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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] [MESH Headings] [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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Conejero I, Thouvenot E, Hingray C, Hubsch C, El-Hage W, Carle-Toulemonde G, Rotge JY, Drapier S, Drapier D, Mouchabac S. [Understanding functional neurological disorders: From biological markers to pathophysiological models]. L'ENCEPHALE 2023:S0013-7006(23)00085-4. [PMID: 37394415 DOI: 10.1016/j.encep.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 06/06/2023] [Indexed: 07/04/2023]
Abstract
OBJECTIVES Functional neurological disorders have witnessed intense research activity in the fields of structural and functional neuroimaging for more than twenty years. Thus, we propose a synthesis of recent research findings and etiological hypotheses that have been proposed so far. This work should help clinicians to better understand the nature of the mechanisms involved, but also help patients to increase their knowledge about the biological features underlying their functional symptoms. METHODS We carried out a narrative review of international publications dealing with neuroimaging and biology of functional neurological disorders, from 1997 to 2023. RESULTS Several brain networks underlie functional neurological symptoms. These networks play a role in the management of cognitive resources, in attentional control, emotion regulation, in agency and in the processing of interoceptive signals. The mechanisms of the stress response are also associated with the symptoms. The biopsychosocial model helps to better understand predisposing, precipitating, and perpetuating factors involved. The functional neurological phenotype results from the interaction between: i) a specific pre-existing vulnerability resulting from biological background and epigenetic modifications, and ii) exposure to stress factors, according to the stress-diathesis model. This interaction causes emotional disturbances including hypervigilance, lack of integration of sensations and affects, and emotional dysregulation. These characteristics in turn impact the cognitive, motor and affective control processes related with the functional neurological symptoms. CONCLUSIONS A better knowledge of the biopsychosocial determinants of brain network dysfunctions is necessary. Understanding them would help developing targeted treatments, but is also critical for patients care.
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Affiliation(s)
- Ismael Conejero
- Département de psychiatrie, CHU de Nîmes, PSNREC, Inserm, université de Montpellier, Nîmes, France.
| | - Eric Thouvenot
- Département de Neurologie, CHU Nîmes, université de Montpellier, institut de génomique fonctionnelle, University Montpellier, CNRS, Inserm, Montpellier, France
| | - Coraline Hingray
- Pôle hospitalo-universitaire de psychiatrie d'adultes du Grand Nancy, centre psychothérapique de Nancy, Laxou, France
| | - Cécile Hubsch
- Département de neurologie, unité Parkinson, hôpital Fondation Adolphe-de-Rothschild, Paris, France
| | - Wissam El-Hage
- Clinique psychiatrique universitaire, CHRU de Tours, Tours, France
| | - Guilhem Carle-Toulemonde
- Cabinet de psychosomatique et stimulation magnétique transcrânienne, clinique Saint-Exupéry, 31400 Toulouse, France
| | - Jean-Yves Rotge
- Service de psychiatrie d'adultes, Pitié-Salpêtrière Hospital, AP-HP, Sorbonne université, 47-83, boulevard de l'Hôpital, 75651 Paris, France
| | - Sophie Drapier
- Département de neurologie, CHU de Rennes, CIC Inserm 1414, Rennes, France
| | - Dominique Drapier
- Département de psychiatrie adulte, CH Guillaume-Régnier, université de Rennes, Rennes, France
| | - Stéphane Mouchabac
- Département de psychiatrie, CHU Saint-Antoine, AP-HP, iCRIN Psychiatry (Infrastructure of Clinical Research in Neurosciences-Psychiatry), Institut du cerveau et de la moelle (ICM), Université Sorbonne, Inserm, CNRS, Paris, France
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Weber S, Bühler J, Vanini G, Loukas S, Bruckmaier R, Aybek S. Identification of biopsychological trait markers in functional neurological disorders. Brain 2023; 146:2627-2641. [PMID: 36417451 PMCID: PMC10232283 DOI: 10.1093/brain/awac442] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/07/2022] [Accepted: 11/12/2022] [Indexed: 11/26/2023] Open
Abstract
Stress is a well-known risk factor to develop a functional neurological disorder, a frequent neuropsychiatric medical condition in which patients experience a variety of disabling neurological symptoms. Only little is known about biological stress regulation, and how it interacts with predisposing biological and psychosocial risk factors. Dysregulation of the hypothalamic-pituitary-adrenal axis in patients with functional neurological disorders has been postulated, but its relationship to preceding psychological trauma and brain anatomical changes remains to be elucidated. We set out to study the hypothalamic-pituitary-adrenal axis analysing the cortisol awakening response and diurnal baseline cortisol in 86 patients with mixed functional neurological symptoms compared to 76 healthy controls. We then examined the association between cortisol regulation and the severity and duration of traumatic life events. Finally, we analysed volumetric brain alterations in brain regions particularly sensitive to psychosocial stress, acting on the assumption of the neurotoxic effect of prolonged cortisol exposure. Overall, patients had a significantly flatter cortisol awakening response (P < 0.001) and reported longer (P = 0.01) and more severe (P < 0.001) emotional neglect as compared to healthy controls. Moreover, volumes of the bilateral amygdala and hippocampus were found to be reduced in patients. Using a partial least squares correlation, we found that in patients, emotional neglect plays a role in the multivariate pattern between trauma history and hypothalamic-pituitary-adrenal axis dysfunction, while cortisol did not relate to reduced brain volumes. This suggests that psychological stress acts as a precipitating psychosocial risk factor, whereas a reduced brain volume rather represents a biological predisposing trait marker for the disorder. Contrarily, an inverse relationship between brain volume and cortisol was found in healthy controls, representing a potential neurotoxic effect of cortisol. These findings support the theory of reduced subcortical volumes representing a predisposing trait factor in functional neurological disorders, rather than a state effect of the illness. In summary, this study supports a stress-diathesis model for functional neurological disorders and showed an association between different attributes of trauma history and abnormalities in hypothalamus-pituitary-adrenal axis function. Moreover, we suggest that reduced hippocampal and amygdalar volumes represent a biological 'trait marker' for functional neurological disorder patients, which might contribute to a reduced resilience to stress.
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Affiliation(s)
- 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
- Graduate School for Cellular and Biomedical Sciences (GCB), University of Bern, 3010 Bern, 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
- Graduate School for Health Sciences (GHS), University of Bern, 3012 Bern, Switzerland
| | - Giorgio Vanini
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland
| | - Serafeim Loukas
- Department of Neurology, Psychosomatic Medicine Unit, Inselspital Bern University Hospital, University of Bern, 3012 Bern, Switzerland
- Division of Development and Growth, Department of Pediatrics, University of Geneva, 1211 Geneva, Switzerland
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, 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
- Translational Imaging Center (TIC), Swiss Institute for Translational and Entrepreneurial Medicine, 3010 Bern, Switzerland
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Landa J, Gerner M, Eisenstein E, Barak S. Pediatric Functional Neurological Symptoms Disorder: Walking Ability and Perceived Exertion Post-Pediatric Rehabilitation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:1631. [PMID: 36674392 PMCID: PMC9867415 DOI: 10.3390/ijerph20021631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/29/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
BACKGROUND Adolescents with functional neurological symptoms disorder (FNSD) commonly present walking abnormalities. Walking is influenced by 'objective' (e.g., fitness) and 'subjective' (e.g., fear) components. Rate of perceived exertion (RPE) reflects the interaction between these two components. This study compared the walking ability and RPE before and after rehabilitation of adolescents with FNSD to adolescents with moderate-to-severe traumatic brain injury (TBI). Factors predicting walking and RPE were also examined. METHODS Adolescents with FNSD (n = 31) and adolescents with moderate-to-severe TBI (n = 28) aged 6 to 18 years participated in the study. Participants received a multidisciplinary rehabilitation program. Six-minute walk test (6MWT) and RPE were assessed before and after rehabilitation. RESULTS At pre-test, the TBI group presented lower RPE than the FNSD group (3.38 ± 2.49 and 6.25 ± 2.71, respectively). In the FNSD group, pre-test 6MWT was a significant predictor of post-test 6MWT (adjusted R2 = 0.17; p = 0.01). In the TBI group, post-test 6MWT was significantly predicted by both the pre-test 6MWT and age (adjusted R2 = 0.16; p = 0.04). CONCLUSIONS Prior to the intervention, adolescents with FNSD perceived walking as a more difficult activity than adolescents with TBI. Post-intervention, although the intervention was effective in terms of changes in 6MWT and RPE, the 'subjective' component still contributed to the elevated RPE of the FNSD group.
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Affiliation(s)
- Jana Landa
- Department of Pediatric Rehabilitation, The Edmond and Lily Safra Children’s Hospital, The Chaim Sheba Medical Center, Ramat Gan 5265601, Israel
- The Sackler School of Medicine, Tel Aviv University, Tel Aviv 39040, Israel
| | - Maya Gerner
- Department of Pediatric Rehabilitation, The Edmond and Lily Safra Children’s Hospital, The Chaim Sheba Medical Center, Ramat Gan 5265601, Israel
| | - Etzyona Eisenstein
- Department of Pediatric Rehabilitation, The Edmond and Lily Safra Children’s Hospital, The Chaim Sheba Medical Center, Ramat Gan 5265601, Israel
| | - Sharon Barak
- Department of Pediatric Rehabilitation, The Edmond and Lily Safra Children’s Hospital, The Chaim Sheba Medical Center, Ramat Gan 5265601, Israel
- Department of Nursing, Faculty of Health Science, Ariel University, Ariel 40700, Israel
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Dystonia: Still a Mysterious Syndrome. LIFE (BASEL, SWITZERLAND) 2022; 12:life12070989. [PMID: 35888079 PMCID: PMC9321350 DOI: 10.3390/life12070989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 06/29/2022] [Indexed: 12/02/2022]
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