor, and emotional networks, where visual inputs dominate over vestibular inputs. Postural control also shifts, leading to the stiffening of the lower body. To treat PPPD, selective serotonin reuptake inhibitors/serotonin noradrenaline reuptake inhibitors, vestibular rehabilitation, and cognitive behavioral therapy are used alone or in combination.

How stigma unfolds for patients with Functional Neurological Disorder

OBJECTIVE

The aim of this study was to explore experiences of stigma in Functional Neurological Disorder (FND) from the perspective of the patient as it manifests from the onset of symptoms, up to diagnosis and subsequently.

BACKGROUND

The existing literature clearly shows that stigma exists for many patients with FND, and is associated with poorer quality of life. However, it is less clear how stigma unfolds, and how it can be alleviated.

METHODS

We performed a qualitative interview study with patients who were diagnosed with FND, using data based on semi-structured interviews. Participants were recruited purposively via outpatient clinics. We analysed the data using a reflexive thematic analytic approach, through the lens of recognised stigma frameworks.

RESULTS

15 participants were included in the study, aged between 19 and 68 years, with varying presentations of FND. We identified six themes and 16 subthemes relevant to their stigma trajectory. We found that stigma unfolds through four main domains: 1) through their symptom experience; 2) through "othering" by the healthcare system; 3) through everyday interactions; and 4) from within the self. Across these four domains was a central theme of 5) stages of knowledge, which both fuelled and countered stigma. Lastly, 6) validation of the patient experience emerged as a theme that alleviated stigma.

CONCLUSIONS

Stigma did not unfold as a linear process, rather it came from multiple interacting sources. Interventions to target stigma could take the form of improved clinician training, communication, especially around point of diagnosis, and public interventions, co-produced with patients with FND.

Promoting Growth in Behavioral Neurology: A Path Forward

Behavioral neurology & neuropsychiatry (BNNP) is a field that seeks to understand brain-behavior relationships, including fundamental brain organization principles and the many ways that brain structures and connectivity can be disrupted, leading to abnormalities of behavior, cognition, emotion, perception, and social cognition. In North America, BNNP has existed as an integrated subspecialty through the United Council for Neurologic Subspecialties since 2006. Nonetheless, the number of behavioral neurologists across academic medical centers and community settings is not keeping pace with increasing clinical and research demand. In this commentary, we provide a brief history of BNNP followed by an outline of the current challenges and opportunities for BNNP from the behavioral neurologist's perspective across clinical, research, and educational spheres. We provide a practical guide for promoting BNNP and addressing the shortage of behavioral neurologists to facilitate the continued growth and development of the subspecialty. We also urge a greater commitment to recruit trainees from diverse backgrounds so as to dismantle persistent obstacles that hinder inclusivity in BNNP-efforts that will further enhance the growth and impact of the subspecialty. With rapidly expanding diagnostic and therapeutic approaches across a range of conditions at the intersection of neurology and psychiatry, BNNP is well positioned to attract new trainees and expand its reach across clinical, research, and educational activities.

The role of neuropsychology in the care of patients with functional neurological symptom disorder

OBJECTIVE

Functional neurological symptom disorder (FNSD) is a neuropsychiatric condition characterized by signs/symptoms associated with brain network dysfunction. FNSDs are common and are associated with high healthcare costs. FNSDs are relevant to neuropsychologists, as they frequently present with chronic neuropsychiatric symptoms, subjective cognitive concerns, and/or low neuropsychological test scores, with associated disability and reduced quality of life. However, neuropsychologists in some settings are not involved in care of patients with FNSDs. This review summarizes relevant FNSD literature with a focus on the role of neuropsychologists.

METHODS

A brief review of the literature is provided with respect to epidemiology, public health impact, symptomatology, pathophysiology, and treatment.

RESULTS

Two primary areas of focus for this review are the following: (1) increasing neuropsychologists' training in FNSDs, and (2) increasing neuropsychologists' role in assessment and treatment of FNSD patients.

CONCLUSIONS

Patients with FNSD would benefit from increased involvement of neuropsychologists in their care.

How do I manage functional visual loss

Functional visual loss is a subtype of functional neurological disorder (FND) and is a common cause of visual impairment seen in both general and neuro-ophthalmological practice. Ophthalmologists can generally diagnose functional visual loss reasonably confidently but often find it harder to know what to say to the patient, how to approach, or even whether to attempt, treatment. There is little evidence-based treatment despite studies showing up to 60% of adults having impactful symptoms on long-term follow-up. The last 20 years has seen large changes in how we understand, approach, and manage FND more widely. In this article, we set out our practical approach to managing functional visual loss which includes : 1) Make a positive diagnosis based on investigations that demonstrate normal vision in the presence of subjectively impaired vision, not just because tests or ocular exam is normal; 2) Explain and label the condition with an emphasis on these positive diagnostic features, not reassurance; 3) Consider eye or brain comorbidities such as migraine, idiopathic intracranial hypertension or amblyopia; 4) Consider working with an orthoptist using diagnostic tests in a positive way to highlight the possibility of better vision; 5) Develop simple treatment strategies for photophobia; 6) Consider psychological factors and comorbidity as part of assessment and therapy, but keep a broader view of aetiology and don't use this to make a diagnosis; 7) Other treatment modalities including hypnotherapy, transcranial magnetic stimulation and more advanced forms of visual feedback are promising candidates for functional visual loss treatment in the 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.

Personality and psychopathological characteristics in functional movement disorders

INTRODUCTION

Aim of the present study was to assess personality and psychopathological characteristics in patients with functional movement disorders (FMDs) compared to patients with other neurological disorders (OND).

METHODS

In this cross-sectional study, patients affected by clinically established FMDs and OND who attended the Neurologic Unit of the University-Hospital "Policlinico-San Marco" of Catania from the 1st of December 2021 to the 1st of June 2023 were enrolled. Personality characteristics were assessed with the Rorschach test coded according to Exner's comprehensive system and the Structured Clinical Interview for DSM-5 (SCID-II).

RESULTS

Thirty-one patients with FMDs (27 women; age 40.2±15.5 years; education 11.7±3.2 years; disease duration 2.3±2.5 years) and 24 patients affected by OND (18 women; age 35.8±16.3 years; education 11.9±2.9 years; disease duration 3.4±2.8 years) were enrolled. At the Rorschach, FMDs presented a significantly higher frequency of Popular (P) and sum of all Human content codes (SumH>5) responses and avoidant coping than OND.

CONCLUSION

FMDs presented "conformity behaviors", excessive interest in others than usual a maladaptive avoidant style of coping and a difficulty in verbalizing emotional distress. These psychopathological characteristics may favor the occurrence of FMDs.

Functional Neurological Disorder Presenting After Concussion: A Retrospective Case Series

OBJECTIVE

Although a majority of individuals recover from a concussion within weeks of the index injury, a substantial minority of patients report persistent postconcussion symptoms. Some of these symptoms may reflect a diagnosis of functional neurological disorder (FND). The authors evaluated the relationship between persistent postconcussion symptoms and FND symptoms.

METHODS

In this retrospective chart review, the authors characterized demographic and clinical information from 50 patients with a confirmed diagnosis of FND whose functional neurological symptoms started after a concussion.

RESULTS

Patients who developed FND after a concussion had high rates of baseline risk factors for both persistent postconcussion symptoms and FND. After the concussive event, functional neurological symptoms presented abruptly or developed insidiously over time. Functional neurological symptoms ranged widely and included gait symptoms, seizures, speech and language symptoms, weakness, sensory symptoms, tremors, and vision and oculomotor symptoms.

CONCLUSIONS

Functional neurological symptoms can arise after a concussion. FND should be considered in the differential diagnosis of individuals presenting with neurological symptoms beginning after a concussion. By failing to recognize functional symptoms, clinicians may inadvertently reinforce negative health-related beliefs regarding a patient's injured brain.

Perspectives on the diagnosis and management of functional cognitive disorder: An international Delphi study

BACKGROUND

Current proposed criteria for functional cognitive disorder (FCD) have not been externally validated. We sought to analyse the current perspectives of cognitive specialists in the diagnosis and management of FCD in comparison with neurodegenerative conditions.

METHODS

International experts in cognitive disorders were invited to assess seven illustrative clinical vignettes containing history and bedside characteristics alone. Participants assigned a probable diagnosis and selected the appropriate investigation and treatment. Qualitative, quantitative and inter-rater agreement analyses were undertaken.

RESULTS

Eighteen diagnostic terminologies were assigned by 45 cognitive experts from 12 countries with a median of 13 years of experience, across the seven scenarios. Accurate discrimination between FCD and neurodegeneration was observed, independently of background and years of experience: 100% of the neurodegenerative vignettes were correctly classified and 75%-88% of the FCD diagnoses were attributed to non-neurodegenerative causes. There was <50% agreement in the terminology used for FCD, in comparison with 87%-92% agreement for neurodegenerative syndromes. Blood tests and neuropsychological evaluation were the leading diagnostic modalities for FCD. Diagnostic communication, psychotherapy and psychiatry referral were the main suggested management strategies in FCD.

CONCLUSIONS

Our study demonstrates the feasibility of distinguishing between FCD and neurodegeneration based on relevant patient characteristics and history details. These characteristics need further validation and operationalisation. Heterogeneous labelling and framing pose clinical and research challenges reflecting a lack of agreement in the field. Careful consideration of FCD diagnosis is advised, particularly in the presence of comorbidities. This study informs future research on diagnostic tools and evidence-based interventions.

A new perspective on positive symptoms: expression of damage or self-defence mechanism of the brain?

Usually, positive neurological symptoms are considered as the consequence of a mere, afinalistic and abnormal increase in function of specific brain areas. However, according to the Theory of Active Inference, which argues that action and perception constitute a loop that updates expectations according to a Bayesian model, the brain is rather an explorer that formulates hypotheses and tests them to assess the correspondence between internal models and reality. Moreover, the cerebral cortex is characterised by a continuous "conflict" between different brain areas, which constantly attempt to expand in order to acquire more of the limited available computational resources, by means of their dopamine-induced neuroplasticity. Thus, it has recently been suggested that dreams, during rapid eye movement sleep (REMS), protect visual brain areas (deprived of their stimuli during rest) from being conquered by other normally stimulated ones. It is therefore conceivable that positive symptoms also have a functional importance for the brain. We evaluate supporting literature data of a 'defensive' role of positive symptoms and the relevance of dopamine-induced neuroplasticity in the context of neurodegenerative and psychiatric diseases. Furthermore, the possible functional significance of idiopathic REMS-related behavioural disorder as well as phantom limb syndrome is examined. We suggest that positive neurological symptoms are not merely a passive expression of a damage, but active efforts, related to dopamine-induced plasticity, to maintain a correct relationship between the external world and its brain representation, thus preventing healthy cortical areas from ousting injured ones.

When Nerves Tell a Different Story: Functional Neurological Disorder (FND) After a Minor Hand Injury

Hand injuries typically present with localized symptoms. However, we report an unusual case of a 32-year-old female who experienced a transient complete loss of sensation and motor function in her entire left nondominant hand after sustaining a minor 1 cm stab wound between the third and fourth metacarpals. Wound exploration under local anesthesia revealed no tendon, vascular, neural, or bony injury. Remarkably, she spontaneously regained full hand sensation and function within 120 minutes of the injury. Extensive neurological evaluation, including magnetic resonance imaging (MRI), electromyography (EMG), nerve conduction studies (NCS), and somatosensory evoked potentials (SSEPs), ruled out organic pathology and supported a diagnosis of functional neurological disorder (FND), specifically functional movement disorder (FMD). Close collaboration between hand surgeons, neurologists, and occupational therapists is essential for accurate diagnosis and appropriate multidisciplinary management. Further research is needed to elucidate the mechanisms underlying FND and optimize evidence-based treatment for FND in the context of hand trauma. The increased awareness of this condition across specialties involved in hand injury management is crucial to facilitate timely diagnosis and avoid unnecessary interventions.

Exploring psychedelic-assisted therapy in the treatment of functional seizures: A review of underlying mechanisms and associated brain networks

Functional seizures (FS), the most common subtype of functional neurological disorder (FND), cause serious neurological disability and significantly impact quality of life. Characterized by episodic disturbances of functioning that resemble epileptic seizures, FS coincide with multiple comorbidities and are treated poorly by existing approaches. Novel treatment approaches are sorely needed. Notably, mounting evidence supports the safety and efficacy of psychedelic-assisted therapy (PAT) for several psychiatric conditions, motivating investigations into whether this efficacy also extends to neurological disorders. Here, we synthesize past empirical findings and frameworks to construct a biopsychosocial mechanistic argument for the potential of PAT as a treatment for FS. In doing so, we highlight FS as a well-defined cohort to further understand the large-scale neural mechanisms underpinning PAT. Our synthesis is guided by a complexity science perspective which we contend can afford unique mechanistic insight into both FS and PAT, as well as help bridge these two domains. We also leverage this perspective to propose a novel analytic roadmap to identify markers of FS diagnostic specificity and treatment success. This endeavor continues the effort to bridge clinical neurology with psychedelic medicine and helps pave the way for a new field of psychedelic neurology.

Recent advances in understanding the neurobiology of pediatric functional neurological disorder

INTRODUCTION

Functional neurological disorder (FND) is a neuropsychiatric disorder that manifests in a broad array of functional motor, sensory, or cognitive symptoms, which arise from complex interactions between brain, mind, body, and context. Children with FND make up 10%-20% of presentations to neurology services in children's hospitals and up to 20% of adolescents admitted to hospital for the management of intractable seizures.

AREAS COVERED

The current review focuses on the neurobiology of pediatric FND. The authors present an overview of the small but growing body of research pertaining to the biological, emotion-processing, cognitive, mental health, physical health, and social system levels.

EXPERT OPINION

Emerging research suggests that pediatric FND is underpinned by aberrant changes within and between neuron-glial (brain) networks, with a variety of factors - on multiple system levels - contributing to brain network changes. In pediatric practice, adverse childhood experiences (ACEs) are commonly reported, and activation or dysregulation of stress-system components is a frequent finding. Our growing understanding of the neurobiology of pediatric FND has yielded important flow-on effects for assessing and diagnosing FND, for developing targeted treatment interventions, and for improving the treatment outcomes of children and adolescents with FND.

"This is real", "this is hard" and "I'm not making it up": Experience of diagnosis and living with non-epileptic attack disorder

PURPOSE

To use a qualitative research approach to explore adults' experience of living with non-epileptic attack disorder.

OBJECTIVE

The objective was to explore the experience of adults (18 years+) with a confirmed diagnosis of non-epileptic attack disorder (NEAD) across the trajectory of the disorder. The topics investigated included the onset of symptoms, the experience of non-epileptic attacks, the diagnostic process and living with NEAD.

METHOD

Twelve people diagnosed with NEAD who attended a tertiary hospital neurology department took part in semi-structured interviews. The data generated were analysed using reflexive thematic analysis.

RESULTS

Eleven women and one man with median age of 25 years took part. Three themes were developed: mind-body (dis)connect, a stigmatised diagnosis and a role for containment. Adults spoke about their experience of nonepileptic attacks, the diagnostic and management process and the impact of both nonepileptic attacks and the NEAD diagnosis on their lives.

CONCLUSIONS

Adults' experience's within the healthcare system across the trajectory of NEAD influenced their own understanding and trust in their NEAD experience, how they shared this with others in their social and work lives and how they managed their NEAD symptoms on a daily basis. The research suggests the need for a consistent, timely implementation of a rule-in diagnostic approach and multi-disciplinary management of NEAD. It is recommended that lessons be taken from theoretical models including the common-sense model and a modified version of the reattribution model to support the de-stigmatisation of this diagnosis to inform psychoeducation and professionally facilitated peer-support groups.

Understanding Functional Neurological Disorder: Recent Insights and Diagnostic Challenges

Functional neurological disorder (FND), formerly called conversion disorder, is a condition characterized by neurological symptoms that lack an identifiable organic purpose. These signs, which can consist of motor, sensory, or cognitive disturbances, are not deliberately produced and often vary in severity. Its diagnosis is predicated on clinical evaluation and the exclusion of other medical or psychiatric situations. Its treatment typically involves a multidisciplinary technique addressing each of the neurological symptoms and underlying psychological factors via a mixture of medical management, psychotherapy, and supportive interventions. Recent advances in neuroimaging and a deeper exploration of its epidemiology, pathophysiology, and clinical presentation have shed new light on this disorder. This paper synthesizes the current knowledge on FND, focusing on its epidemiology and underlying mechanisms, neuroimaging insights, and the differentiation of FND from feigning or malingering. This review highlights the phenotypic heterogeneity of FND and the diagnostic challenges it presents. It also discusses the significant role of neuroimaging in unraveling the complex neural underpinnings of FND and its potential in predicting treatment response. This paper underscores the importance of a nuanced understanding of FND in informing clinical practice and guiding future research. With advancements in neuroimaging techniques and growing recognition of the disorder's multifaceted nature, the paper suggests a promising trajectory toward more effective, personalized treatment strategies and a better overall understanding of the disorder.

Self-reported anterograde memory loss in older persons that is not validated on neuropsychological assessment: Considerations for a dissociative diagnosis

The past decade has witnessed amplified public awareness of age-related dementias. This has resulted in a dramatic rise in the number of older persons referred to memory clinics with a primary complaint of self-reported memory loss without an antecedent neurological event (e.g., stroke) who produce neuropsychological test profiles that lack evidence of such impairment. Since the latter part of the 19th century, a confusing array of changing terminology, criteria, and perceived causation have been ascribed to patients with unverified medical symptoms to implicate psychological causation. Such terms are often misperceived by laypersons as reflecting character flaws or malingering. Of import for clinical neuropsychologists, the 11th edition of the International Classification of Diseases added cognitive to symptoms eligible for a diagnosis of the modern formulation, dissociative neurological symptom disorder. One dissociative option for referrals with self-reported neurocognitive symptoms not validated on neuropsychological testing is functional memory disorder, conceived as a psychological disorder where emotional distress is plausibly related to the perceived memory loss but is of less severity than would warrant a major depressive or anxiety diagnosis. If evidence of psychological distress or behavioral impairment is not present the referral likely reflects the increased public awareness of age-related dementias interacting with the high base rate of self-perceived memory loss in the general population. In such cases, a dissociative diagnosis should be avoided as there is evidence of neither a medical nor a psychological disorder. A summary statement of not dementia or similar is likely sufficient to help the patient.

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.

The blink reflex and its modulation - Part 2: Pathophysiology and clinical utility

The blink reflex (BR) is integrated at the brainstem; however, it is modulated by inputs from various structures such as the striatum, globus pallidus, substantia nigra, and nucleus raphe magnus but also from afferent input from the peripheral nervous system. Therefore, it provides information about the pathophysiology of numerous peripheral and central nervous system disorders. The BR is a valuable tool for studying the integrity of the trigemino-facial system, the relevant brainstem nuclei, and circuits. At the same time, some neurophysiological techniques applying the BR may indicate abnormalities involving structures rostral to the brainstem that modulate or control the BR circuits. This is a state-of-the-art review of the clinical application of BR modulation; physiology is reviewed in part 1. In this review, we aim to present the role of the BR and techniques related to its modulation in understanding pathophysiological mechanisms of motor control and pain disorders, in which these techniques are diagnostically helpful. Furthermore, some BR techniques may have a predictive value or serve as a basis for follow-up evaluation. BR testing may benefit in the diagnosis of hemifacial spasm, dystonia, functional movement disorders, migraine, orofacial pain, and psychiatric disorders. Although the abnormalities in the integrity of the BR pathway itself may provide information about trigeminal or facial nerve disorders, alterations in BR excitability are found in several disease conditions. BR excitability studies are suitable for understanding the common pathophysiological mechanisms behind various clinical entities, elucidating alterations in top-down inhibitory systems, and allowing for follow-up and quantitation of many neurological syndromes.

Increased risk of functional neurological disorders following SARS-CoV-2 vaccination

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the possible correlation between SARS-CoV-2 vaccines and the onset of neurological syndromes. The aim was to challenge the association between SARS-CoV-2 vaccinations and the onset of acute functional neurological disorders (FNDs) compared to other neurological syndromes in hospitalized patients.

METHODS

In this prospective cohort study, all adult inpatients consecutively admitted to a tertiary neurological centre were included. The prevalence and characteristics of neurological syndromes were compared between unvaccinated and vaccinated cases stratified according to the onset from vaccination. The study involved 843 subjects, namely 411 unvaccinated (UVC) and 432 vaccinated cases; these groups were comparable for demographics and clinical diagnosis distribution.

RESULTS

Compared to UVC, subjects hospitalized within the first 30 days from vaccine exhibited higher prevalence of FNDs (12.3% vs. 3.6%; odds ratio 4.2, 95% confidence interval 1.6-11.1) and headache (10.8% vs. 5%; odds ratio 4.1, 95% confidence interval 1.9-8.8) but no other neurological syndromes. The FND cases following vaccinations showed similar premorbid conditions and severity but a higher percentage of sensory symptoms and pain compared to UVC FND cases.

CONCLUSIONS

SARS-CoV-2 vaccination is associated with a significant short-term increased risk of FND and headache requiring hospitalization in an acute neurological setting.

An update on psychogenic nonepileptic seizures

PURPOSE OF REVIEW

The understanding of psychogenic nonepileptic seizures (PNES) has advanced steadily over recent decades. This update summarizes new insights from the last three years.

RECENT FINDINGS

The process of diagnosing PNES has shifted from the exclusion of epilepsy to one based on the recognition of typical clinical features. While the diagnosis cannot rely on any single feature in isolation, a range of semiological features characterising PNES are now recognised and a number of studies hint at the potential for machine learning and AI to improve the diagnostic process. Advances in data processing and analysis may also help to make sense of the heterogeneity of PNES populations demonstrated by recent studies focussing on aetiology and patient subgroups. It is now clear that PNES are associated with high rates of mental and physical comorbidities and premature death, highlighting that they are only one manifestation of a complex disorder extending beyond the nervous system and the seizures themselves.

SUMMARY

PNES are now understood as a manifestation of dysfunction in interacting brain networks. This understanding provides an explanation for the psychopathological and semiological heterogeneity of PNES patient populations. New insights into medical comorbidities and increased rates of premature death call for more research into associated pathological processes outside the nervous system.

Characteristics and outcomes of youth with functional seizures attending intensive interdisciplinary pain treatment

Functional seizures (FS) can be debilitating and negatively impact quality of life. Yet intervention research for FS is limited, especially for youth. This study examined clinical characteristics and outcomes of youth with FS (13-23 years) presenting to a pediatric intensive interdisciplinary pain treatment (IIPT) program in the midwestern United States. Sixty youth (mean age = 16.5 years; 83.3 % female) met inclusion criteria. At intake, comorbid chronic pain, somatic symptoms, autonomic dysfunction, eating and weight disturbances, and mental health concerns were common. Despite this high symptom burden, youth with FS reported significant improvements in functioning measured with the Functional Disability Inventory, t(53) = 9.80, p <.001, d = 1.32; depression measured with the Center for Epidemiological Studies - Depression Scale for Children, t(53) = 6.76, p <.001, d = 0.91; anxiety measured with the Spence Children's Anxiety Scale, t(53) = 3.97, p < .001, d = 0.53; and catastrophizing measured with the Pain Catastrophizing Scale for Children, t(53) = 6.44, p <.001, d = 0.86, following completion of the program, suggesting that IIPT may be an effective treatment option for highly disabled and emotionally distressed youth with FS. Future research is needed to continue to refine best practices for youth with FS to reduce suffering and improve outcomes.

Prevalence of autoimmune diseases in functional neurological disorder: influence of psychiatric comorbidities and biological sex

BACKGROUND

Functional neurological disorder (FND) is a common and disabling neuropsychiatric condition, which disproportionally affects women compared with men. While the etiopathogenesis of this disorder remains elusive, immune dysregulation is emerging as one potential mechanism. To begin to understand the role of immune dysfunctions in FND, we assessed the prevalence of several common autoimmune diseases (ADs) in a large cohort of patients with FND and examined the influence of psychiatric comorbidities and biological sex.

METHODS

Using a large biorepository database (Mass General Brigham Biobank), we obtained demographic and clinical data of a cohort of 643 patients diagnosed with FND between January 2015 and December 2021. The proportion of ADs was calculated overall, by sex and by the presence of psychiatric comorbidities.

RESULTS

The overall prevalence of ADs in our sample was 41.9%, with connective tissue and autoimmune endocrine diseases being the most commonly observed ADs. Among patients with FND and ADs, 27.7% had ≥2 ADs and 8% met criteria for multiple autoimmune syndrome. Rates of ADs were significantly higher in subjects with comorbid major depressive disorder and post-traumatic stress disorder (p= 0.02). Women represented the largest proportion of patients with concurrent ADs, both in the overall sample and in the subgroups of interest (p's < 0.05).

CONCLUSIONS

This study is unique in providing evidence of an association between FND and ADs. Future studies are needed to investigate the mechanisms underlying this association and to understand whether FND is characterised by distinct dysregulations in immune response.

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.

Similarities and Differences in Functional Movement Disorders and Functional Seizures at a Tertiary Care Center: A Prospective Study

Background

Functional movement disorders (FMDs) and functional seizure (FS) are the two most important subcategories of functional neurologic disorders (FNDs).

Objectives

This study aimed to discern similarities and differences between patients with FMD and FS.

Methods

A prospective comparative study of 94 patients with FNDs (FMD = 47, FS = 47) was conducted.

Results

Tremor and pauci-kinetic attack with preserved responsiveness were the most common subtypes observed in patients with FMD and FS, respectively. A significantly higher number of patients with FMD had more than one precipitating factor (P = 0.03). Headache was significantly more common in patients with FS (P = 0.03). More patients came for follow-up in the FMD group (P = 0.01). More patients in the FS group reported "very much improvement" (P = 0.04), and "no change" was more commonly reported by the FMD group patients (P = 0.009).

Conclusion

Emotional stress was the most common precipitating factor in patients with FMD and FS. The prognosis was better in patients with FS.

Longitudinal Comparison of PNES spell and ASM reduction in PNES Patients with and without Epilepsy Discharged from an Epilepsy Monitoring Unit

OBJECTIVE

To examine trends of Antiseizure Medication (ASM) reduction and discontinuation, as well as Psychogenic Non-Epileptic Seizure (PNES) spell reduction and resolution in patients with PNES, with and without comorbid epileptic seizures (ES).

METHODS

A retrospective analysis was conducted on data from 145 patients with PNES, including 109 with PNES alone and 36 with PNES plus comorbid epilepsy. Patients were admitted to the Epilepsy Monitoring Unit (EMU) between May 2000 and April 2008, with follow-up clinical data collected until September 2015. Clinical records were thoroughly examined, encompassing the period preceding the PNES diagnosis until either loss to follow-up or September 2015. A subsequent chart review was conducted by two neurologists, covering the period following the diagnosis of PNES until either loss to follow-up or September 2015, which ever came first.

RESULTS

Patients with PNES alone had higher rates of ASM reduction for all variables of ASM reduction measured compared to those with comorbid epilepsy (all at p < 001). Among patients with PNES alone, reductions in ASMs were observed after EMU discharge, but an uptick and plateau were seen in later follow-up years (100% of patients free of ASMs at years 2-3, 20% on at least one ASM by year 7). This pattern differs greatly in PNES + ES patients, in which the only time point at which any patient was able to discontinue all ASMs was at EMU discharge (4.5% of patients), with all patients taking at least one ASM for every other follow-up time point. Reductions in PNES spell frequency did not differ significantly between the two groups (for example PNES spells reduced at final FU 47.2% vs 42.9%, p = 0.65). In both groups, despite an initial drop in variables of PNES spell reduction and resolution in the early years post discharge, there is an eventual rebound and plateau (for example in PNES only patients, 33.9% of patients having no resolution in 1st year FU, which rises to 78% at years 4-5, and plateus around 52.8% at more than 7 years follow-up.) SIGNIFICANCE: This study contributes to the growing body of research focused on improving the current approach to management and prognostic outlook of PNES. Although PNES only patients had higher rates of ASM reduction, the uptick and plateau observed in later years highlights the challenges in managing PNES. Similarly, the continued persistence and rebound of PNES spells underline the continued poor prognostic outcomes associated with this condition.

Functional ataxia in a specialized ataxia center

BACKGROUND

Functional gait is a disorder of ambulation and balance internally inconsistent and incongruent with the phenotypic spectrum of neurological gait disorders.

OBJECTIVES

This paper aims to clinically characterize patients with functional ataxia.

METHODS

Patients with functional ataxia were analyzed out of 1350 patients in Ataxia Unit of the Federal University of São Paulo circa 2008 to 2022.

RESULTS

Thirteen patients (1 %) presented with functional ataxia; all female, with a median age of 34.8 years. Six (46.2 %) had psychiatric comorbidities and 7 (53.8 %) endorsed a trigger. Diagnostic features included variable base and stride (100 %), "huffing and puffing" (30.7 %), knee-buckling (30.7 %), uneconomic posturing (38.5 %), tightrope walking (23 %), and trembling gait (15.4 %). Remarkably, no falls were reported in any case. 53.8 % recovered fully or partially, despite no treatment.

CONCLUSIONS

Variability of base and stride are universal features of functional ataxia, yet falls are inconspicuous. Functional Ataxia is rare even in a specialized ataxia center.

Pain and functional neurological disorder: a systematic review and meta-analysis

BACKGROUND

Functional neurological disorder (FND) is characterised by neurological symptoms, such as seizures and abnormal movements. Despite its significance to patients, the clinical features of chronic pain in people with FND, and of FND in people with chronic pain, have not been comprehensively studied.

METHODS

We systematically reviewed PubMed, Embase and PsycINFO for studies of chronic pain in adults with FND and FND in patients with chronic pain. We described the proportions of patients reporting pain, pain rating and timing, pain-related diagnoses and responsiveness to treatment. We performed random effects meta-analyses of the proportions of patients with FND who reported pain or were diagnosed with pain-related disorders.

RESULTS

Seven hundred and fifteen articles were screened and 64 were included in the analysis. Eight case-control studies of 3476 patients described pain symptoms in a higher proportion of patients with FND than controls with other neurological disorders. A random effects model of 30 cohorts found that an estimated 55% (95% CI 46% to 64%) of 4272 patients with FND reported pain. Random effects models estimated diagnoses of complex regional pain syndrome in 22% (95% CI 6% to 39%) of patients, irritable bowel syndrome in 16% (95% CI 9% to 24%) and fibromyalgia in 10% (95% CI 8% to 13%). Five studies of FND diagnoses among 361 patients with chronic pain were identified. Most interventions for FND did not ameliorate pain, even when other symptoms improved.

CONCLUSIONS

Pain symptoms and pain-related diagnoses are common in FND. Classification systems and treatments should routinely consider pain as a comorbidity in patients with FND.

Neuropsychological evaluation of functional cognitive disorder: A narrative review

Objective: To critically review contemporary theoretical models, diagnostic approaches, clinical features, and assessment findings in Functional Cognitive Disorder (FCD), and make recommendations for neuropsychological evaluation of this condition. Method: Narrative review. Results: FCD is common in neuropsychological practice. It is characterized by cognitive symptoms that are not better explained by another medical or psychiatric disorder. The cognitive symptoms are associated with distress and/or limitations in daily functioning, but are potentially reversible with appropriate identification and treatment. Historically, a variety of diagnostic frameworks have attempted to capture this condition. A contemporary conceptualization of FCD positions it as a subtype of Functional Neurological Disorder, with shared and unique etiological factors. Patients with FCD tend to perform normally on neuropsychological testing or demonstrate relatively weak memory acquisition (e.g. list learning trials) in comparison to strong attention and delayed recall performance. Careful history-taking and behavioral observations are essential to support the diagnosis of FCD. Areas of ongoing controversy include operationalizing "internal inconsistencies" and the role of performance validity testing. Evidence for targeted interventions remains scarce. Conclusions: Neuropsychologists familiar with FCD can uniquely contribute to the care of patients with this condition by improving diagnostic clarity, richening case formulation, communicating effectively with referrers, and leading clinical management. Further research is needed to refine diagnosis, prognosis, and treatment.