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Problem-solving often requires creativity and is critical in everyday life. However, the neurocognitive mechanisms underlying creative problem-solving remain poorly understood. Two mechanisms have been highlighted: the formation of new connections among problem elements and insight solving, characterized by sudden realization of a solution. In this study, we investigated EEG activity during a modified version of the remote associates test, a classical insight problem task that requires finding a word connecting three unrelated words. This allowed us to explore the brain correlates associated with the semantic remoteness of connections (by varying the remoteness of the solution word across trials) and with insight solving (identified as a Eurêka moment reported by the participants). Semantic remoteness was associated with power increase in the alpha band (8-12 Hz) in a left parieto-temporal cluster, the beta band (13-30 Hz) in a right fronto-temporal cluster in the early phase of the task, and the theta band (3-7 Hz) in a bilateral frontal cluster just prior to participants' responses. Insight solving was associated with power increase preceding participants' responses in the alpha and gamma (31-60 Hz) bands in a left temporal cluster and the theta band in a frontal cluster. Source reconstructions revealed the brain regions associated with these clusters. Overall, our findings shed new light on some of the mechanisms involved in creative problem-solving.
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Encéfalo , Solución de Problemas , Humanos , Solución de Problemas/fisiología , Encéfalo/diagnóstico por imagen , Encéfalo/fisiología , Creatividad , Mapeo Encefálico , ElectroencefalografíaRESUMEN
The diagnosis of functional dystonia is challenging because it is difficult to distinguish functional dystonia from other types of dystonia. After diagnostic explanation, multidisciplinary care is recommended, but some patients are resistant to treatments. We used motor blocks in three patients with severe resistant functional dystonia of the upper limbs to test (i) whether joint contracture was present and (ii) whether motor blocks have a therapeutic effect on functional dystonia. Patient 1 showed a good and sustained therapeutic response, Patient 2 experienced a resolution of the dystonic posture that lasted for 10 days, and Patient 3 experienced no effect. Motor blocks may be a useful therapeutic option in chronic treatment-resistant functional dystonia. The treatment effect might be achieved through the experience of normal positioning and functioning of the limb.
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Distonía , Trastornos Distónicos , Trastornos del Movimiento , Humanos , Distonía/tratamiento farmacológico , Trastornos Distónicos/tratamiento farmacológico , Trastornos Distónicos/complicaciones , Trastornos del Movimiento/complicaciones , Extremidad SuperiorRESUMEN
BACKGROUND AND PURPOSE: Prior studies highlighted the high diagnostic specificity (ranging from 92% to 100%) of clinical signs observed in functional neurological disorders (FNDs). However, these signs are rarely looked for by epileptologists when trying to distinguish between functional dissociative seizure (FDS) and epileptic seizure. The aim of this study was to determine the prevalence of inter-ictal clinical signs of FND in a cohort of patients with probable FDS. The secondary objective was to compare the prevalence of inter-ictal FND clinical signs in FDS patients with age- and gender-matched epileptic patients without FDS. METHODS: Patients diagnosed with FDS seen at two tertiary care centres and epileptic outpatients were included in the study. Each patient underwent a physical examination, searching for inter-ictal clinical signs of FND. RESULTS: In the FDS group, 79% of patients presented at least one sign of FND, compared to 16.6% of patients with epilepsy (p < 0.001). Moreover, 66.6% of FDS patients presented three or more FND signs, whereas only 4.1% of epileptic patients did (p < 0.001). The median number of FND clinical signs in the FDS group was four (SD 1.7; 5.5). Using the threshold of three signs or more, the specificity of detecting three or more FND signs was 83.3%, with a sensitivity of 79.2%. CONCLUSION: Inter-ictal clinical signs of FND are present in patients with FDS and should be looked for during neurological examination.
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BACKGROUND: Functional neurological disorder (FND) is a common cause of neurological disability. Despite recent advances in pathophysiological understanding and treatments, application of this knowledge to clinical practice is variable and limited. OBJECTIVE: Our aim was to provide an expert overview of the state of affairs of FND practice across Europe, focusing on education and training, access to specialized care, reimbursement and disability policies, and academic and patient-led representation of people with FND. METHODS: We conducted a survey across Europe, featuring one expert per country. We asked experts to compare training and services for people with FND to those provided to people with multiple sclerosis (MS). RESULTS: Responses from 25 countries revealed that only five included FND as a mandatory part of neurological training, while teaching about MS was uniformly included. FND was part of final neurology examinations in 3/17 countries, unlike MS that was included in all 17. Seventeen countries reported neurologists with an interest in FND but the estimated mean ratio of FND-interested neurologists to MS neurologists was 1:20. FND coding varied, with psychiatric coding for FND impacting treatment access and disability benefits in the majority of countries. Twenty countries reported services refusing to see FND patients. Eight countries reported an FND special interest group or network; 11 reported patient-led organizations. CONCLUSIONS: FND is largely a marginal topic within European neurology training and there is limited access to specialized care and disability benefits for people with FND across Europe. We discuss how this issue can be addressed at an academic, healthcare and patient organization level.
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PURPOSE: Cowden syndrome (CS) is an autosomal dominant disease related to germline PTEN variants and is characterised by multiple hamartomas, increased risk of cancers and frequent brain alteration. Since the behaviour of patients with CS sometimes appears to be inappropriate, we analysed their neuropsychological functioning. METHODS: This monocentric study was conducted between July 2018 and February 2020. A standardised neuropsychological assessment, including an evaluation of social cognition, executive functions, language and dexterity, as well as a cerebral MRI were systematically proposed to all patients with CS. Moreover, PTEN variants were identified. RESULTS: Fifteen patients from 13 families were included, with six non-sense (40%), three missense (20%), five frameshift (33.3%) and one splice site (6.6%) variant types. Twelve patients (80%) had altered social cognition: 10 patients had an abnormal modified Faux-Pas score and 5 had Ekman's facial emotions recognition impairment. Nearly all patients (93%) had impaired dexterity. Cerebral MRI showed various cerebellar anomalies in seven patients (46.7%). CONCLUSION: Altered social cognition and impaired fine dexterity are frequently associated with CS. Further studies are needed to confirm these results and to determine whether dexterity impairment is due to the effect of germline PTEN variants in the cerebellum.
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Síndrome de Hamartoma Múltiple , Humanos , Síndrome de Hamartoma Múltiple/genética , Cognición Social , Fosfohidrolasa PTEN/genética , Mutación de Línea Germinal/genética , Células GerminativasRESUMEN
Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a disabling long-term condition of unknown cause. The National Institute for Health and Care Excellence (NICE) published a guideline in 2021 that highlighted the seriousness of the condition, but also recommended that graded exercise therapy (GET) should not be used and cognitive-behavioural therapy should only be used to manage symptoms and reduce distress, not to aid recovery. This U-turn in recommendations from the previous 2007 guideline is controversial.We suggest that the controversy stems from anomalies in both processing and interpretation of the evidence by the NICE committee. The committee: (1) created a new definition of CFS/ME, which 'downgraded' the certainty of trial evidence; (2) omitted data from standard trial end points used to assess efficacy; (3) discounted trial data when assessing treatment harm in favour of lower quality surveys and qualitative studies; (4) minimised the importance of fatigue as an outcome; (5) did not use accepted practices to synthesise trial evidence adequately using GRADE (Grading of Recommendations, Assessment, Development and Evaluations trial evidence); (6) interpreted GET as mandating fixed increments of change when trials defined it as collaborative, negotiated and symptom dependent; (7) deviated from NICE recommendations of rehabilitation for related conditions, such as chronic primary pain and (8) recommended an energy management approach in the absence of supportive research evidence.We conclude that the dissonance between this and the previous guideline was the result of deviating from usual scientific standards of the NICE process. The consequences of this are that patients may be denied helpful treatments and therefore risk persistent ill health and disability.
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Terapia Cognitivo-Conductual , Síndrome de Fatiga Crónica , Humanos , Síndrome de Fatiga Crónica/diagnóstico , Síndrome de Fatiga Crónica/terapia , Encuestas y Cuestionarios , Terapia por EjercicioRESUMEN
Functional neurological disorder (FND) is a common and disabling disorder, often misunderstood by clinicians. Although viewed sceptically by some, FND is a diagnosis that can be made accurately, based on positive clinical signs, with clinical features that have remained stable for over 100 years. Despite some progress in the last decade, people with FND continue to suffer subtle and overt forms of discrimination by clinicians, researchers and the public. There is abundant evidence that disorders perceived as primarily affecting women are neglected in healthcare and medical research, and the course of FND mirrors this neglect. We outline the reasons why FND is a feminist issue, incorporating historical and contemporary clinical, research and social perspectives. We call for parity for FND in medical education, research and clinical service development so that people affected by FND can receive the care they need.
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Investigación Biomédica , Trastornos de Conversión , Enfermedades del Sistema Nervioso , Humanos , Femenino , Enfermedades del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso/epidemiología , Enfermedades del Sistema Nervioso/terapiaRESUMEN
Functional neurological disorders (FND) are symptoms that can affect a variety of functions including motor, sensory and cognitive. These symptoms are genuinely experienced by the patient and are related to a functional disorder rather than a structural one. There is little epidemiological data on these disorders, but their frequency is well established in clinical practice, it is the second most frequent reason for consultation in Neurology. Despite of the frequency of the disorder, general practitioners and specialists are insufficiently trained in the disease, and patients often suffer from stigmatization and/or unnecessary investigations. It is therefore important to be aware of the diagnostic approach to FND, which mostly relies on positive clinical signs. Psychiatric evaluation can help with the characterization of predisposing, precipitating and perpetuating factors of the symptoms (according to the 3P biopsychosocial model related to FND), and guide their management. Finally, diagnosis explanation is a crucial step in the management of the disease, which can in itself have a therapeutic effect, and allow the patient to adhere to the treatments.
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Trastornos de Conversión , Médicos Generales , Enfermedades del Sistema Nervioso , Humanos , Enfermedades del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso/epidemiología , Trastornos de Conversión/diagnóstico , Trastornos de Conversión/epidemiología , Trastornos de Conversión/psicología , Derivación y ConsultaRESUMEN
After more than twenty years of academic research on functional neurological disorders (FND) throughout the world, a standardized care management strategy has emerged to allow a more adapted care offer to patients with FND, as close as possible to their experience and their needs. With regard to this special issue on FND in collaboration with L'Encéphale and at the initiative of the Neuropsychiatry section of the AFPBN (French Association of Biological Psychiatry and Neuropsychopharmacology), we would like to suggest a summary of all topics discussed in more detail in each article of this special issue, in order to facilitate its reading. We therefore cover the following themes: the initial contact with a patient with FND, the diagnostic process in favor of a positive diagnosis, the physiological, neural and psychological basis of FND, the diagnostic announcement (and its intangibles), the therapeutic patient education in FND, the general principles of therapeutic management through a personalized and multidisciplinary care program, and the validated therapeutic tools available according to the symptoms identified. This article is designed to be of broad interest on FND, supported by tables and figures showing the key points of all these steps, to keep an educational purpose at most. We hope that through this special issue, each health professional will be able to grasp this knowledge and this framework of care as easily and quickly as possible, in order to participate in the standardization of the care offer.
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Trastornos de Conversión , Enfermedades del Sistema Nervioso , Humanos , Trastornos de Conversión/diagnóstico , Trastornos de Conversión/psicología , Trastornos de Conversión/terapia , Escolaridad , Enfermedades del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso/terapiaRESUMEN
Functional neurological disorders have a broad phenotypic spectrum and include different clinical syndromes, which are sometimes associated to each other or appear consecutively over the course of the disease. This clinical anthology provides details on the specific and sensitive positive signs that are to be sought in the context of a suspected functional neurological disorder. Beside these positive elements leading to the diagnosis of functional neurological disorder, we should keep in mind the possibility of an associated organic disorder as the combination of both organic and functional disorders is a relatively frequent situation in clinical practice. Here we describe the clinical characteristics of different functional neurological syndromes: motor deficits, abnormal hyperkinetic and hypokinetic movements, voice or speech disorders, sensory disorders, and functional dissociative seizures. The clinical examination and the identification of positive signs play a critical role in the diagnosis of functional neurological disorder. Knowledge of the specific signs associated with each phenotype render possible to make an early diagnosis. For that matter, it contributes to the improvement of patient care management. It allows to a better engagement in an appropriate care pathway, which influence their prognosis. Highlighting and discussing positive signs with patients can also be an interesting step in the process of explaining the disease and its management.
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Trastornos de Conversión , Humanos , Síndrome , Trastornos de Conversión/complicacionesRESUMEN
INTRODUCTION: The importance to assess and include the frequent comorbidities in the personalised care management plan of patients with functional neurological disorders (FND) has arisen through the years. FND patients are not only complaining from motor and/or sensory symptoms. They also report some non-specific symptoms that participate to the burden of FND. In this narrative review, we aim to better describe these comorbidities in terms of prevalence, clinical characteristics and their variability depending on the subtype of FND. METHODS: The literature was searched for on Medline and PubMed. The search was narrowed to articles between 2000 and 2022. RESULTS: Fatigue is the most common symptom reported in relation to FND (from 47 to 93%), followed by cognitive symptoms (from 80 to 85%). Psychiatric disorders are reported in 40 to 100% FND patients, depending on the FND subtype (functional motor disorder [FMD], functional dissociative seizures [FDS] ) but also on the type of psychiatric disorder (anxiety disorders being the most frequent, followed by mood disorders and neurodevelopmental disorders). Stress factors such as childhood trauma exposure (emotional neglect and physical abuse predominantly) have also been identified in up to 75% of FND patients, along with maladaptive coping strategies. Organic disorders are commonly reported in FND, such as neurological disorders (including epilepsy in FDS [20%] and FMD in Parkinson's Disease [7%]). Somatic symptom disorders including chronic pain syndromes are frequently associated to FND (about 50%). To be noted, recent data also suggest a high comorbidity between FND and hypermobile Ehlers Danlos Syndrome (about 55%). CONCLUSION: Put together, this narrative review highlights the high burden of FND patients, not only due to somatosensory alterations but also by considering the frequent comorbidities reported. Thus, such comorbidities must be taken into consideration when defining the FND personalised care management strategy for the patients.
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Trastornos de Conversión , Enfermedades del Sistema Nervioso , Humanos , Trastornos de Conversión/epidemiología , Trastornos de Conversión/terapia , Trastornos de Conversión/complicaciones , Enfermedades del Sistema Nervioso/complicaciones , Enfermedades del Sistema Nervioso/epidemiología , Enfermedades del Sistema Nervioso/terapia , Comorbilidad , Trastornos Disociativos , Adaptación PsicológicaRESUMEN
Functional neurological disorder (FND) is a common cause of persistent and disabling neurological symptoms. Diagnostic delay may lead to no treatment, inappropriate treatment or even iatrogenic symptoms. Yet, several treatments significantly reduce physical symptoms and improve functioning in FND patients even though not all patients respond to the currently available treatments. This review aims to describe the range of evidence-based rehabilitative and/or psychological therapeutic approaches available for FND patients. The most effective treatments are multidisciplinary and coordinated; using an outpatient or inpatient setting. Building a network of FND-trained healthcare professionals around the patient is an essential aspect of optimal patient management. Indeed, a supportive environment coupled with a collaborative therapeutic relationship improves understanding of FND and appears to help patients engage in appropriate treatments. Patients need to be invested in their own care and have to understand that recovery may depend on their commitment. The conventional treatment combines psychoeducation, physical rehabilitation and psychotherapy (cognitive and behavioral therapy, hypnosis, psychodynamic interpersonal therapy). Early referral of patients to physical therapy is recommended; however, the optimal parameters of treatment, duration and intensity are unknown and seem to vary with the severity and chronicity of symptoms. The goal is to minimize self-awareness by diverting attention or by stimulating automatically generated movements with non-specific and gradual exercises. The use of compensatory technical aids should be avoided as much as possible. Psychotherapeutic management should encourage self-evaluation of cognitive distortions, emotional reactions and maladaptive behaviors while empowering the patient in managing symptoms. Symptom management can use anchoring strategies to fight against dissociation. The aim is to connect to the immediate environment and to enrich one's sensoriality. The psychological interventions should then be adapted to the individual psychopathology, cognitive style and personality functioning of each patient. There is currently no known curative pharmacological treatment for FND. The pharmacological approach rather consists of progressively discontinuing medication that was introduced by default and that could lead to undesirable side effects. Finally, neurostimulation (transcranial magnetic stimulation, transcranial direct current stimulation) can be effective on motor FND.
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Trastornos de Conversión , Estimulación Transcraneal de Corriente Directa , Humanos , Diagnóstico Tardío , Trastornos de Conversión/diagnóstico , Trastornos de Conversión/terapia , Trastornos Disociativos , PsicoterapiaRESUMEN
BACKGROUND: Neurological semiology is often considered by medical students as particularly difficult to learn. Finding alternative teaching methods may improve students' motivation and understanding of this field. METHODS: We developed the "Neurospeed", a game to learn neurological syndromes. We assessed its efficiency on short-term learning of neurological syndromes in third-year medical students, through Multiple Choice Questions (MCQs) before and after the game session. Students' satisfaction was evaluated by a satisfaction survey. RESULTS: Out of the 199 third-year medical students of the Faculty of Medicine Sorbonne Paris Nord, 180 attended the Neurospeed in December 2020, and 148 answered 20 Multiple Choice Questions before and after the game, with significant improvement of their score (p < 0.001). Most of the participants agreed that the game was playful, stimulating, and helpful to learn neurological semiology. CONCLUSIONS: Overall, our results show that the Neurospeed game is an interesting tool as a complement to traditional lectures. Further studies are necessary to compare the efficacy of different types of serious games on short-term and long-term learning of neurological semiology.
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Aprendizaje , Estudiantes de Medicina , Humanos , Motivación , Encuestas y CuestionariosRESUMEN
OBJECTIVES: We aimed to identify existing outcome measures for functional neurological disorder (FND), to inform the development of recommendations and to guide future research on FND outcomes. METHODS: A systematic review was conducted to identify existing FND-specific outcome measures and the most common measurement domains and measures in previous treatment studies. Searches of Embase, MEDLINE and PsycINFO were conducted between January 1965 and June 2019. The findings were discussed during two international meetings of the FND-Core Outcome Measures group. RESULTS: Five FND-specific measures were identified-three clinician-rated and two patient-rated-but their measurement properties have not been rigorously evaluated. No single measure was identified for use across the range of FND symptoms in adults. Across randomised controlled trials (k=40) and observational treatment studies (k=40), outcome measures most often assessed core FND symptom change. Other domains measured commonly were additional physical and psychological symptoms, life impact (ie, quality of life, disability and general functioning) and health economics/cost-utility (eg, healthcare resource use and quality-adjusted life years). CONCLUSIONS: There are few well-validated FND-specific outcome measures. Thus, at present, we recommend that existing outcome measures, known to be reliable, valid and responsive in FND or closely related populations, are used to capture key outcome domains. Increased consistency in outcome measurement will facilitate comparison of treatment effects across FND symptom types and treatment modalities. Future work needs to more rigorously validate outcome measures used in this population.
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Enfermedades del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso/terapia , Evaluación de Resultado en la Atención de Salud , HumanosRESUMEN
OBJECTIVE: Whereas functional symptoms are common in Parkinson's disease (PD), a parkinsonian syndrome may occasionally reflect a pure functional disorder (also named functional parkinsonism [FP]). This review aimed to decipher these entities to clarify the link between functional manifestations and PD. METHODS: Following the PRISMA guidelines, the authors performed a systematic literature search of the PubMed and Science Direct databases for the period 1988 to December 2018 to identify studies of patients with either FP or PD associated with functional neurological symptoms. RESULTS: From the 844 articles screened, 22 were retained, including 12 studies of functional neurological symptoms in PD and 16 studies of FP. The studies of functional symptoms in PD included 121 patients-57% were women, and the mean age was 61.3 years. Psychiatric history (mostly depression) and exposure to triggering stressors were frequent: 60% and 82.5%, respectively. The most common symptom was tremor (33.8%), most often located on the side most affected by PD (50%). Studies of FP included a total of 120 patients-62% were women, and the mean age was 50.7 years. The first FP symptoms appeared on average 5 years before diagnosis, with an abrupt onset in half the cases; 67.6% had a psychiatric history, and 46.8% were exposed to triggering stressors, such as physical injury, stress at work, or loss of family or friends. CONCLUSIONS: Findings suggest a possible relationship between PD and FP. Clinicians should keep in mind the possibility of functional symptoms in PD patients.
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Discinesias/fisiopatología , Trastornos Parkinsonianos/fisiopatología , Trastornos Psicofisiológicos/fisiopatología , Discinesias/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastornos Parkinsonianos/complicaciones , Trastornos Psicofisiológicos/etiologíaRESUMEN
Recent functional imaging findings in humans indicate that creativity relies on spontaneous and controlled processes, possibly supported by the default mode and the fronto-parietal control networks, respectively. Here, we examined the ability to generate and combine remote semantic associations, in relation to creative abilities, in patients with focal frontal lesions. Voxel-based lesion-deficit mapping, disconnection-deficit mapping and network-based lesion-deficit approaches revealed critical prefrontal nodes and connections for distinct mechanisms related to creative cognition. Damage to the right medial prefrontal region, or its potential disrupting effect on the default mode network, affected the ability to generate remote ideas, likely by altering the organization of semantic associations. Damage to the left rostrolateral prefrontal region and its connections, or its potential disrupting effect on the left fronto-parietal control network, spared the ability to generate remote ideas but impaired the ability to appropriately combine remote ideas. Hence, the current findings suggest that damage to specific nodes within the default mode and fronto-parietal control networks led to a critical loss of verbal creative abilities by altering distinct cognitive mechanisms.
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Asociación , Mapeo Encefálico , Encéfalo/diagnóstico por imagen , Creatividad , Vías Nerviosas/patología , Semántica , Adulto , Anciano , Análisis de Varianza , Señales (Psicología) , Femenino , Hemorragia/diagnóstico por imagen , Hemorragia/patología , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Modelos Neurológicos , Vías Nerviosas/diagnóstico por imagen , Pruebas Neuropsicológicas , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/patología , Adulto JovenRESUMEN
SEE BURGESS DOI101093/BRAIN/AWW092 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE : Analogical reasoning is at the core of the generalization and abstraction processes that enable concept formation and creativity. The impact of neurological diseases on analogical reasoning is poorly known, despite its importance in everyday life and in society. Neuroimaging studies of healthy subjects and the few studies that have been performed on patients have highlighted the importance of the prefrontal cortex in analogical reasoning. However, the critical cerebral bases for analogical reasoning deficits remain elusive. In the current study, we examined analogical reasoning abilities in 27 patients with focal damage in the frontal lobes and performed voxel-based lesion-behaviour mapping and tractography analyses to investigate the structures critical for analogical reasoning. The findings revealed that damage to the left rostrolateral prefrontal region (or some of its long-range connections) specifically impaired the ability to reason by analogies. A short version of the analogy task predicted the existence of a left rostrolateral prefrontal lesion with good accuracy. Experimental manipulations of the analogy tasks suggested that this region plays a role in relational matching or integration. The current lesion approach demonstrated that the left rostrolateral prefrontal region is a critical node in the analogy network. Our results also suggested that analogy tasks should be translated to clinical practice to refine the neuropsychological assessment of patients with frontal lobe lesions.
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Mapeo Encefálico , Lóbulo Frontal/patología , Corteza Prefrontal/fisiopatología , Pensamiento/fisiología , Adulto , Anciano , Estudios de Casos y Controles , Imagen de Difusión Tensora , Dominancia Cerebral/fisiología , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Adulto JovenRESUMEN
Reasoning by analogy allows us to link distinct domains of knowledge and to transfer solutions from one domain to another. Analogical reasoning has been studied using various tasks that have generally required the consideration of the relationships between objects and their integration to infer an analogy schema. However, these tasks varied in terms of the level and the nature of the relationships to consider (e.g., semantic, visuospatial). The aim of this study was to identify the cerebral network involved in analogical reasoning and its specialization based on the domains of information and task specificity. We conducted a coordinate-based meta-analysis of 27 experiments that used analogical reasoning tasks. The left rostrolateral prefrontal cortex was one of the regions most consistently activated across the studies. A comparison between semantic and visuospatial analogy tasks showed both domain-oriented regions in the inferior and middle frontal gyri and a domain-general region, the left rostrolateral prefrontal cortex, which was specialized for analogy tasks. A comparison of visuospatial analogy to matrix problem tasks revealed that these two relational reasoning tasks engage, at least in part, distinct right and left cerebral networks, particularly separate areas within the left rostrolateral prefrontal cortex. These findings highlight several cognitive and cerebral differences between relational reasoning tasks that can allow us to make predictions about the respective roles of distinct brain regions or networks. These results also provide new, testable anatomical hypotheses about reasoning disorders that are induced by brain damage. Hum Brain Mapp 37:1953-1969, 2016. © 2016 Wiley Periodicals, Inc.
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Mapeo Encefálico , Encéfalo/fisiología , Formación de Concepto/fisiología , Semántica , Encéfalo/diagnóstico por imagen , Lateralidad Funcional , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Solución de Problemas , Percepción Espacial/fisiologíaRESUMEN
Concept formation is the ability to create an abstract link between dissimilar objects or thoughts and is crucial for abstract and creative thinking. This process is related to the integrity of the prefrontal cortex, given the altered performances reported in patients with frontal damage, particularly those suffering from the behavioural variant of frontotemporal dementia. However, the cognitive mechanisms and neural bases of verbal concept formation are not clearly understood. The present study was aimed at addressing the following unresolved issues regarding concept formation in the field of neurology and cognitive neuroscience: (i) Are alterations in concept formation specific to frontotemporal dementia or are they also present in other cortical neurodegenerative disorders such as Alzheimer's disease? (ii) Is impaired performance in concept formation due to cortical lesions specific to frontotemporal dementia or to a cortico-subcortical frontal syndrome? and (iii) What are the cognitive mechanisms and neural bases underlying concept formation? To address these questions, we designed the Verbal Concept Formation Task, an experimental paradigm based on the similarities test. Patients presenting with severe frontal dysfunction (frontotemporal dementia, n = 18, and the Richardson form of progressive supranuclear palsy, n = 21) or with medial temporal pathology (amnestic mild cognitive impairment or Alzheimer's disease, n = 14) and healthy participants (n = 18) were given the Verbal Concept Formation Task and a large battery of neuropsychological tests. In addition, all participants underwent 3D T1-weighted MRI to analyse grey matter volume using voxel-based morphometry. Frontal patients were significantly impaired on the Verbal Concept Formation Task as compared to non-frontal participants (P = 0.00001). Global performance score was positively correlated with scores in cognitive tasks assessing executive functions and with grey matter volume in several areas, mostly in the frontal-basal-ganglion network. Two types of errors were observed in frontal patients. The most frequent was discriminating instead of grouping items ('linking deficit'). Patients also linked items on a concrete instead of an abstract basis ('abstraction deficit'). Linking and abstraction deficits were related to partially different areas: the linking deficit to the dorsal anterior cingulate cortex, right middle frontal gyrus and both inferior parietal lobules and the abstraction deficit to the head of the caudate nuclei and the left superior frontal gyrus. These data suggest that verbal concept formation requires the integrity of the prefrontal-basal-ganglion functional network. In addition, it can be divided into two distinct cognitive processes, which are underlain by two partially different neural networks.
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Encefalopatías/psicología , Formación de Concepto , Lóbulo Frontal , Demencia Frontotemporal/psicología , Enfermedades Neurodegenerativas/psicología , Adulto , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/psicología , Femenino , Demencia Frontotemporal/patología , Sustancia Gris/patología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Enfermedades Neurodegenerativas/patología , Pruebas Neuropsicológicas , Estudios Prospectivos , Desempeño PsicomotorRESUMEN
BACKGROUND: Management of psychogenic movement disorders (PMDs) is challenging for neurologists and, to date, there is no consensus about their treatment. Recent studies suggested a possible therapeutic effect of repeated transcranial magnetic stimulation (TMS) in psychogenic paralysis and tremor. OBJECTIVE: To document the clinical impact of TMS in PMDs. METHODS: We blindly video scored symptoms of consecutive patients with PMD who were recorded before and after TMS. TMS was delivered at low frequency (0.25 Hz) over the motor cortex contralateral to symptoms. RESULTS: Twenty-four patients were included. They presented with dystonia, myoclonus, tremor, Parkinsonism or stereotypies. The median duration of symptoms before TMS was 2.8 years (6 months to 30 years). The overall score of 75% of patients improved by >50% and, furthermore, the clinical benefits were sustained upon protracted follow-up (median 19.8 months). There was no correlation between improvement and duration of symptoms before TMS. CONCLUSIONS: TMS is a therapeutic option for PMDs, including chronic PMDs.