Cranial functional (psychogenic) movement disorders

Opsoclonus Induced by Head-Shaking in Vestibular Migraine

Opsoclonus refers to saccadic oscillations without an intersaccadic interval occurring in multiple planes. Opsoclonus mostly indicates dysfunction of the brainstem or cerebellum. We report opsoclonus induced by horizontal head-shaking without other signs of brainstem or cerebellar dysfunction in two patients with vestibular migraine (VM). The development of opsoclonus after horizontal head-shaking indicates unstable or hyperactive neural circuits between the excitatory and inhibitory saccadic premotor burst neurons in these patients with VM.

The etiology, diagnostics, and treatment of the spasm of the near reflex - a narrative review

Physiological adaptation of the eye to the visual perception of near objects consists of the "near triad": convergence, accommodation, and pupil miosis. Normally, these tend to revert when one stops fixating on a near object. Spasm of the near reflex (SNR) is a pathological phenomenon, which manifests itself by the persistence of the above-mentioned adjustments, which prevents the eye from returning to its relaxed state. In this narrative review, we aim to summarize the etiology, diagnostics, treatment, and prevention of SNR. The literature review was performed by searching online databases. The clinical presentation of SNR is diverse; it presents as isolated accommodative spasm more frequently than impairment of all three components of the near triad. Patients usually present with fluctuations in visual acuity, blurred vision, diplopia, and asthenopia. The etiology is not fully understood. Potential causes include neuroanatomic, organic, and psychogenic disorders. The diagnosis is clinical, based on the constellation of symptoms and assessment of the near triad. The diagnostic golden standard is a cycloplegic examination of refraction, preferably using cyclopentolate hydrochloride (1%, 0.5%, or 0.1% solution). The first-line treatment requires the administration of a cycloplegic drug in combination with plus lenses, flipper lenses, optical fogging, or miotics. For secondary cases, causal treatment should be implemented. Prevention of SNR should be based on eliminating modifiable risk factors. We propose including screening for SNR symptoms in every ophthalmic examination, especially among patients with psychogenic or neural disorders, after brain trauma, or young adults spending much time in front of computer screens.

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.

Chronic mimics of myasthenia gravis: a retrospective case series

Myasthenia gravis often presents a diagnostic challenge and may be misdiagnosed, particularly in seronegative disease with active symptoms. We retrospectively evaluated 61 patients following the introduction of single fibre electromyography at our service, and identified 8 mimics which had been inappropriately diagnosed and treated as refractory myasthenia gravis. 6 of these were seronegative, but two had positive acetylcholine receptor (AChR) antibodies. The final diagnoses included one case each of chronic progressive external ophthalmoplegia, chronic ptosis, oculopharyngeal muscular dystrophy, and an undifferentiated disorder suspicious for either a mitochondrial cytopathy or low-grade myositis. Four were diagnosed with functional neurological disorder, one of which had a superimposed thyroid myopathy and orbitopathy. We found the average duration of misdiagnosis was 9 years (SD±5.2, median 11 years), and patients were often exposed to years of unnecessary treatment. All patients had received anticholinesterase therapy, three had immunotherapy, and three surgical interventions were performed including two thymectomies. We found myasthenic mimics should be suspected in disease that is static and treatment refractory, and functional mimics in disease with frequent flares. Thorough neurophysiologic assessment is important, particularly when making a diagnosis of seronegative myasthenia gravis.

Acute comitant strabismus in anti-GQ1b antibody syndrome

Ophthalmoplegia is the diagnostic hallmark of anti-GQ1b antibody syndrome. This study aimed to define the patterns of acute comitant strabismus in patients with anti-GQ1b antibody syndromes. We retrospectively analyzed the ocular motor findings in 84 patients with anti-GQ1b antibody-associated ophthalmoplegia during the acute phases. Of the 84 patients, 11 (13%) showed acute comitant strabismus. Compared to those without, patients with acute comitant strabismus frequently showed abnormal ocular motor findings that included gaze-evoked (n = 8), spontaneous (n = 4) and positional nystagmus (n = 4), saccadic hypermetria (n = 3), head-shaking nystagmus (n = 2), pulse-step mismatch (n = 1), and impaired visual cancellation of the vestibulo-ocular reflex (n = 1, p < 0.001). On the contrary, iridoplegia (p = 0.029) and ptosis (p = 0.001) were more commonly observed in patients with paralytic (incomitant) strabismus than in those with acute comitant strabismus. Comitant strabismus can manifest during the acute phase of anti-GQ1b antibody syndromes in association with other central ocular motor abnormalities. These findings implicate that the cerebellum and/or brainstem can be the primary target of the anti-GQ1b antibodies.

Dysfunctional Networks in Functional Dystonia

Functional dystonia, the second most common functional movement disorder, is characterized by acute or subacute onset of fixed limb, truncal, or facial posturing, incongruent with the action-induced, position-sensitive, and task-specific manifestations of dystonia. We review neurophysiological and neuroimaging data as the basis for a dysfunctional networks in functional dystonia. Reduced intracortical and spinal inhibition contributes to abnormal muscle activation, which may be perpetuated by abnormal sensorimotor processing, impaired selection of movements, and hypoactive sense of agency in the setting of normal movement preparation but abnormal connectivity between the limbic and motor networks. Phenotypic variability may be related to as-yet undefined interactions between abnormal top-down motor regulation and overactivation of areas implicated in self-awareness, self-monitoring, and active motor inhibition such as the cingulate and insular cortices. While there remain many gaps in knowledge, further combined neurophysiological and neuroimaging assessments stand to inform the neurobiological subtypes of functional dystonia and the potential therapeutic applications.

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.

Understanding, Recognizing, and Managing Functional Speech Disorders: Current Thinking Illustrated With a Case Series

PURPOSE

Functional speech disorders (FSDs), a subtype of functional neurological disorders, are distinguishable from neurogenic motor speech disorders based on their clinical features, clinical course, and response to treatment. However, their differential diagnosis and management can be challenging. FSDs are not well understood, but growing evidence suggests a biopsychosocial basis distinct from structural lesions that cause neurogenic motor speech disorders.

METHOD AND RESULTS

Following an overview of FSDs, four patients are described to illustrate the range of clinical manifestations, biopsychosocial contexts, and responses to treatment of FSDs. The path to differential diagnosis is discussed, with particular attention to positive features that led to the FSD diagnosis. Approaches to education, counseling, and management are discussed.

CONCLUSIONS

This case series demonstrates that FSDs can present with a variety of manifestations including dysfluencies, articulation errors, dysphonia, rate and prosodic abnormalities, and combinations of disruptions in speech subsystems. FSDs may present in the context of known recent or remote physical or psychosocial trauma or, as in many cases, in the absence of an identifiable triggering event. FSDs are recognizable by positive clinical features and should not be considered a diagnosis of exclusion. With appropriate identification, counseling, and treatment, FSDs may resolve, sometimes rapidly; in some cases, treatment may be prolonged or ineffective.

Triggers in functional motor disorder: a clinical feature distinct from precipitating factors

Background and objective

People with functional motor disorder (FMD) report triggers—sensory or motor-induced stimuli that exacerbate or initiate paroxysmal occurrences of their movement disorder. These are a distinct phenomenon from precipitating factors occurring at the initial onset of the disorder. We aimed to assess triggers in FMD and understand their relevance to paroxysmal variability often seen in FMD.

Methods

We enrolled consecutive outpatients with a definite diagnosis of FMD. Each patient underwent a detailed clinical evaluation also including the presence of trigger factors and video-recordings both during neurological examination and physiotherapy treatment. Patients were classified as having “triggers” (T-FMD) or “not having triggers” (NoT-FMD) as well as “paroxysmal” compared to “persistent with paroxysmal variability”.

Results

The study sample was 100 patients (82% female) with FMD; the mean age at onset was 41 years. Triggers were observed in 88% of patients and in 65 of these the FMD was pure paroxysmal. The most common triggers were movement or physical exercise, followed by emotional, visual, touch, and auditory stimuli; 39 (44%) were isolated and 49 (56%) were combined triggers. Among the T-FMD patients, FMD were paroxysmal in 74% (n = 65) and persistent with paroxysmal variability in 26% (n = 23). The T-FMD patients were younger (p = 0.016) and had a gait disorder (p = 0.035) more frequently than the NoT-FMD patients.

Discussion

Triggers are frequent in FMD and may have diverse overlapping clinical presentations. In this sample, FMD was most often paroxysmal, suggesting the value of noting triggers as clinical clues in the diagnosis and rehabilitation of FMD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11102-1.

Botulinum Toxin Therapy for Oromandibular Dystonia and Other Movement Disorders in the Stomatognathic System

Various movement disorders, such as oromandibular dystonia, oral dyskinesia, bruxism, functional (psychogenic) movement disorder, and tremors, exist in the stomatognathic system. Most patients experiencing involuntary movements due to these disorders visit dentists or oral surgeons, who may be the first healthcare providers. However, differential diagnoses require neurological and dental knowledge. This study aimed to review scientific advances in botulinum toxin therapy for these conditions. The results indicated that botulinum toxin injection is effective and safe, with few side effects in most cases when properly administered by an experienced clinician. The diagnosis and treatment of movement disorders in the stomatognathic system require both neurological and dental or oral surgical knowledge and skills, and well-designed multicenter trials with a multidisciplinary team approach must be necessary to ensure accurate diagnosis and proper treatment.

Eye Movement Disorders in Movement Disorders

Oculomotor assessment is an essential element of the neurological clinical examination and is particularly important when evaluating patients with movements disorders. Most of the brain is involved in oculomotor control, and thus many neurological conditions present with oculomotor abnormalities. Each of the different classes of eye movements and their features can provide important information that can facilitate differential diagnosis. This educational review presents a clinical approach to eye movement abnormalities that are commonly seen in parkinsonism, ataxia, dystonia, myoclonus, tremor, and chorea. In parkinsonism, subtle signs such as prominent square wave jerks, impaired vertical optokinetic nystagmus, and/or the "round the houses" sign suggest early progressive supranuclear gaze palsy before vertical gaze is restricted. In ataxia, nystagmus is common, but other findings such as oculomotor apraxia, supranuclear gaze palsy, impaired fixation, or saccadic pursuit can contribute to diagnoses such as ataxia with oculomotor apraxia, Niemann-Pick type C, or ataxia telangiectasia. Opsoclonus myoclonus and oculopalatal myoclonus present with characteristic phenomenology and are usually easy to identify. The oculomotor exam is usually unremarkable in isolated dystonia, but oculogyric crisis is a medical emergency and should be recognized and treated in a timely manner. Gaze impersistence in a patient with chorea suggests Huntington's disease, but in a patient with dystonia or tremor, Wilson's disease is more likely. Finally, functional eye movements can reinforce the clinical impression of a functional movement disorder.

Diagnosis and management of functional neurological disorder

Functional neurological disorder (FND), previously regarded as a diagnosis of exclusion, is now a rule-in diagnosis with available treatments. This represents a major step toward destigmatizing the disorder, which was often doubted and deemed untreatable. FND is prevalent, generally affecting young and middle aged adults, and can cause severe disability in some individuals. An early diagnosis, with subsequent access to evidence based rehabilitative and/or psychological treatments, can promote recovery-albeit not all patients respond to currently available treatments. This review presents the latest advances in the use of validated rule-in examination signs to guide diagnosis, and the range of therapeutic approaches available to care for patients with FND. The article focuses on the two most frequently identified subtypes of FND: motor (weakness and/or movement disorders) and seizure type symptoms. Twenty two studies on motor and 27 studies on seizure type symptoms report high specificities of clinical signs (64-100%), and individual signs are reviewed. Rehabilitative interventions (physical and occupational therapy) are treatments of choice for functional motor symptoms, while psychotherapy is an emerging evidence based treatment across FND subtypes. The literature to date highlights heterogeneity in responses to treatment, underscoring that more research is needed to individualize treatments and develop novel interventions.

Periorbital injections of botulinum toxin a: a novel therapeutic option for convergence spasm in neuropsychiatric disorders

PURPOSE

Convergence spasm (CS, spasm of near reflex) is characterized by transient attacks of convergence, miosis and accommodation, often associated with functional neurological disorders. To date, no simple and efficient treatment option is available for CS. This study investigates whether periorbital botulinum toxin injections as used in essential blepharospasm are also a treatment option in these patients.

METHODS

All patients with convergence spasm having been treated with periorbital BoNTA injections in the department of neuro-ophthalmology were identified. Data were extracted from patient files concerning details and subjective effectiveness of botulinum toxin injections and relation to psychiatric or neurological disorders. Patients reporting with a history of closed-head trauma or organic neurologic pathologies possibly causing CS were excluded. A telephone assessment with a standardized questionnaire was performed to evaluate mental health issues as a trigger, as well as the long-term effect and satisfaction with periorbital injections.

RESULTS

Of 16 patients treated with periorbital botulinum toxin injections for convergence spasm, 9 patients reported depression and/or anxiety disorders ongoing or in the past. A median number of 3 injections (range 1-13) was administered with a variable effect (relief of symptoms) between no effect and effect of up to more than 12 weeks. A longitudinal follow-up revealed ongoing symptoms in five patients.

CONCLUSIONS

Periorbital botulinum toxin injections are less invasive than injections in the medial rectus muscle and can be a bridging therapeutic option in patients with CS. Mental health exploration is important due to psychiatric comorbidity.

Design and Preliminary Evaluation of a Tongue-Operated Exoskeleton System for Upper Limb Rehabilitation

Stroke is a devastating condition that may cause upper limb paralysis. Robotic rehabilitation with self-initiated and assisted movements is a promising technology that could help restore upper limb function. Previous studies have established that the tongue motion can be used to communicate human intent and control a rehabilitation robot/assistive device. The goal of this study was to evaluate a tongue-operated exoskeleton system (TDS-KA), which we have developed for upper limb rehabilitation. We adopted a tongue-operated assistive technology, called the tongue drive system (TDS), and interfaced it with the exoskeleton KINARM. We also developed arm reaching and tracking tasks, controlled by different tongue operation modes, for training and evaluation of arm motor function. Arm reaching and tracking tasks were tested in 10 healthy participants (seven males and three females, 23-60 years) and two female stroke survivors with upper extremity impairment (32 and 58 years). All healthy and two stroke participants successfully performed the tasks. One stroke subject demonstrated a clinically significant improvement in Fugl-Meyer upper extremity score after practicing the tasks in six 3-h sessions. We conclude that the TDS-KA system can accurately translate tongue commands to exoskeleton arm movements, quantify the function of the arm, and perform rehabilitation training.

Decade of progress in motor functional neurological disorder: continuing the momentum

Functional neurological disorder (FND) is a prevalent, disabling and costly condition at the neurology-psychiatry intersection. After being marginalised in the late 20th century, there has been renewed interest in this field. In this article, we review advances that have occurred over the past decade (2011-2020) across diagnosis, mechanisms, aetiologies, treatments and stigma in patients with motor FND (mFND, that is, functional movement disorder and functional limb weakness). In each content area, we also discuss the implications of recent advances and suggest future directions that will help continue the momentum of the past decade. In diagnosis, a major advance has been the emphasis on rule-in physical signs that are specific for hyperkinetic and hypokinetic functional motor symptoms. Mechanistically, greater importance has been given to determining 'how' functional neurological symptoms develop, highlighting roles for misdirected attention, expectation and self-agency, as well as abnormal influences of emotion/threat processing brain areas on motor control circuits. Aetiologically, while roles for adverse life experiences remain of interest in mFND, there is recognition of other aetiologic contributors, and efforts are needed to investigate links between aetiological factors and mechanisms. This decade has seen the first randomised controlled trials for physiotherapy, multidisciplinary rehabilitation and psychotherapy performed in the field, with consensus recommendations for physiotherapy, occupational therapy and outcome measures also published. Across patients, clinicians, healthcare systems and society, stigma remains a major concern. While challenges persist, a patient-centred integrated clinical neuroscience approach is primed to carry forward the momentum of the past decade into the future.

A practical review of functional neurological disorder (FND) for the general physician

We present a practical overview of functional neurological disorder (FND), its epidemiology, assessment and diagnosis, diagnostic pitfalls, treatment, aetiology and mechanism. We present an update on functional limb weakness, tremor, dystonia and other abnormal movements, dissociative seizures, functional cognitive symptoms and urinary retention, and 'scan-negative' cauda equina syndrome. The diagnosis of FND should rest on clear positive evidence, typically from a combination of physical signs on examination or the nature of seizures. In treatment of FND, clear communication of the diagnosis and the involvement of the multidisciplinary team is beneficial. We recommend that patients with FND are referred to specialists with expertise in neurological diagnosis. FND is a common presentation in emergency and acute medical settings and there are many practical elements to making a positive diagnosis and communication which are useful for all physicians to be familiar with.

Towards an Outpatient Model of Care for Motor Functional Neurological Disorders: A Neuropsychiatric Perspective

Functional neurological disorder (FND), a condition at the intersection of neurology and psychiatry, is a common and disabling outpatient referral to neurology and neuropsychiatry clinics. In this perspective article, we focus on the motor spectrum of FND (mFND), including individuals with functional movement disorders (FND-movt), functional limb weakness/paresis (FND-par) and functional [psychogenic non-epileptic/dissociative] seizures (FND-seiz). Over the past several decades, there have been dedicated efforts within the neurologic and psychiatric communities to create "rule-in" diagnostic criteria, as well as thoughtful approaches to the clinical interview, delivery of the diagnosis and the development of a patient-centered treatment plan. These advances allow the promotion of good clinical practices in the outpatient assessment and management of mFND. Informed by the literature and our prior clinical experiences, we provide suggestions on how to evaluate individuals with suspected functional motor symptoms - including conducting sensitive psychiatric and psychosocial screenings. Additional sections discuss common "rule-in" neurological examination and semiologic signs of motor FND, as well as approaches to deliver the diagnosis and formulate a treatment plan based on individual patient needs. To aid the development of shared (partially overlapping) expertise that catalyzes an interdisciplinary approach to mFND, the use of physiotherapy for therapeutic motor retraining and cognitive behavioral therapy to examine relationships between symptoms, thoughts, behaviors and emotions are also discussed. Additional clinical research is needed to further refine and operationalize the assessment and management of mFND, across clinics, healthcare settings and countries.

Cranial Functional Movement Disorders: A Case Series with Literature Review

Background:

Cranial functional movement disorders (CFMDs) affect the face, eyes, jaw, tongue, and palate.

Objectives:

We aimed to examine our large series of functional movement disorders (FMDs) patients where the cranial muscles were involved to determine their phenomenology and other clinical features.

Methods:

This is a chart review of 26 patients who presented with CFMDs.

Results:

There were 16 (61.53%) females and 10 (38.46%) male patients. The mean ± [standard deviation (SD)] age at the presentation was 33.96 ± 16.94 (Range: 11–83) years. The duration of symptoms ranged from one day to 6 years (Mean ±SD: 402.03 ±534.97 days). According to the Fahn-Williams criteria, CFMDs were documented in 24 patients and clinically established in two patients. The facial [38.46% (10/26)] involvement was the most common in our CFMDs patients. Oromandibular [19.23% (5/26)], ocular [15.38% (4/26)], lingual [15.38% (4/26)], speech [15.38% (4/26)] and palatal [(3.85; 1/26)] involvement was also seen. 10 (38.46%) patients also had associated FMD in the extracranial regions. Precipitating factors were present in 84.61% (22/26) of the patients and associated illnesses were present in 42.30% (11/26) of the patients. At 3 months follow-up, 9 (34.61%) patients had improved, 13 (50%) had partial improvement and 4 (15.38%) had no improvement.

Conclusions:

There was a slight female preponderance in our patients. CFMDs are more likely to involve facial muscles. Associated medical conditions like neuropsychiatric disturbances and headaches are frequently present in CFMDs patients. Early clinical diagnosis will avoid unnecessary investigations and allow the patient to seek the right treatment.

Functional positional eye and eyelid movements

BACKGROUND

Positional manoeuvres are an important part of the neurological examination, particularly in patients with vertigo where the presence and characteristics of provoked nystagmus can help differentiate central from peripheral neurological disorders.

METHODS

Case series of functional positional eye and eyelid movements.

RESULTS

We report four patients with functional eye and eyelid movements provoked during positional manoeuvres. The range of abnormalities observed included positional convergence spasm, brief functional saccadic oscillations, and excessive positional blinking mimicking upbeat nystagmus. The functional movements described were present on a background of pre-existing peripheral or central nystagmus, or positional vertigo.

CONCLUSION

Functional positional eye and eyelid movements may co-exist with organic nystagmus that renders an accurate interpretation of the manoeuvre more challenging. A thorough understanding of the clinical features that differentiate these two categories of eye/eyelid movements makes the analysis easier, thus preventing misdiagnosis and avoiding unnecessary investigations.

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.

Diagnosis of Accommodative Spasm Aided by Handheld Photoscreener

We report a case of accommodative spasm in an 8-year-old girl discovered by handheld photoscreener. The patient was found to have a Chiari I malformation, and managed with atropine drops and reading glasses, ultimately with improvement in her symptoms. We believe this to be the first case of accommodative spasm diagnosis aided by the use of a handheld photoscreener.

Psychogenic (Functional) Movement Disorders

PURPOSE OF REVIEW

This article reviews a practical approach to psychogenic movement disorders to help neurologists identify and manage this complex group of disorders.

RECENT FINDINGS

Psychogenic movement disorders, also referred to as functional movement disorders, describe a group of disorders that includes tremor, dystonia, myoclonus, parkinsonism, speech and gait disturbances, and other movement disorders that are incongruent with patterns of pathophysiologic (organic) disease. The diagnosis is based on positive clinical features that include variability, inconsistency, suggestibility, distractibility, suppressibility, and other supporting information. While psychogenic movement disorders are often associated with psychological and physical stressors, the underlying pathophysiology is not fully understood. Although insight-oriented behavioral and pharmacologic therapies are helpful, a multidisciplinary approach led by a neurologist, but also including psychiatrists and physical, occupational, and speech therapists, is needed for optimal outcomes.

SUMMARY

The diagnosis of psychogenic movement disorders is based on clinical features identified on neurologic examination, and neurophysiologic and imaging studies can provide supporting information.

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.

Abnormal Eye and Cranial Movements Triggered by Examination in People with Functional Neurological Disorder

The diagnosis of functional neurological disorder (FND) relies on the demonstration of positive symptoms and signs, as supported by recent changes in DSM5. We recorded the findings of routine clinical eye movement assessment in 101 consecutive new patients with FND. Clinical examination triggered facial and eye movement disorders in 46% of patients, all with positive characteristics of functional movement disorder. These are useful as supporting features in making a positive diagnosis of FND.

Pathogenesis and pathophysiology of functional (psychogenic) movement disorders

Functional movement disorders (FMDs), known over time as "hysteria", "dissociative", "conversion", "somatoform", "non-organic" and "psychogenic" disorders, are characterized by having a voluntary quality, being modifiable by attention and distraction but perceived by the patient as involuntary. Although a high prevalence of depression and anxiety is observed in these patients, a definitive role of psychiatric disorders in FMDs has not been proven, and many patients do not endorse such manifestations. Stressful events, social influences and minor trauma may precede the onset of FMDs, but their pathogenic mechanisms are unclear. Patients with FMDs have several abnormalities in their neurobiology including strengthened connectivity between the limbic and motor networks. Additionally, there is altered top-down regulation of motor activities and increased activation of areas implicated in self-awareness, self-monitoring, and active motor inhibition such as the cingulate and insular cortex. Decreased activation of the supplementary motor area (SMA) and pre-SMA, implicated in motor control and preparation, is another finding. The sense of agency defined as the feeling of controlling external events through one's own action also seems to be impaired in individuals with FMDs. Correlating with this is a loss of intentional binding, a subjective time compression between intentional action and its sensory consequences. Organic and functional dystonia may be difficult to differentiate since they share diverse neurophysiological features including decreased cortical inhibition, and similar local field potentials in the globus pallidus and thalamus; although increased cortical plasticity is observed only in patients with organic dystonia. Advances in the pathogenesis and pathophysiology of FMDs may be helpful to understand the nature of these disorders and plan further treatment strategies.

Adult Periodic Alternating Nystagmus Masked by Involuntary Head Movements

Acquired periodic alternating nystagmus (PAN) describes a horizontal jerk nystagmus that reverses its direction with a predictable cycle, and is thought to arise from lesions involving the brainstem and cerebellum. We report a 20-year-old patient with PAN who presented with an acute vertiginous episode and developed an involuntary head movement that initially masked the PAN. The involuntary head movements were abolished with a subtherapeutic dose of botulinum toxin to the neck muscles. We propose that the head movements initially developed as a compensatory movement to the nystagmus, to maintain visual fixation in the presence of the underlying nystagmus, and became an entrained involuntary behavior. This case highlights the importance of disambiguating psychogenic from organic pathology as this may have clinical therapeutic implications, in this case resolution of the most disabling symptom which was her head oscillations, leading to improved day-to-day function despite PAN.

Spasm of the near reflex: A case report

Purpose

Spasm of the near reflex (SNR) is a triad of miosis, excess accommodation and excess convergence. Primary SNR is most often functional in origin We aim to highlight the clinical features which distinguish primary convergence from other conditions with a similar presentation but more sinister underlying aetiology, for example bilateral abducens nerve palsy.

Observations

There is a paucity of published data on SNR, in particular diagnostic criteria and treatment. We report a case of SNR of functional origin in an otherwise healthy young female and discuss the clinical features that differentiate this condition from similar conditions with underlying neurological origin.

Conclusions and importance

SNR is predominantly a clinical diagnosis, and often leads to patients undergoing unnecessary investigations and sometimes treatment. Recognising the salient features that differentiate it could potentially avoid this.

Functional dystonia and the borderland between neurology and psychiatry: New concepts

Mind-brain dualism has dominated historical commentary on dystonia, a dichotomous approach that has left our conceptual grasp of it stubbornly incomplete. This is particularly true of functional dystonia, most diagnostically challenging of all functional movement disorders, in which the question of inherent psychogenicity remains a focus of debate. Phenomenological signs considered in isolation lack the specificity to distinguish organic and nonorganic forms, and dystonia's variability has frustrated attempts to develop objective laboratory-supported standards. Diagnostic criteria for functional dystonia that place emphasis on psychiatric symptoms perform poorly in studies of reliability, partly explained by the high frequency of psychopathology in organic dystonia. Novel approaches from the cognitive neurosciences may offer a way forward. Theory on Bayesian statistical prediction in cognitive processing is supported by sufficient experimental evidence for this model to be taken seriously as a way of reconciling contradictory notions about voluntary and unconscious motor control in functional movement disorders. In a Bayesian formulation of functional dystonia, misallocation of attention and abnormal predictive beliefs generate movements that are executed without a sense of agency. Building on this framework, there is a consensus that a biopsychosocial approach is required and that a unified philosophy of brain and mind is the best way to locate dystonia in the neurology-psychiatry borderland. At a practical level, movement disorder neurologists are best placed to differentiate organic from functional dystonia. The main role of psychiatrists is in the diagnosis and management of the primarily psychiatric disorders that often accompany dystonia. © 2016 International Parkinson and Movement Disorder Society.

Functional limb weakness and paralysis

Functional (psychogenic) limb weakness describes genuinely experienced limb power or paralysis in the absence of neurologic disease. The hallmark of functional limb weakness is the presence of internal inconsistency revealing a pattern of symptoms governed by abnormally focused attention. In this chapter we review the history and epidemiology of this clinical presentation as well as its subjective experience highlighting the detailed descriptions of authors at the end of the 19th and early 20th century. We discuss the relevance that physiological triggers such as injury and migraine and psychophysiological events such as panic and dissociation have to understanding of mechanism and treatment. We review many different positive diagnostic features, their basis in neurophysiological testing and present data on sensitivity and specificity. Diagnostic bedside tests with the most evidence are Hoover's sign, the hip abductor sign, drift without pronation, dragging gait, give way weakness and co-contraction.

Functional eye movement disorders

Functional (psychogenic) eye movement disorders are perhaps less established in the medical literature than other types of functional movement disorders. Patients may present with ocular symptoms (e.g., blurred vision or oscillopsia) or functional eye movements may be identified during the formal examination of the eyes in patients with other functional disorders. Convergence spasm is the most common functional eye movement disorder, but functional gaze limitation, functional eye oscillations (also termed "voluntary nystagmus"), and functional convergence paralysis may be underreported. This chapter reviews the different types of functional eye movement abnormalities and provides a practical framework for their diagnosis and management.