Neurologic diagnostic criteria for functional neurologic disorders

Functional Movement Disorder: Assessment and Treatment

Functional movement disorder (FMD) is a common, potentially reversible source of disability in neurology. Over the last two decades, there have been major advances in our understanding of the clinical picture, diagnosis, and management of this condition. Motor presentation is heterogeneous and several non-motor symptoms (e.g., pain, fatigue) are part of the clinical spectrum. The diagnosis should be made by neurologists or neuropsychiatrists based on the presence of positive signs of inconsistency and incongruence with neurological diseases. Promising evidence has accumulated for the efficacy of physiotherapy, psychotherapy, or both in the management of FMD, for a majority of patients.

Perception-Action Integration Is Altered in Functional Movement Disorders

BACKGROUND

Although functional neurological movement disorders (FMD) are characterized by motor symptoms, sensory processing has also been shown to be disturbed. However, how the integration of perception and motor processes, essential for the control of goal-directed behavior, is altered in patients with FMD is less clear. A detailed investigation of these processes is crucial to foster a better understanding of the pathophysiology of FMD and can systematically be achieved in the framework of the theory of event coding (TEC).

OBJECTIVE

The aim was to investigate perception-action integration processes on a behavioral and neurophysiological level in patients with FMD.

METHODS

A total of 21 patients and 21 controls were investigated with a TEC-related task, including concomitant electroencephalogram (EEG) recording. We focused on EEG correlates established to reflect perception-action integration processes. Temporal decomposition allowed to distinguish between EEG codes reflecting sensory (S-cluster), motor (R-cluster), and integrated sensory-motor processing (C-cluster). We also applied source localization analyses.

RESULTS

Behaviorally, patients revealed stronger binding between perception and action, as evidenced by difficulties in reconfiguring previously established stimulus-response associations. Such hyperbinding was paralleled by a modulation of neuronal activity clusters, including reduced C-cluster modulations of the inferior parietal cortex and altered R-cluster modulations in the inferior frontal gyrus. Correlations of these modulations with symptom severity were also evident.

CONCLUSIONS

Our study shows that FMD is characterized by altered integration of sensory information with motor processes. Relations between clinical severity and both behavioral performance and neurophysiological abnormalities indicate that perception-action integration processes are central and a promising concept for the understanding of FMD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Impaired Metacognition of Voluntary Movement in Functional Movement Disorder

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.

The clinical management of functional neurological disorder: A scoping review of the literature

OBJECTIVE

To date, there have been no reviews bringing together evidence on the clinical management of functional neurological disorder (FND) and patients', caregivers', and healthcare workers' experiences. This review provides an overview of the literature focused on the clinical management of FND.

METHODS

Four databases were searched, and a consultation exercise was conducted to retrieve relevant records dated from September 2010 to September 2020. Articles documenting diagnostic methods, treatments or interventions, or the experiences and perspectives of patients and healthcare workers in the clinical management of FND were included.

RESULTS

In total, 2756 records were retrieved, with 162 included in this review. The diagnostic methods reported predominantly included positive clinical signs, v-EEG and EEG. Psychological treatments and medication were the most reported treatments. Mixed findings of the effectiveness of CBT were found. Haloperidol, physiotherapy and scripted diagnosis were found to be effective in reducing FND symptoms. Several facilitators and barriers for patients accessing treatment for FND were reported.

CONCLUSION

The literature describing the clinical management for FND has increased considerably in recent times. A wide variety of diagnostic tools and treatments and interventions were found, with more focus being placed on tests that confirm a diagnosis than 'rule-out' tests. The main treatment type found in this review was medication. This review revealed that there is a lack of high-quality evidence and reflects the need for official clinical guidelines for FND, providing healthcare workers and patients the support needed to navigate the process to diagnose and manage FND.

Functional Neurological Disorders: Clinical Spectrum, Diagnosis, and Treatment

BACKGROUND

Functional neurological disorders (FNDs) are common but often misdiagnosed.

REVIEW SUMMARY

The incidence of FNDs is between 4 and 12 per 100,000, comparable to multiple sclerosis and amyotrophic lateral sclerosis, and it is the second most common diagnosis in neurology clinics. Some clues in the history are sudden onset, intermittent time course, variability of manifestation over time, childhood trauma, and history of other somatic symptoms. Anxiety and depression are common, but not necessarily more than in the general population. Although there are no tests currently capable of demonstrating whether symptoms are willfully produced, there may not be a clear categorical difference between voluntary and involuntary symptoms. The prognosis of an FND is linked to early diagnosis and symptom duration, but unfortunately, the majority of the patients are diagnosed after considerable delays.

CONCLUSIONS

A positive diagnosis of FNDs can be made on the basis of history and neurological signs without reliance on psychological stressors. Past sensitizing events and neurobiological abnormalities contribute to the pathogenesis of FNDs. Physical rehabilitation and psychological interventions alone or in combination are helpful in the treatment.

Inactivated COVID-19 vaccine induced acute stroke-like focal neurologic symptoms: a case series

Background

A subgroup of individuals experienced stroke-like symptoms after receiving an inactivated COVID-19 vaccine. We present clinical characteristics, neuroimaging, and outcome of these patients.

Methods

Medical personals who had neurological symptoms after receiving inactivated COVID-19 vaccine were enrolled. Clinical, laboratory investigation and neuroimaging were collected. Subjects were prospectively followed-up on clinical and neuroimaging to detect brain parenchymal or cerebrovascular abnormality.

Results

Nineteen out of 385 subjects (4.9%) developed neurological symptoms after vaccination. There was a female predominance (89.5%) with mean age of 34 ± 7.5 years. Majority of patients (52.6%) had symptoms within 60 min after vaccination. The most common neurological symptoms were numbness (94.7%) followed by headache (52.6%) and weakness (47.4%). The most common neurological signs were sensory deficit (79%) followed by motor weakness (52.6%) and tongue deviation (26.3%). Recurrent headache was observed in most patients (89.5%) during followed up. Serial brain imaging was done in all patients with median follow-up interval of 18 days. There was no evidence of acute brain infarction in any of the patients, 84.2% had no vascular abnormality, 15.8% had transient focal narrowing of cerebral vessels. Outcome was favorable, modified ranking scale 0–1 for all patients at 4 weeks after vaccination.

Conclusions

Transient focal neurological symptoms and deficits can be found after COVID-19 vaccination. However, benefit to stop COVID-19 pandemic by vaccination is outweighed by these seemingly reversible side effects. The pathophysiology underlined these phenomena should be further investigated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02739-6.

Consistency of inclusion criteria for functional movement disorder clinical research studies: A systematic review

BACKGROUND: Functional movement disorders (FMDs) are a common cause of disability. With an increasing research interest in FMD, including the emergence of intervention trials, it is crucial that research methodology be examined, and standardized protocols be developed. OBJECTIVE: To characterize the current inclusion criteria used to select patients for FMD research studies and review the consistency and appropriateness of these criteria. METHODS: We identified studies of potential biomarkers for FMD that were published over the last two decades and performed a qualitative analysis on the finally included studies. RESULTS: We identified 79 articles and found inconsistent inclusion criteria. The Fahn-Williams and DSM-IV criteria were the most commonly applied, but neither accounted for the majority (Fahn-Williams 46%, DSM-IV 32% of the total). The selection of the inclusion criteria depended in part on the phenotype of FMD under investigation. We also identified inclusion methodologies that were not appropriate, such as the inclusion of low-certainty diagnoses and diagnosing by excluding specific biomarkers rather than including patients based on clinical characteristics that commonly are thought to suggest FMD. CONCLUSIONS: Significant variability exists with the inclusion criteria for FMD research studies. This variability could limit reproducibility and the appropriate aggregation of data for meta-analysis. Advancing FMD rehabilitation research will need standardized inclusion criteria. We make some suggestions.

Evaluation of Individualized Multi-Disciplinary Inpatient Treatment for Functional Movement Disorders

BACKGROUND

Functional movement disorders (FMD) are associated with considerable morbidity and impairment of quality of life. Specialized treatment is scarce and data on efficacy of different therapies are limited.

OBJECTIVE

To evaluate a multi-modal inpatient treatment program for patients with FMD.

METHODS

Thirty-one patients with FMD were analyzed before (t1) and after multi-modal inpatient treatment (t2) by a blinded video rating using the Psychogenic Movement Disorder Rating Scale (PMDRS), the simplified Functional Movement Disorder Rating Scale (S-FMDRS), and the Clinical Global Impression Scale of Severity (CGI-S), as well as patients' self-rating. In 23 out of 31 patients a 5 months follow-up investigation was performed (t3). Wilcoxon signed-rank test and Friedman test were used for rating scale and self-rating comparisons over time. Spearman correlation was used for correlation of symptom improvement and clinical characteristics.

RESULTS

Video rating revealed significant reduction of scores after therapy (median PMDRS t1 = 24, t2 = 8, P = 0.0006; S-FMDRS t1 = 11, t2 = 4, P = 0.008; CGI-S t1 = 4, t2 = 3, P = 0.000136) with sustained score decrease in follow-up evaluations (PMDRS t1 = 31, t2 = 8, t3 = 7, P = 0.000032; S-FMDRS t1 = 12, t2 = 4, t3 = 3, P = 0.000888; CGI-S t1 = 4, t2 = 3, t3 = 3, P = 0.000032). Patients reported a stable reduction of symptoms in the self-rating (CGI-S t1 = 5, t2 = 4, t3 = 4, P = 0.016). Age correlated with treatment response with older patients showing better improvement, but disease duration did not correlate with outcome. Patients who suffered from physical trauma, sexual or physical abuse had smaller score reductions.

CONCLUSION

Blinded video and self-rating assessment showed significant score reduction in patients with FMD after an individualized interdisciplinary inpatient intervention.

Attentional Processing and Interpretative Bias in Functional Neurological Disorder

OBJECTIVE

Altered attentional processing (automatically attending to negative or illness-relevant information) and interpretative biases (interpreting ambiguous information as negative or illness relevant) may be mechanistically involved in functional neurological disorder (FND). Common mechanisms between FND and chronic fatigue syndrome (CFS) have been proposed but not compared experimentally.

METHODS

We compared the cognitive task performance of FND, CFS, and healthy control (HC) groups. The tasks assessed attentional bias toward illness-relevant stimuli (visual probe task), attentional control (attention network task), and somatic interpretations (interpretative bias task), alongside self-reported depression, anxiety, fatigue, and general health.

RESULTS

Thirty-seven participants diagnosed with FND, 52 participants diagnosed with CFS, and 51 HC participants were included. Although participants with CFS showed attentional bias for illness-relevant stimuli relative to HC (t = -3.13, p = .002, d = 0.624), individuals with FND did not (t = -1.59, p = .118, d = 0.379). Both the FND (t = 3.08, p = .003, d = 0.759) and CFS (t = 2.74, p = .007, d = 0.548) groups displayed worse attentional control than did the HC group. Similarly, the FND (t = 3.63, p < .001, d = 0.801) and CFS groups (t = 4.58, p < .001, d = 0.909) showed more somatic interpretative bias than did the HC group.

CONCLUSIONS

Similar attentional control deficits and somatic interpretative bias in individuals with FND and CFS support potential shared mechanisms underlying symptoms. Interpretative bias toward somatic and illness-relevant stimuli in functional disorders may prove a therapeutic target.

Posttraumatic functional movement disorders and litigation

The concept of functional movement disorders has evolved considerably over the past few decades. More specifically, the views on the relation with psychological stressors or personality disorders have substantially changed, emphasizing a shift from the previously dominant dualistic scheme. This evolution is reflected in adaptations to diagnostic criteria and management approaches. Functional movement disorders which arise in a close temporal relationship with a peripheral trauma are specifically challenging with respect to diagnosis and treatment, but similar considerations seem to apply. The relationship of functional disorders with trauma appears to be much closer than is often thought. Clinical and pathophysiological research has identified shared factors underlying functional posttraumatic as well as primary movement disorders. These evolving insights impact on discussions in terms of litigation for compensation after trauma. The literature is reviewed and the consequences for argumentation in litigation are outlined, including ethical and legal considerations. Finally, we formulate a number of recommendations.

Functional dystonia: A case-control study and risk prediction algorithm

OBJECTIVE

Functional dystonia (FD) is a disabling and diagnostically challenging functional movement disorder (FMD). We sought to identify historical predictors of FD vs. other primary dystonias (ODs) and develop a practical prediction algorithm to guide neurologists.

METHODS

1475 consecutive new patient medical records were reviewed at an adult/pediatric tertiary-referral dystonia clinic from 2005 to 2017. Ninety-nine met criteria for clinically established FD (85 adults and 14 pediatric), paired with 99 age/dystonia distribution-matched OD. Univariate and multivariate regression analyses were performed to identify predictors of FD and disability. We formed a prediction algorithm, assessed using the area under the receiver operating curve (AUC).

RESULTS

Multivariate logistic regression analysis investigating independent predictors of FD (P < 0.001) followed by development of a prediction algorithm showed that the most robust predictors included abrupt onset, spontaneous resolution/recurrence, pain, cognitive complaints, being on or pursuing disability, lifetime mood/anxiety disorder, comorbid functional somatic disorders, and having ≥3 medication allergies. The prediction algorithm had utility for both adult and pediatric FD, with excellent sensitivity/specificity (89%/92%) and an area under the curve (AUC) 0.95 (0.92-0.98). Greater disability (modified Rankin Scale) independently correlated with a number of functional examination features, unemployment/not attending school, number of medication allergies, and younger age of presentation. FD patients were high health-care utilizers and were more frequently prescribed opiates/opioids and benzodiazepines (P < 0.003).

INTERPRETATION

This case-control study provides an algorithm to guide clinicians in gauging their index of suspicion for a FD, with diagnostic confirmation subsequently informed by neurological examination. While this algorithm requires prospective validation, health-care utilization data underscore the importance and need for more research in FD.

Neuroimaging in Functional Neurological Disorder: State of the Field and Research Agenda

Functional neurological disorder (FND) was of great interest to early clinical neuroscience leaders. During the 20th century, neurology and psychiatry grew apart - leaving FND a borderland condition. Fortunately, a renaissance has occurred in the last two decades, fostered by increased recognition that FND is prevalent and diagnosed using "rule-in" examination signs. The parallel use of scientific tools to bridge brain structure - function relationships has helped refine an integrated biopsychosocial framework through which to conceptualize FND. In particular, a growing number of quality neuroimaging studies using a variety of methodologies have shed light on the emerging pathophysiology of FND. This renewed scientific interest has occurred in parallel with enhanced interdisciplinary collaborations, as illustrated by new care models combining psychological and physical therapies and the creation of a new multidisciplinary FND society supporting knowledge dissemination in the field. Within this context, this article summarizes the output of the first International FND Neuroimaging Workgroup meeting, held virtually, on June 17th, 2020 to appraise the state of neuroimaging research in the field and to catalyze large-scale collaborations. We first briefly summarize neural circuit models of FND, and then detail the research approaches used to date in FND within core content areas: cohort characterization; control group considerations; task-based functional neuroimaging; resting-state networks; structural neuroimaging; biomarkers of symptom severity and risk of illness; and predictors of treatment response and prognosis. Lastly, we outline a neuroimaging-focused research agenda to elucidate the pathophysiology of FND and aid the development of novel biologically and psychologically-informed treatments.

Clinical Characteristics of Functional Movement Disorders in the Stomatognathic System

Background: Functional (psychogenic) movement disorders often have distinguishable clinical features in the orofacial region. Tonic mandibular deviation accompanying ipsilateral downward and lateral lip pulling is the most common phenotype seen in patients with facial functional movement disorders. However, functional movement disorders in the stomatognathic system are underrecognized. Objective: This study aimed to evaluate clinical characteristics and phenomenology in patients with functional movement disorders in the stomatognathic system. Methods: Ten-item inclusion criteria (point range: 0-10) for functional movement disorders in the stomatognathic system was produced, based on previously established criteria for functional movement disorders and general signs of functional facial dystonia, to determine subject inclusion. The criteria included inconsistency, incongruence, and paroxysm in symptoms; rapid onset; distractibility; suggestibility; static course; spreading to multiple sites; spontaneous remission; and lack of sensory tricks. Fifty-eight patients [42 women (72.4%), 16 men (27.6%); mean age: 46.2 years] scored over 7 points on the criteria and were included in further analyses. Characteristic features, including the pattern and site of abnormal movements, were assessed in clinical examination. Results: Frequent items in the scale were inconsistent symptoms (93.1%), incongruous symptoms (91.4%), spreading to multiple sites (89.7%), paroxysmal symptoms (86.2%), and lack of sensory tricks (81%). Sixty percent of patients exhibited a pattern resembling dystonia. Some patients had a combination of organic and functional disease. Common involuntary movements included jaw deviation (74.1%), jaw closing (50%), lip pulling (34.5%), and tongue movement (31%). A functional dystonia phenotype (unilateral lower lip pulling and jaw deviation) was observed in 26 patients (44.8%). Characteristic features of functional stomatognathic movement disorders were rapidly repeating mandibular (lateral or tapping) and tongue movements (27.6%), which fluctuated in speed and direction. Conclusion: In 58 patients with functional movement disorders in the stomatognathic system, the functional dystonia phenotype was observed in 44.8%. Furthermore, 27.6% of patients showed the most characteristic type of functional stomatognathic movement disorders: very fast repeated jaw and/or lingual movements.

Current Concepts in Diagnosis and Treatment of Functional Neurological Disorders

Importance

Functional neurological disorders (FND) are common sources of disability in medicine. Patients have often been misdiagnosed, correctly diagnosed after lengthy delays, and/or subjected to poorly delivered diagnoses that prevent diagnostic understanding and lead to inappropriate treatments, iatrogenic harm, unnecessary and costly evaluations, and poor outcomes.

Observations

Functional Neurological Symptom Disorder/Conversion Disorder was adopted by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, replacing the term psychogenic with functional and removing the criterion of psychological stress as a prerequisite for FND. A diagnosis can now be made in an inclusionary manner by identifying neurological signs that are specific to FNDs without reliance on presence or absence of psychological stressors or suggestive historical clues. The new model highlights a wider range of past sensitizing events, such as physical trauma, medical illness, or physiological/psychophysiological events. In this model, strong ideas and expectations about these events correlate with abnormal predictions of sensory data and body-focused attention. Neurobiological abnormalities include hypoactivation of the supplementary motor area and relative disconnection with areas that select or inhibit movements and are associated with a sense of agency. Promising evidence has accumulated for the benefit of specific physical rehabilitation and psychological interventions alone or in combination, but clinical trial evidence remains limited.

Conclusions and Relevance

Functional neurological disorders are a neglected but potentially reversible source of disability. Further research is needed to determine the dose and duration of various interventions, the value of combination treatments and multidisciplinary therapy, and the therapeutic modality best suited for each patient.