Recent advances in understanding the neurobiology of pediatric functional neurological disorder.

INTRODUCTION: Functional neurological disorder (FND) is a neuropsychiatric disorder that manifests in a broad array of functional motor, sensory, or cognitive symptoms, which arise from complex interactions between brain, mind, body, and context. Children with FND make up 10%-20% of presentations to neurology services in children's hospitals and up to 20% of adolescents admitted to hospital for the management of intractable seizures. AREAS COVERED: The current review focuses on the neurobiology of pediatric FND. The authors present an overview of the small but growing body of research pertaining to the biological, emotion-processing, cognitive, mental health, physical health, and social system levels. EXPERT OPINION: Emerging research suggests that pediatric FND is underpinned by aberrant changes within and between neuron-glial (brain) networks, with a variety of factors - on multiple system levels - contributing to brain network changes. In pediatric practice, adverse childhood experiences (ACEs) are commonly reported, and activation or dysregulation of stress-system components is a frequent finding. Our growing understanding of the neurobiology of pediatric FND has yielded important flow-on effects for assessing and diagnosing FND, for developing targeted treatment interventions, and for improving the treatment outcomes of children and adolescents with FND.

An Individualized Yoga Intervention for People with Functional Neurological Disorder: Case Series.

Functional neurological disorder (FND) is a heterogeneous condition of neurological symptoms that cannot be linked to a specific neurological cause. Yoga combines movement, breathing, and meditation and has established mind-body effects for people who are managing both psychological and neurological conditions. This case series describes key components of a yoga program for people with FND, evaluating feasibility, acceptability, and efficacy via self-report surveys, clinical assessments, and postintervention interview. Four individuals with FND participated in 45-minute, one-to-one virtual yoga sessions, two times a week for 8 weeks. We measured outcomes in four domains (healthcare utilization, FND symptoms, quality of life and self-efficacy, and function and mobility) at baseline, week 4, and week 8. Assessments included the Psychogenic Movement Disorders Rating Scale, timed up-and-go test, Patient Health Questionnaire-15, Brief Illness Perceptions Questionnaire, 36-Item Short Form Health Survey, and University of Washington Self-Efficacy Scale. Four participants completed at least 8 sessions, and two completed the full intervention (16 sessions). There were no adverse events. Two participants reported positive changes after yoga and improved on all clinical assessments (timed up-and-go test and Psychogenic Movement Disorders Rating Scale). Postintervention interview analysis revealed three themes: negative diagnosis experience, perceived health effects of yoga, and session format preferences. This was an exploratory case series describing a yoga intervention that was associated with some benefits for people with FND (decreased FND symptom severity and increased function, perceived health, quality of life, and self-efficacy). A larger case series is warranted to understand how to best select individuals who would benefit from the program.

Anger regulation in patients with functional neurological disorder: A systematic review.

BACKGROUND: Functional neurological disorder (FND) has been associated with predisposing psychological factors, including dysregulation of anger-related processes. This paper provides a systematic review of the literature on anger regulation in FND. We evaluated anger-related research on patient self-report, observational, and laboratory based measures in FND. The review also addresses adverse childhood experiences and their relation with anger regulation, and the effects of therapies targeting anger regulation in FND. METHODS: MEDLINE, EMBASE, and PsycINFO were searched for both quantitative and qualitative research, published in a peer-reviewed journal with a sample size of at least 5 (registered under Prospero protocol CRD42022314340). RESULTS: A total of 2200 articles were identified. After screening, 54 studies were included in this review (k = 20 questionnaire-based studies, k = 12 laboratory studies, k = 21 using other methods, and k = 1 used both questionnaires and other methods) representing data of 2502 patients with FND. Questionnaire-based studies indicated elevated levels of state anger and trait hostility in patients with FND. Laboratory studies showed a higher tendency to avoid social threat cues, attentional bias towards angry faces, difficulties reliving anger, and preoccupation with frustrating barriers among FND patients versus controls. No specific childhood experiences were identified related to anger regulation in FND, and too few small and uncontrolled studies were available (k = 2) to assess the effects of anger-related interventions in FND. The overall quality of the studies was fair (k = 31) to poor (k = 18). Five studies (k = 5) were rated as having a good quality. CONCLUSIONS: This review suggests that patients with FND have maladaptive anger regulation compared to individuals without FND. The findings also highlight the need for further research on the prevalence and consequences of anger-related processes in the development, diagnosis and treatment of FND.

The Symbolism in a Case of Hysterical Psychosis.

The authors take inspiration from a case of hysterical psychosis to illustrate a typical condition of this evocative disease: the symbolic language of hysteria, conjurer of archetypical images. The authors encourage the clinician not to decode such aspects in rational analytical terms, rather to have a more wide-open approach that promotes the emergence of the individual unconscious, reconnecting with the collective imagination. This approach could help psychiatrists better understand a subject's inner experiences and interpersonal behavior.

Alexithymia and facial emotion recognition in patients with functional neurological disorder.

OBJECTIVES: Patients with functional neurological disorder (FND) are known to have difficulties recognizing and processing emotions. Problems recognizing internal emotional states (alexithymia) are common in FND, but little is known about recognizing emotions expressed by other people. This study investigates whether patients with FND have higher levels of alexithymia and reduced facial emotion recognition compared to healthy controls. METHODS: Patients with FND (n = 31, mean age=42.7 [SD=14.8] years, 54.8% women) were compared to healthy controls (n = 33, mean age=45.1 [SD=16.2] years, 63.6% women). The Bermond-Vorst Alexithymia Questionnaire (BVAQ) was used for the assessment of alexithymia and the Ekman 60 Faces Test (EFT) for facial emotion recognition. RESULTS: Patients with FND had higher levels of alexithymia than healthy controls (BVAQ=71.8 [SD=19.8] versus 59.3 [SD=20.3], p = .02, Cohen's d=0.62). Facial emotion recognition did not significantly differ between FND patients and controls (EFT total score FND: 46.1 [SD=5.9], Controls: 47.5 [SD=5.5], p = .34, Cohen's d=0.24). Only recognition of surprise differed between patients and controls (FND: 8.4 [SD=1.8], Controls: 9.2 [SD=1.0), p = .03, Cohen's d= 0.56). Higher levels of alexithymia were associated with poorer facial emotion recognition, but this relationship was not statistically significant (FND: ß= -0.20, p = .28; Controls: ß=-0.03; p = .87). CONCLUSIONS: The current data confirm prior observations that patients with FND have higher alexithymia levels than controls without FND. Difficulties recognizing emotions among patients with FND primarily involves recognition of internal emotional states rather than recognition of facially expressed emotions by others. These findings require replication in a larger and more divers sample.

Transient resting-state salience-limbic co-activation patterns in functional neurological disorders.

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.

Cortisol in functional neurological disorders: State, trait and prognostic biomarkers.

OBJECTIVE: Biological stress dysregulation, such as a flattened cortisol awakening response (CAR), has been identified in functional neurological disorder (FND). This longitudinal study aimed to explore whether CAR alterations in FND serve as state or trait biomarkers, assessing temporal changes in cortisol and clinical outcomes to test its prognostic value. METHODS: Salivary cortisol was measured in 53 patients with mixed FND at two visits separated by eight months (M0 and M8). CAR was calculated based on five consecutive samples, each taken with 15-min time intervals, collected upon awakening, whereas cortisol amplitude (CAmp) was calculated as the difference between the morning peak and the afternoon trough. Clinical outcome was assessed with the Functional Movement Disorder Rating Scale (S-FMDRS), Clinical global impression (CGI) scores for severity (CGI-S) and improvement (CGI-I) and the short-form health survey (SF-36). RESULTS: No differences in CAR levels were found between M0 and M8 regardless of clinical outcome (remained flattened). However, a good clinical outcome was associated with an earlier peak in the CAR (p = .013, odds ratio: 1.78; 95%-confidence interval: 0.095-1.13). A higher CAmp at M0 predicted a better outcome at M8 (ß = 1.14, 95%-confidence interval:0.15-2.13, p = .03). CONCLUSION: A flattened CAR might represent a trait marker for FND, when an earlier peak in the CAR may serve as a state biomarker. The CAmp demonstrates predictive power for clinical outcome, potentially representing a prognostic biomarker for FND. Further replication and follow-up studies are essential to confirm this suggested role of cortisol as a multifaceted biomarker of FND.

Forearm bisection task suggests an alteration in body schema in patients with functional movement disorders (motor conversion disorders).

OBJECTIVES: To explore potential alterations of the Body Schema, the implicit sensorimotor representation of one's own body, in patients with Functional Movement Disorders (FMD, Motor Conversion Disorders), characterized by neurological symptoms of altered voluntary motor function that cannot be explained by typical medical conditions. This investigation is prompted by the potential dissociation from their reportedly intact sense of ownership. METHODS: 10 FMD patients and 11 healthy controls (HC) underwent the Forearm Bisection Task, aimed at assessing perceived body metrics, which consists in asking the subject, blindfolded, to repeatedly point at the perceived middle point of their dominant forearm with the index finger of their contralateral hand, and a psychometric assessment for anxiety, depression, alexithymia, and tendency to dissociation. RESULTS: FMD patients bisected their forearm more proximally (with an increased shift towards their elbow equal to 7.5%) with respect to HC; average bisection point was positively associated with anxiety levels in the whole sample, and with the tendency to dissociation in the FMD group. CONCLUSIONS: FMD patients perceive their forearm as shorter than HC, suggesting an alteration of their Body Schema. The Body Schema can go through short- and long-term updates in the life course, mainly related to the use of each body segment; we speculate that, despite FMD being a disorder of functional nature, characterized by variability and fluctuations in symptomatology, the lack of sense of agency over a body part might be interpreted by the nervous system as disuse and hence influence the Body Schema, as deficits of organic etiology do.

Attitudes and perceptions of Irish health care professionals regarding functional neurological disorder: A national survey.

BACKGROUND: Functional neurological disorder (FND) is a common and often disabling condition. Limited access to services for FND poses challenges both for patients and their health care providers. This survey explored the attitudes, experiences, support needs and training needs of health care professionals (HCPs) who provide care to individuals with FND in Ireland. METHODS: A broad range of HCPs working with patients with FND in Ireland partook in an anonymous online 12-item survey. Participants were recruited via professional bodies and snowball convenience sampling utilising social media and email invitation. Descriptive and inferential statistics were employed to analyze data. RESULTS: A total of 314 HCPs working in Ireland completed the survey. 80% were female and over half worked in their current role for more than 10 years.   75% of the sample encountered three or less individuals with FND per month. Identified service-related challenges to effective patient care included insufficient clinic time, lack of confidence explaining the diagnosis, and the need for greater access to specialist support.  Data revealed persisting negative attitudes toward FND patients among a proportion of respondents. The majority of respondents did not feel they received adequate education on FND, with the exception of neurologists, of whom 65% felt adequately trained.  The majority of respondents (85%) also felt that people with FND did not have access to appropriate FND services in Ireland. CONCLUSION: This study indicates that there is a significant need to improve FND education among HCPs in Ireland, in addition to developing appropriately resourced, integrated, multidisciplinary care pathways for the FND patient group.

Efficacy of Hypnosis and Catalepsy Induction in Functional Neurological Disorders.

BACKGROUND: Patients with Functional Neurological Disorder (FND) experience complex patterns of motor and/or sensory symptoms. Treatment studies of psychological interventions are promising but limited. OBJECTIVES: The aim of the current pilot study is to investigate the effect of treatment consisting of a combination of hypnosis and catalepsy induction on FND symptom severity. METHODS: A within-subject waiting list-control design was used with 46 patients diagnosed with FND. The treatment consisted of 10 sessions. The primary outcome measure was FND symptom severity (The Psychogenic Movement Disorder Rating Scale; PMDRS). The secondary outcome measures were psychological distress and quality of life. RESULTS: The repeated measures (RM) ANOVA for the PMDRS as outcome measure revealed a significant effect for time with a large effect size (η2 = 0.679). Pairwise comparisons indicated that the effect of time in the treatment period was significant for the measure of FND symptom severity, whereas the waiting list period was not. The effect remained stable even at 8 weeks post treatment. As for the additional measurement, general psychological distress and quality of life, no statistically significant differences between individual time points were found. CONCLUSIONS: This pilot study showed that eight sessions of treatment consisting of a combination of hypnosis and catalepsy induction was effective in reducing FND symptom severity. Some explanations and limitations are provided in the paper as well as several avenues of future research.

Structural and functional changes associated with functional/dissociative seizures: A review of the literature.

INTRODUCTION: The term 'functional/dissociative seizures (FDS)' refers to a paroxysmal, transient clinical manifestation that may include motor, sensory, vegetative, psychological and cognitive signs, similar to the manifestations observed in epileptic seizures. In recent years, there has been an increase of literature in the field of brain imaging research on functional neurological disorders and, more specifically, on FDS. However, most of the studies have been carried out on limited samples. We propose an update of this review work by performing a systematic review of studies performed since 2017 in the field of neuroimaging in patients with FDS. METHODS: We conducted a systematic review of the literature using the PRISMA methodology and reproduced most of the methodological elements of the latest systematic literature review. RESULTS: Our work over the last five years has identified 14 articles. It is still difficult to isolate a distinct structure or network specifically involved in the mechanism of FDS. However, certain structures are recurrently involved in imaging studies, notably the amygdala, the orbitofrontal cortex, and the anterior cingulate cortex. CONCLUSION: The contribution of neuroimaging may allow a more precise explanation of the disorder for patients, avoiding the stigma frequently associated with this diagnosis. as with other 'conversion' phenomena which have traditionally been considered only as 'medically unexplained'. In the longer term and beyond a better understanding of the physiopathology of the disorder, the challenge of this neuroimaging work would be to identify specific imaging biomarkers for a diagnosis of FDS.

Neurometabolic alterations in children and adolescents with functional neurological disorder.

OBJECTIVES: In vivo magnetic resonance spectroscopy (MRS) was used to investigate neurometabolic homeostasis in children with functional neurological disorder (FND) in three regions of interest: supplementary motor area (SMA), anterior default mode network (aDMN), and posterior default mode network (dDMN). Metabolites assessed included N-acetyl aspartate (NAA), a marker of neuron function; myo-inositol (mI), a glial-cell marker; choline (Cho), a membrane marker; glutamate plus glutamine (Glx), a marker of excitatory neurotransmission; γ-aminobutyric acid (GABA), a marker of inhibitor neurotransmission; and creatine (Cr), an energy marker. The relationship between excitatory (glutamate and glutamine) and inhibitory (GABA) neurotransmitter (E/I) balance was also examined. METHODS: MRS data were acquired for 32 children with mixed FND (25 girls, 7 boys, aged 10.00 to 16.08 years) and 41 healthy controls of similar age using both short echo point-resolved spectroscopy (PRESS) and Mescher-Garwood point-resolved spectroscopy (MEGAPRESS) sequences in the three regions of interest. RESULTS: In the SMA, children with FND had lower NAA/Cr, mI/Cr (trend level), and GABA/Cr ratios. In the aDMN, no group differences in metabolite ratios were found. In the pDMN, children with FND had lower NAA/Cr and mI/Cr (trend level) ratios. While no group differences in E/I balance were found (FND vs. controls), E/I balance in the aDMN was lower in children with functional seizures-a subgroup within the FND group. Pearson correlations found that increased arousal (indexed by higher heart rate) was associated with lower mI/Cr in the SMA and pDMN. CONCLUSIONS: Our findings of multiple differences in neurometabolites in children with FND suggest dysfunction on multiple levels of the biological system: the neuron (lower NAA), the glial cell (lower mI), and inhibitory neurotransmission (lower GABA), as well as dysfunction in energy regulation in the subgroup with functional seizures.

A Web-Based Educational Module Using Clinical Neuroscience to Deliver the Diagnosis of Functional Neurological Disorder.

Neuroscience-based patient education has become an evidence-based strategy for enhancing chronic pain treatment. Advances in understanding the neuroscience of functional neurological disorder (FND) may allow similar approaches to be developed and disseminated to clinicians, given the public health need for greater provider awareness and expertise around the condition. Accordingly, the authors developed an online video module for clinicians that delivers neuroscience-based psychoeducation for FND and assessed whether the intervention would be associated with changes in clinicians' perception of FND patients and knowledge about the condition. The online intervention consisted of a 20-minute video module, including an 8-minute scripted role-play that modeled neuroscience-informed diagnosis delivery. Pre- and postintervention questionnaires were embedded into the online module and included a self-assessment of FND-related perceptions and knowledge and a multiple-choice assessment of retention of the neuroscience-based content. Wilcoxon signed-rank tests and McNemar's tests were used for statistical analyses. Of the 103 individuals who submitted surveys, 40 participants provided a complete data set from before and after the intervention. Following the intervention, self-assessment items showed respondents had significantly greater comfort with diagnosis delivery and treatment options and decreased negative perception of FND patients. The percentage of correct responses on a multiple-choice assessment regarding the functional neuroanatomy of FND was significantly increased. In summary, the online neuroscience-based educational intervention was effective for increasing clinician knowledge about FND and comfort with diagnosis delivery and treatment options. Implementing web-based formats may be a viable and cost-effective approach to disseminating knowledge and basic clinical skills in the care of patients with FND.

Habilidades motoras y de procesamiento en personas con enfermedad de Parkinson en comparación con adultos mayores sanos. Un estudio transversal / Motor and process skills of people with parkinson’s disease compared to healthy older adults. A cross-sectional study

Introducción Tanto la enfermedad de Parkinson (EP) como el proceso de envejecimiento están asociados con limitaciones funcionales. El objetivo de este estudio fue determinar las diferencias en habilidades motoras y de procesamiento entre individuos con EP y adultos mayores sanos, así como observar cómo la progresión de la enfermedad afecta al desempeño de las habilidades motoras y de procesamiento en pacientes con EP. Sujetos y métodos Se realizó un estudio transversal. Se empleó la medida de la Assessment of Motor and Process Skills (AMPS) para analizar las diferencias en las habilidades motoras y de procesamiento de tareas cotidianas entre personas con EP y adultos mayores sanos, emparejados en edad y sexo. Se administró la sección III de la Unified Parkinson Disease Rating Scale, la escala de Hoehn y Yahr (HY) y la escala de Schwab & England para determinar la gravedad de la enfermedad. Resultados Se reclutó a 70 participantes (49 pacientes con EP y 21 adultos mayores sanos). Nuestros resultados mostraron que incluso en estadios moderados de la enfermedad, tanto las habilidades motoras como las de procesamiento se encontraron deterioradas en los pacientes con EP en comparación con los adultos mayores sanos (p < 0,001). A medida que avanza la enfermedad, las habilidades motoras y de procesamiento presentan un deterioro significativo en las personas con EP. Conclusiones La EP conduce a un mayor deterioro de las habilidades motoras y de procesamiento en comparación con adultos mayores sanos. A medida que avanzan los estadios de la enfermedad según la escala HY, el rendimiento en las habilidades motoras y de procesamiento se deteriora significativamente entre los estadios moderados y avanzados de la EP. Según la escala AMPS, los pacientes con EP no muestran un deterioro en las habilidades de procesamiento hasta el estadio HY IV, pero muestran deterioro motor en los estadios HY II, III y IV. (AU)

INTRODUCTION Both Parkinson’s disease (PD) and the process of ageing are associated with functional limitations. The aim of this study was to determine the differences in motor and process skills between individuals with PD and healthy older adults, as well as to observe how disease progression affects motor and process skills performance in PD patients. SUBJECTS AND METHODS A cross-sectional study was conducted. The Assessment of Motor and Process Skills (AMPS) measure was employed in order to analyze the differences in the motor and process skills of daily tasks in people with PD and healthy older adults age- and sex-matched. Part III of the Unified Parkinson Disease Rating Scale (UPDRS), the Hoehn and Yahr (HY) scale and the Schwab & England scale was administered to determine the severity of the disease. RESULTS Seventy participants (49 patients with PD and 21 healthy older adults) were recruited for this study. Our results showed that even at moderate stages of the disease, both motor and process skills were found deteriorated in PD patients more than older healthy older adults (p < 0.001). As PD progresses, motor and process skills present significantly deterioration. CONCLUSION. PD leads to a greater deterioration in motor and process skills compared to healthy older adults. As disease stages advance according to the HY scale, performance in motor and process skills deteriorates significantly between moderate and advanced PD stages. According to the AMPS scale, PD patients show no impairment of processing skills up to HY IV, but motor impairment at HY stages II, III and IV.

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

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the possible correlation between SARS-CoV-2 vaccines and the onset of neurological syndromes. The aim was to challenge the association between SARS-CoV-2 vaccinations and the onset of acute functional neurological disorders (FNDs) compared to other neurological syndromes in hospitalized patients. METHODS: In this prospective cohort study, all adult inpatients consecutively admitted to a tertiary neurological centre were included. The prevalence and characteristics of neurological syndromes were compared between unvaccinated and vaccinated cases stratified according to the onset from vaccination. The study involved 843 subjects, namely 411 unvaccinated (UVC) and 432 vaccinated cases; these groups were comparable for demographics and clinical diagnosis distribution. RESULTS: Compared to UVC, subjects hospitalized within the first 30 days from vaccine exhibited higher prevalence of FNDs (12.3% vs. 3.6%; odds ratio 4.2, 95% confidence interval 1.6-11.1) and headache (10.8% vs. 5%; odds ratio 4.1, 95% confidence interval 1.9-8.8) but no other neurological syndromes. The FND cases following vaccinations showed similar premorbid conditions and severity but a higher percentage of sensory symptoms and pain compared to UVC FND cases. CONCLUSIONS: SARS-CoV-2 vaccination is associated with a significant short-term increased risk of FND and headache requiring hospitalization in an acute neurological setting.

A Critical Appraisal of the Whack-a-Mole and Swivel Chair Signs in the Diagnosis of Functional Movement Disorders.

BACKGROUND: The demonstration of positive signs during neurological examination is a cornerstone of the diagnosis of functional movement disorders, however, the available data supporting the diagnostic value of some of these signs is limited. OBJECTIVES: To determine the diagnostic value (sensitivity and specificity) of the "whack-a-mole" (WAM) and "swivel chair" (SC) tests in patients with functional movement disorders (FMD). METHODS: We enrolled patients with functional and organic movements in the WAM test if they exhibited tremor, dystonia, myoclonus, chorea, or tics. For the SC test, patients with a gait disorder as their primary impairment were recruited. Two blinded movement disorder specialists rated the presence of these signs in edited videos. RESULTS: Inclusion criteria were met by 42 patients with FMD and 65 patients with organic movement disorders. Both tests demonstrated high specificity (means, 78% and 96%), but their sensitivity was low (means, 52% and 37%). Interobserver agreement for the WAM sign was 0.77 in the FMD group, against 0.28 in patients with organic movement disorders, whereas Movement Disorders Clinical Practice for Review Only for the SC sign was 0.69 in both groups. CONCLUSIONS: The present study indicates that physicians must be cautious in the application and interpretation of these clinical signs in the diagnosis of functional movement disorders, and they should be carefully considered and used as necessary.

A case of conversion disorder presenting as chronic trismus.

Trismus can be the symptom of several diseases. For the most part, the inability to open the mouth is due to an articular disorder but occasionally, the cause may be extra-articular. In this case, being reported, non-articular hysterical trismus caused the jaw to lock in an 11-year-old boy for 3 months. During this period the jaw was completely locked and the locking was associated with moderate to severe pain. After three sessions of therapy the patient was able to open his mouth 33 mm and his eating was back to normal. Conversion disorders often present with dramatic physical presentation including trismus and jaw lock. This report highlights the importance of complete history taking and a thorough clinical examination to make a correct diagnosis in a patient with trismus.