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Schneider A, Weber S, Wyss A, Loukas S, Aybek S. BOLD signal variability as potential new biomarker of functional neurological disorders. Neuroimage Clin 2024; 43:103625. [PMID: 38833899 PMCID: PMC11179625 DOI: 10.1016/j.nicl.2024.103625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/16/2024] [Accepted: 05/29/2024] [Indexed: 06/06/2024]
Abstract
BACKGROUND Functional neurological disorder (FND) is a common neuropsychiatric condition with established diagnostic criteria and effective treatments but for which the underlying neuropathophysiological mechanisms remain incompletely understood. Recent neuroimaging studies have revealed FND as a multi-network brain disorder, unveiling alterations across limbic, self-agency, attentional/salience, and sensorimotor networks. However, the relationship between identified brain alterations and disease progression or improvement is less explored. METHODS This study included resting-state functional magnetic resonance imaging (fMRI) data from 79 patients with FND and 74 age and sex-matched healthy controls (HC). First, voxel-wise BOLD signal variability was computed for each participant and the group-wise difference was calculated. Second, we investigated the potential of BOLD signal variability to serve as a prognostic biomarker for clinical outcome in 47 patients who attended a follow-up measurement after eight months. RESULTS The results demonstrated higher BOLD signal variability in key networks, including the somatomotor, salience, limbic, and dorsal attention networks, in patients compared to controls. Longitudinal analysis revealed an increase in BOLD signal variability in the supplementary motor area (SMA) in FND patients who had an improved clinical outcome, suggesting SMA variability as a potential state biomarker. Additionally, higher BOLD signal variability in the left insula at baseline predicted a worse clinical outcome. CONCLUSION This study contributes to the understanding of FND pathophysiology, emphasizing the dynamic nature of neural activity and highlighting the potential of BOLD signal variability as a valuable research tool. The insula and SMA emerge as promising regions for further investigation as prognostic and state markers.
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Affiliation(s)
- Ayla Schneider
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, 3010 Bern, Switzerland
| | - Samantha Weber
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, 3010 Bern, Switzerland; University of Zurich, Psychiatric University Hospital Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, 8032 Zurich, Switzerland
| | - Anna Wyss
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Graduate School for Health Sciences (GHS), University of Bern, 3006 Bern, Switzerland
| | - Serafeim Loukas
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Selma Aybek
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Faculty of Science and Medicine, University of Fribourg, 1700 Fribourg, Switzerland.
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2
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Jungilligens J, Perez DL. Predictive Processing and the Pathophysiology of Functional Neurological Disorder. Curr Top Behav Neurosci 2024. [PMID: 38755514 DOI: 10.1007/7854_2024_473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
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.
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Affiliation(s)
- Johannes Jungilligens
- Behavioral Neurology Research Group, Department of Neurology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, Bochum, Germany
| | - David L Perez
- Division of Behavioral Neurology and Integrated Brain Medicine, Department of Neurology, Functional Neurological Disorder Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Division of Neuropsychiatry, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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3
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Weber S, Bühler J, Loukas S, Bolton TAW, Vanini G, Bruckmaier R, Aybek S. Transient resting-state salience-limbic co-activation patterns in functional neurological disorders. Neuroimage Clin 2024; 41:103583. [PMID: 38422831 PMCID: PMC10944183 DOI: 10.1016/j.nicl.2024.103583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 02/09/2024] [Accepted: 02/25/2024] [Indexed: 03/02/2024]
Abstract
BACKGROUND Functional neurological disorders were historically regarded as the manifestation of a dynamic brain lesion which might be linked to trauma or stress, although this association has not yet been directly tested yet. Analysing large-scale brain network dynamics at rest in relation to stress biomarkers assessed by salivary cortisol and amylase could provide new insights into the pathophysiology of functional neurological symptoms. METHODS Case-control resting-state functional magnetic resonance imaging study of 79 patients with mixed functional neurological disorders (i.e., functional movement disorders, functional seizures, persistent perceptual-postural dizziness) and 74 age- and sex-matched healthy controls. Using a two-step hierarchical data-driven neuroimaging approach, static functional connectivity was first computed between 17 resting-state networks. Second, dynamic alterations in these networks were examined using co-activation pattern analysis. Using a partial least squares correlation analysis, the multivariate pattern of correlation between altered temporal characteristics and stress biomarkers as well as clinical scores were evaluated. RESULTS Compared to healthy controls, patients presented with functional aberrancies of the salience-limbic network connectivity. Thus, the insula and amygdala were selected as seed-regions for the subsequent analyses. Insular co-(de)activation patterns related to the salience network, the somatomotor network and the default mode network were detected, which patients entered more frequently than controls. Moreover, an insular co-(de)activation pattern with subcortical regions together with a wide-spread co-(de)activation with diverse cortical networks was detected, which patients entered less frequently than controls. In patients, dynamic alterations conjointly correlated with amylase measures and duration of symptoms. CONCLUSION The relationship between alterations in insular co-activation patterns, stress biomarkers and clinical data proposes inter-related mechanisms involved in stress regulation and functional (network) integration. In summary, altered functional brain network dynamics were identified in patients with functional neurological disorder supporting previously raised concepts of impaired attentional and interoceptive processing.
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Affiliation(s)
- Samantha Weber
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; University of Zurich, Psychiatric University Hospital Zurich, Department of Psychiatry, Psychotherapy and Psychosomatics, 8032 Zurich, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, 3010 Bern, Switzerland; Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
| | - Janine Bühler
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, 3010 Bern, Switzerland
| | - Serafeim Loukas
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland; Division of Development and Growth, Department of Pediatrics, University of Geneva, 1211 Geneva, Switzerland
| | - Thomas A W Bolton
- Department of Clinical Neurosciences, Neurosurgery Service and Gamma Knife Center, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland; Department of Radiology, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland
| | - Giorgio Vanini
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland
| | - Rupert Bruckmaier
- Veterinary Physiology, Vetsuisse Faculty, University of Bern, 3012 Bern, Switzerland
| | - Selma Aybek
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland; Faculty of Science and Medicine, University of Fribourg, 1700 Fribourg, Switzerland
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Assaedi E, Yu XX, Siddiqui J, Shuaib UA. The selfie sign in the diagnosis of functional tremor. Clin Park Relat Disord 2024; 10:100238. [PMID: 38318489 PMCID: PMC10839440 DOI: 10.1016/j.prdoa.2024.100238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 12/03/2023] [Accepted: 01/23/2024] [Indexed: 02/07/2024] Open
Abstract
Functional tremor (FT) is the most common phenotype of functional movement disorders (FMD). Its diagnosis can often be challenging. While positive signs such as tremor variability, distractibility, and entrainment support a diagnosis of FT, these diagnostic clues may not always be present and can be challenging to assess. In this case series, we identify another examination technique which could be of value when assessing FT. In our Movement Disorders clinic, charts were retrospectively reviewed for relevant clinical information. Video examinations were conducted. Obtained videos were either synchronous, via the use of screen recording software during telehealth visits or asynchronous, from self-recorded home videos. In both settings, patients were instructed to self-record their tremor using their phone cameras. Three patients with FT or comorbid FT were identified as demonstrating a unique examination sign. Videos showed an improvement or suppression of the tremor when the phone was held by the affected hand. When compared to a patient with tremor-dominant Parkinson's disease serving as a control, this "selfie sign" was not observed. These observations are preliminary and larger studies are needed to confirm the usefulness of the selfie sign in diagnosing FT. Patient-recorded videos of their tremor can be a convenient and practical way of evaluating suspected FT, especially when paroxysmal or variable symptoms limit the usefulness of classic signs often assessed in the clinic.
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Affiliation(s)
- Ekhlas Assaedi
- Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Xin Xin Yu
- Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Junaid Siddiqui
- Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Umar A Shuaib
- Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
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Edwards M, Koens L, Liepert J, Nonnekes J, Schwingenschuh P, van de Stouwe A, Morgante F. Clinical neurophysiology of functional motor disorders: IFCN Handbook Chapter. Clin Neurophysiol Pract 2024; 9:69-77. [PMID: 38352251 PMCID: PMC10862411 DOI: 10.1016/j.cnp.2023.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/18/2023] [Accepted: 12/27/2023] [Indexed: 02/16/2024] Open
Abstract
Functional Motor Disorders are common and disabling. Clinical diagnosis has moved from one of exclusion of other causes for symptoms to one where positive clinical features on history and examination are used to make a "rule in" diagnosis wherever possible. Clinical neurophysiological assessments have developed increasing importance in assisting with this positive diagnosis, not being used simply to demonstrate normal sensory-motor pathways, but instead to demonstrate specific abnormalities that help to positively diagnose these disorders. Here we provide a practical review of these techniques, their application, interpretation and pitfalls. We also highlight particular areas where such tests are currently lacking in sensitivity and specificity, for example in people with functional dystonia and functional tic-like movements.
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Affiliation(s)
- M.J. Edwards
- Institute of Psychiatry, Psychology and Neuroscience, King’s College London, UK
- Department of Neuropsychiatry, Maudsley Hospital, London, UK
| | - L.H. Koens
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Department of Neurology and Clinical Neurophysiology, Martini Ziekenhuis, Groningen, the Netherlands
| | - J. Liepert
- Kliniken Schmieder Allensbach, Allensbach, Germany
| | - J. Nonnekes
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
- Center of Expertise for Parkinson & Movement Disorders, Department of Rehabilitation, Nijmegen, the Netherlands
- Department of Rehabilitation, Sint Maartenskliniek, Ubbergen, the Netherlands
| | | | - A.M.M. van de Stouwe
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, Groningen, the Netherlands
- Department of Neurology, Ommelander Ziekenhuis, Scheemda, the Netherlands
| | - F. Morgante
- Neurosciences Research Centre, Molecular and Clinical Sciences Research Institute, St George's University of London, London, UK
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6
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Huys ACML, Haggard P. "Perceived Intention"-Motor intention perceived as movement despite paralysis and retained insight. J Neurol 2023; 270:6141-6145. [PMID: 37515732 DOI: 10.1007/s00415-023-11884-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 07/16/2023] [Accepted: 07/17/2023] [Indexed: 07/31/2023]
Affiliation(s)
- Anne-Catherine M L Huys
- Department of Neurology, Cambridge University Hospitals NHS Foundation Trust, Neurosciences, Hills Road, Cambridge, CB2 0QQ, UK.
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, London, UK
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Palmer DD, Gamble M, Higgins M, Maley J, Watson E. Outcomes of an Integrated Multidisciplinary Clinic for People with Functional Neurological Disorder. Mov Disord Clin Pract 2023; 10:967-973. [PMID: 37332646 PMCID: PMC10272915 DOI: 10.1002/mdc3.13757] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/31/2023] [Accepted: 04/15/2023] [Indexed: 06/20/2023] Open
Abstract
Background Functional neurological disorder (FND) is a disabling condition which has poor prognosis without treatment. This study aimed to evaluate the effectiveness of an outpatient integrated multidisciplinary intervention for the condition. Objectives This study aimed to assess the outcomes of a pilot integrated multidisciplinary treatment clinic for FND with motor symptoms. Methods Patients were seen simultaneously by a neurology doctor, a physiotherapist, a clinical psychologist, and sometimes a psychiatrist. The primary endpoint was change in quality of life measured by Short Form-36 (SF-36). Secondary outcomes were change in work and social participation measured by the Work and Social Adjustment Scale (WSAS), ability to participate in full-time or part-time employment, self-rated understanding of FND, and self-rated agreement with the diagnosis of FND. Over the year, 13 patients were recruited to the clinic, and 11 agreed to participate in the outcome study. Results Statistically significant improvements in quality of life were seen across seven out of eight domains of the SF-36, with improvements in individual domains of between 23 and 39 points (of a possible 100). Mean Work and Social Adjustment Scale score halved from 26 to 13 (worst possible is 40). Of the 12 patients treated, one began to work again after complete unemployment, and two who had been working reduced hours due to disability resumed full time work. No patients had worsened occupational status. Conclusions This intervention is associated with substantial improvements in quality of life and function, and may be more amenable to delivery at non-specialist centers than other described interventions for FND.
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Affiliation(s)
- David D.G. Palmer
- Department of NeurologyCapital and Coast District Health BoardWellingtonNew Zealand
| | - Mary Gamble
- ORA Wellington Inpatient Physiotherapy TeamCapital and Coast District Health BoardWellingtonNew Zealand
| | - Matthew Higgins
- Consultation Liaison Psychiatry Service, Mental Health, Addictions and Intellectual Disability ServicesCapital and Coast District Health BoardWellingtonNew Zealand
| | - Jenny Maley
- Consultation Liaison Psychiatry Service, Mental Health, Addictions and Intellectual Disability ServicesCapital and Coast District Health BoardWellingtonNew Zealand
| | - Eloise Watson
- Department of NeurologyCapital and Coast District Health BoardWellingtonNew Zealand
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8
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Gilmour GS, Lidstone SC. Moving Beyond Movement: Diagnosing Functional Movement Disorder. Semin Neurol 2023; 43:106-122. [PMID: 36893796 DOI: 10.1055/s-0043-1763505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Functional movement disorder (FMD) is a complex neuropsychiatric syndrome, encompassing abnormal movements and weakness, and is a common cause of potentially disabling neurological symptoms. It is vital to recognize that FMD is a syndrome, with nonmotor manifestations negatively affecting a patient's quality of life. This review highlights a diagnostic algorithm, where a history suggestive of FMD is combined with the presence of positive signs on examination and appropriate investigations to make the diagnosis. Positive signs indicate internal inconsistency such as variability and distractibility, and clinical findings that are incongruent with other known neurological disease. Importantly, the clinical assessment acts as the first opportunity to allow patients to understand FMD as the cause for their symptoms. Accurate and early diagnosis of FMD is necessary given that it is a treatable and potentially reversible cause of disability, with significant risk of iatrogenic harm associated with misdiagnosis.
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Affiliation(s)
- Gabriela S Gilmour
- Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic, University Health Network, Toronto, Ontario, Canada
| | - Sarah C Lidstone
- Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic, University Health Network, Toronto, Ontario, Canada.,Integrated Movement Disorders Program, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada.,KITE Research Institute, Toronto Rehabilitation Institute, University Health Network, Toronto, Canada
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9
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Verrel J, Chwolka F, Filevich E, Moyé J, Paulus T, Zittel S, Bäumer T, Münchau A, Weissbach A. Impaired Metacognition of Voluntary Movement in Functional Movement Disorder. Mov Disord 2023; 38:435-443. [PMID: 36606550 DOI: 10.1002/mds.29303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/22/2022] [Accepted: 12/13/2022] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Motor symptoms in functional movement disorders (FMDs) are experienced as involuntary but share characteristics of voluntary action. Clinical and experimental evidence indicate alterations in monitoring, control, and subjective experience of self-performed movements. OBJECTIVE The objective of this study was to test the prediction that FMDs are associated with a reduced ability to make accurate (metacognitive) judgments about self-performed movements. METHODS We compared 24 patients with FMD (including functional gait disturbance, functional tremor, and functional tics) with 24 age- and sex-matched healthy control subjects in a novel visuomotor-metacognitive paradigm. Participants performed target-directed movements on a graphics tablet with restricted visual feedback, decided which of two visually presented trajectories was closer to their preceding movement, and reported their confidence in the visuomotor decision. We quantified individual metacognitive performance as participants' ability to assign high confidence preferentially to correct visuomotor decisions. RESULTS Patients and control subjects showed comparable motor performance, response accuracy, and use of the confidence scale. However, visuomotor sensitivity in the trajectory judgment was reduced in patients with FMD compared with healthy control subjects. Moreover, metacognitive performance was impaired in patients, that is, their confidence ratings were less predictive of the correctness of visuomotor decisions. Exploratory subgroup analyses suggest metacognitive deficits to be most pronounced in patients with a functional gait disturbance or functional tremor. CONCLUSIONS Patients with FMD exhibited deficits both when making visuomotor decisions about their own movements and in the metacognitive evaluation of these decisions. Reduced metacognitive insight into voluntary motor control may play a role in FMD pathophysiology and could lay the groundwork for new treatment strategies. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Julius Verrel
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Fabian Chwolka
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Elisa Filevich
- Bernstein Center for Computational Neuroscience, Berlin, Germany
- Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin, Germany
- Institute of Psychology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Josephine Moyé
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Theresa Paulus
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Simone Zittel
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tobias Bäumer
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Alexander Münchau
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Anne Weissbach
- Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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10
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Autism Spectrum Disorder May Be Highly Prevalent in People with Functional Neurological Disorders. J Clin Med 2022; 12:jcm12010299. [PMID: 36615098 PMCID: PMC9821674 DOI: 10.3390/jcm12010299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/13/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Recent observations suggest that autism spectrum disorder (ASD) co-occurs in people with a functional neurological disorder (FND), but little systematic data are available on the relationship between FND and autism. The study aimed to assess the self-reported autistic traits via a standardized questionnaire and the prevalence of previously diagnosed ASD among people with FND and their 1st-degree relatives. We performed a survey of members of the patient organization FNDHope, using a self-completed questionnaire for screening for autistic traits and ASD: the adult autism subthreshold spectrum (AdAS spectrum). There were 344 respondents diagnosed with FND with a mean age of 39.8 ± 11.6 years (female sex 90%). Eight per cent of respondents volunteered a previous diagnosis of ASD, and 24% reported a 1st-degree relative with a formal diagnosis of ASD, mostly their children. We found that 69% of respondents had scores in the AdAS spectrum indicating a clinically significant ASD and 21% indicating autistic traits. Further studies are needed to provide more evidence regarding the prevalence of ASD in people with FND and how this may influence the aetiology, treatment selection and prognosis.
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11
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Fiorio M, Braga M, Marotta A, Villa-Sánchez B, Edwards MJ, Tinazzi M, Barbiani D. Functional neurological disorder and placebo and nocebo effects: shared mechanisms. Nat Rev Neurol 2022; 18:624-635. [PMID: 36075980 DOI: 10.1038/s41582-022-00711-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2022] [Indexed: 11/09/2022]
Abstract
Functional neurological disorder (FND) is characterized by neurological symptoms that cannot be explained by a structural neurological cause. Among the different aetiological models that have been proposed for FND, of note is the Bayesian predictive coding model, which posits that perception relies on top-down cortical predictions (priors) to infer the source of incoming sensory information. This model can also apply to non-pathological experiences, such as placebo and nocebo effects, wherein sensory information is shaped by prior expectations and learning. To date, most studies of the relationship between placebo and nocebo effects and FND have focused on the use of placebos for diagnosis and treatment of FND. Here, we propose that this relationship might go beyond diagnosis and therapy. We develop a framework in which shared cognitive, personality and neuroanatomical factors justify the consideration of a deeper link between FND and placebo and nocebo effects. This new perspective might offer guidance for clarification of the pathogenesis of FND and for the identification of potential biomarkers and therapeutic targets.
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Affiliation(s)
- Mirta Fiorio
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Miriam Braga
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Angela Marotta
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | | | - Mark J Edwards
- Institute of Molecular and Clinical Sciences, St George's University of London, London, UK
| | - Michele Tinazzi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Diletta Barbiani
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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12
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Huys ACML, Haggard P, Bhatia KP, Edwards MJ. No exaggerated tremor severity perception in functional tremor. J Neurol 2022; 269:6043-6048. [PMID: 35857138 DOI: 10.1007/s00415-022-11265-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 06/25/2022] [Accepted: 06/29/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Symptoms of functional neurological disorder tend to be variable, yet patients often report them being present constantly and of permanently severe intensity. Furthermore, they typically worsen when they are mentioned or during clinical examination. Such phenomena are sometimes interpreted as indicating symptom exaggeration or even fabrication. METHODS To test the notion of inaccurate symptom perception or reporting, we directly compared subjective to objective tremulousness of reaching movements in people with a functional action tremor, people with an organic action tremor and healthy controls. Identical subjective and objective measures were used, thus eliminating any potential metacognitive confounders. Furthermore, we assessed both immediate perceptual experience with a real-time perceptual task, offering the most direct comparison; and near-time retrospective reports as the latter contribute to peoples' overall judgement of their condition. RESULTS There was no significant difference in subjective compared to objective tremor severity between the three groups for either the real-time or retrospective conditions. CONCLUSION People with functional tremor do not perceive or report their tremor in an exaggerated manner, compared to people with an organic tremor or healthy controls. We propose that symptom exacerbation through attentional mechanisms provides an alternative explanation for findings that are frequently attributed to 'exaggeration'.
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Affiliation(s)
- Anne-Catherine M L Huys
- Department of Clinical and Movement Neurosciences, University College London Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
| | - Patrick Haggard
- Institute of Cognitive Neuroscience, University College London, London, UK
| | - Kailash P Bhatia
- Department of Clinical and Movement Neurosciences, University College London Queen Square Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK
| | - Mark J Edwards
- Neuroscience Research Centre, Institute of Molecular and Cell Sciences, St George's University of London, London, UK
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13
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Jungilligens J, Paredes-Echeverri S, Popkirov S, Barrett LF, Perez DL. A new science of emotion: implications for functional neurological disorder. Brain 2022; 145:2648-2663. [PMID: 35653495 PMCID: PMC9905015 DOI: 10.1093/brain/awac204] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/28/2022] [Accepted: 05/20/2022] [Indexed: 01/11/2023] Open
Abstract
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.
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Affiliation(s)
- Johannes Jungilligens
- Correspondence to: Johannes Jungilligens University Hospital Knappschaftskrankenhaus Bochum Department of Neurology In der Schornau 23-25 44892 Bochum, Germany E-mail:
| | | | - Stoyan Popkirov
- Department of Neurology, University Hospital Knappschaftskrankenhaus Bochum, Ruhr University Bochum, Bochum, Germany
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Stager L, Morriss S, McKibben L, Grant M, Szaflarski JP, Fobian AD. Sense of control, selective attention and cognitive inhibition in pediatric functional seizures: A prospective case-control study. Seizure 2022; 98:79-86. [PMID: 35430472 PMCID: PMC9081274 DOI: 10.1016/j.seizure.2022.03.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/21/2022] Open
Abstract
PURPOSE To date, laboratory-based experimental behavioral methods have not been used to identify factors associated with pediatric functional seizures (FS), leaving a critical gap for effective treatment development. METHODS Children ages 13-18 with video-EEG-confirmed FS were matched to controls (MCs) based on income, sex, race, and age. A modified Stroop task which included a condition requiring participants to report the ink colors in which seizure symptom words were written (e.g., "shaking" in blue) measured selective attention and cognitive inhibition through response time. The magic and turbulence task assessed sense of control in three conditions (magic, lag, turbulence). Children with FS were asked to report premonitory symptoms predicting FS. RESULTS Participants included 26 children with FS and 26 MCs (Meanage=15.2, 74% female, 59% white). On Stroop, children with FS had a slower reaction time (Mean=1193.83) than MCs (Mean=949.26, p = 0.022) for seizure symptom words. Children with FS had significantly poorer sense of control in the turbulence condition of the magic and turbulence task (Mean=-3.99, SD=8.83) than MCs (Mean=-11.51, SD=7.87; t(20)=-2.61, p =0.017). Children with FS (Mean=-1.80, SD=6.54) also had significantly poorer sense of control in the magic condition than MCs (Mean=-5.57, SD=6.01; p =0.028). Ninety-eight percent of patients endorsed premonitory symptoms. CONCLUSION Compared with MCs, children with FS have (1) poorer selective attention and cognitive inhibition when presented with seizure-related information and (2) lower sense of control (i.e. poorer awareness that their control was manipulated). Premonitory symptoms were common. Sense of control, selective attention, and inhibition may be novel treatment targets for FS intervention.
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Affiliation(s)
- Lindsay Stager
- Department of Psychology, University of Alabama at Birmingham, United States
| | - Skylar Morriss
- Department of Psychology, University of Alabama at Birmingham, United States
| | - Lauren McKibben
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, United States; Department of Anesthesiology, University of North Carolina, Chapel Hill, United States
| | - Merida Grant
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, United States
| | - Jerzy P Szaflarski
- Departments of Neurology, Neurosurgery and Neurobiology and the UAB Epilepsy Center, University of Alabama at Birmingham, United States
| | - Aaron D Fobian
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, United States.
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Functional neurological disorder: new subtypes and shared mechanisms. Lancet Neurol 2022; 21:537-550. [PMID: 35430029 PMCID: PMC9107510 DOI: 10.1016/s1474-4422(21)00422-1] [Citation(s) in RCA: 118] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/14/2021] [Accepted: 11/24/2021] [Indexed: 01/12/2023]
Abstract
Functional neurological disorder is common in neurological practice. A new approach to the positive diagnosis of this disorder focuses on recognisable patterns of genuinely experienced symptoms and signs that show variability within the same task and between different tasks over time. Psychological stressors are common risk factors for functional neurological disorder, but are often absent. Four entities-functional seizures, functional movement disorders, persistent perceptual postural dizziness, and functional cognitive disorder-show similarities in aetiology and pathophysiology and are variants of a disorder at the interface between neurology and psychiatry. All four entities have distinctive features and can be diagnosed with the support of clinical neurophysiological studies and other biomarkers. The pathophysiology of functional neurological disorder includes overactivity of the limbic system, the development of an internal symptom model as part of a predictive coding framework, and dysfunction of brain networks that gives movement the sense of voluntariness. Evidence supports tailored multidisciplinary treatment that can involve physical and psychological therapy approaches.
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Huys AML, Haggard P, Bhatia KP, Edwards MJ. A Note of Caution on Distorted Visual Feedback as a Treatment for Functional Movement Disorders. Mov Disord Clin Pract 2021; 9:275-277. [DOI: 10.1002/mdc3.13386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/04/2021] [Accepted: 11/08/2021] [Indexed: 11/07/2022] Open
Affiliation(s)
- Anne‐Catherine M. L. Huys
- Department of Clinical and Movement Neurosciences University College London Queen Square Institute of Neurology London United Kingdom
| | - Patrick Haggard
- Institute of Cognitive Neuroscience University College London London United Kingdom
| | - Kailash P. Bhatia
- Department of Clinical and Movement Neurosciences University College London Queen Square Institute of Neurology London United Kingdom
| | - Mark J. Edwards
- Neuroscience Research Centre, Institute of Molecular and Cell Sciences St George's University of London London United Kingdom
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