Psychogenic Movement Disorders Research Articles

Conversion Disorder and Its Clinical Management

This review discusses the complex path to the current definition of conversion disorder (CD), from ancient Egypt to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), and the way that our understanding of the disorder’s etiology and pathophysiology shaped both its name and its diagnostic criteria. We describe emergence of a comprehensive theory of CD’s pathophysiology, in which an overly sensitive limbic system, shaped by traumatic experiences, changes neural networks responsible for perceptual experiences and movement plans, ultimately producing CD symptoms. We also discuss the importance of early diagnosis of CD as a delayed diagnosis is associated with worse outcomes and precludes appropriate treatment. A variety of diagnostic techniques exist to help distinguish between functional neurologic symptoms and organic disease. Among treatments, we highly recommend therapeutic disclosure of the diagnosis and cognitive-behavioral therapy, which has a small but high-quality evidence base to support its use in the treatment of CD. Collaboration between psychiatrists and neurologists may ensure appropriate diagnosis and treatment of this challenging condition. Prognosis of CD is generally poor, with comorbid personality disorder and delayed diagnosis correlating with worse outcomes. This review contains 4 figures, 6 tables, and 86 references. Key words: conversion disorder, functional neurologic disorder, hysteria, medically unexplained symptoms, psychogenic movement disorder, psychogenic nonepileptic seizures

Clinical and neural responses to cognitive behavioral therapy for functional tremor.

To evaluate changes in tremor severity and motor/emotion-processing circuits in response to cognitive behavioral therapy (CBT) delivered as treatment for functional tremor (FT), the most common functional movement disorder in adults. Fifteen patients with FT underwent fMRI with motor, basic-emotion, and intense-emotion tasks before and after 12 weeks of CBT. Baseline fMRI was compared to those of 25 healthy controls (HCs). The main clinical endpoint was the tremor score (sum of severity, duration, and incapacitation subscores) adapted from the Rating Scale for Psychogenic Movement Disorders (PMDRS) assessed by a blinded clinician. CBT responders were defined as those with PMDRS score reduction >75%. Anatomic and functional brain images were obtained with a 4T MRI system. Generalized linear model and region-of-interest analyses were used to evaluate before-versus-after treatment-related changes in brain activation. CBT markedly reduced tremor severity (p < 0.01) with remission/near remission achieved in 73.3% of the cohort. Compared to HCs, in those with FT, a functionally defined fMRI region of interest in the anterior cingulate/paracingulate cortex showed increased activation at baseline and decreased activation after CBT during basic-emotion processing (p = 0.012 for CBT responders). Among CBT responders, the change in anterior cingulate/paracingulate was more significant in those with more severe baseline depression (r = 0.75, p < 0.01). Tremor severity improved significantly after CBT. The improvement was associated with changes in the anterior cingulate/paracingulate activity, which may represent a marker of emotional dysregulation in FT and a predictor of treatment response. This study provides Class III evidence that CBT significantly improves tremor severity in patients with functional tremor.

Repetitive transcranial magnetic stimulation for functional tremor: A randomized, double-blind, controlled study.

The objective of this study was to compare the effect on functional tremor of active versus sham repetitive transcranial magnetic stimulation and investigate whether the addition of hypnosis might help to prolong any repetitive transcranial magnetic stimulation-induced therapeutic effect. We compared the effect of 5 consecutive daily sessions of active/sham repetitive transcranial magnetic stimulation on functional tremor, at 1 and 2 months, in a randomized, double-blind, 2-arm, parallel-controlled study. In a second open-label phase, all patients underwent 3 weekly sessions of hypnosis combined with single sessions of real repetitive transcranial magnetic stimulation. The primary outcome was a change in the Psychogenic Movement Disorder Rating Scale at month 1 when compared with baseline. Secondary outcomes were changes in the Psychogenic Movement Disorder Rating Scale and Tremor subscores, the 36-item Short Form Health Survey, the Self-Report Hospital Anxiety and Depression Scale, the Hamilton Depression Rating Scale, and the Clinical Global Impression Scale assessed at months 1, 2, 6, and 12. A total of 33 outpatients affected by functional tremor were screened, and 18 outpatients fulfilling the inclusion criteria (8 men, 10 women) were randomized. One month after the intervention, the mean Psychogenic Movement Disorder Rating Scale score had decreased in both groups, but the differences from baseline were only significant in the active repetitive transcranial magnetic stimulation group (P < .001). This remained significant at month 2 (P < .001). The significant decrease of the Psychogenic Movement Disorder Rating Scale and Tremor subscores were maintained at months 6 and 12 for the active repetitive transcranial magnetic stimulation group. For the control group, the Psychogenic Movement Disorder Rating Scale score had returned almost to its baseline value by month 2 and remained unchanged at months 6 and 12. Repetitive transcranial magnetic stimulation could represent a valuable therapeutic option in the management of functional tremor. © 2019 International Parkinson and Movement Disorder Society.

A physical therapy programme for functional motor symptoms: A telemedicine pilot study

Introductionfor a proportion of patients with functional motor symptoms (FMS), specific physiotherapy has recently emerged as a promising treatment. Aim of the present study was to assess in a sample of patients with FMS the efficacy of a physical therapy-based telemedicine programme on the motor symptoms themselves and on some psychological variables such as anxiety, depression, alexithymia and quality of life. Materials and methodseighteen patients were recruited. The programme consisted of 24 sessions: three face-to-face sessions (at week 0 (T0), 12 (T1) and 24 (T2)) and 21 tele-sessions. Each session included education, movement retraining exercises and development of a management plan. All patients underwent the following assessment at T0, T1 and T2: Psychogenic movement disorders rating scale (PMDRS), assessment of depression, anxiety, alexithymia and quality of life. Self-assessment of outcome (CGI) was recorded at T1 and T2. ResultsOn the CGI improvement was reported by 66,7% of patients at T1 and 77,8% at T2. A significant improvement over the three time points was shown for PMDRS and for the following domains of the SF-36: general health, vitality, social functioning and mental health. Conclusionthe use of two innovative approaches for FMS (physiotherapy and telemedicine), combined together, might have a valuable role in the treatment of this neuropsychiatric condition.

Adult-Onset Gilles de la Tourette Syndrome: Psychogenic or Organic? The Challenge of Abnormal Neurophysiological Findings

Gilles de la Tourette syndrome (GTS) is characterized by multiple motor and vocal tics. Adult-onset cases are rare and may be due to “reactivation” of childhood tics, or secondary to psychiatric or genetic diseases, or due to central nervous system lesions of different etiologies. Late-onset psychogenic motor/vocal tics resembling GTS have been described. Neurophysiology may serve to differentiate organic from functional GTS. Altered blink reflex pre-pulse inhibition (BR-PPI), blink reflex excitability recovery (BR-ERC), and short-interval intracortical inhibition (SICI) have been described in GTS. We report a 48-years-old male, who developed numerous motor/vocal tics 2 months after sustaining non-commotional craniofacial trauma in a car accident. Both his father and brother had died earlier in car crashes. He presented with blepharospasm-like forced lid closure, forceful lip pursing, noisy suction movements, and deep moaning sounds, occurring in variable combinations, without warning symptoms or internal “urge.” Tics showed low distractibility and these increased with attention. Standard magnetic resonance imaging, electroencephalography, and evoked potentials were unremarkable. Neuropsychology diagnosed moderately impaired intellect, attention, and executive functions. Psychiatric assessment revealed somatization disorder and generalized anxiety. BR-PPI was unremarkable, while BR-ERC was enhanced, even showing facilitation at short intervals. SICI was markedly reduced at 1 and 3 ms and intracortical facilitation (ICF) was enhanced at 10 ms. The patient fulfilled Fahn and Williams' diagnostic criteria for a psychogenic movement disorder. Neurophysiology, however, documented hyperexcitability of motor cortex and brainstem. We suggest that—similar to what has been reported in psychogenic dystonia—a pre-existing predisposition may have led to the functional hyperkinetic disorder in response to severe psychic stress.

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.

OnabotulinumtoxinA and cognitive behavioral therapy in functional dystonia: A pilot randomized clinical trial

IntroductionFunctional dystonia (FD) is a disabling movement disorder with limited therapeutic options. We aimed to examine the efficacy and safety of chemodenervation with OnabotulinumtoxinA (BoNT) versus placebo prior to cognitive behavioral therapy (CBT) in FD patients. MethodsFD patients with a Psychogenic Movement Disorders Rating Scale (PMDRS) score ≥ 10 and persistent dystonic posturing for ≥ 1 year were randomized to BoNT or placebo injections prior to 12 weekly individualized 1-h CBT sessions. Clinical assessments included PMDRS, Hamilton Depression Scale (HAM-D), Hamilton Anxiety Scale (HAM-A), Katz index of independence in activities of daily living (ADL), and Lawton instrumental ADL (iADL). The efficacy endpoints were the change in clinical assessments at 12 weeks from baseline between and within groups. ResultsOf 18 screened patients, 14 were randomized, and 10 completed the study. All patients showed reductions in PMDRS irrespective of treatment group at the end of the follow-up period. There was no difference in clinical assessments between groups at 12 weeks. Change from baseline in PMDRS score was significantly improved only in the CBT group with prior administration of placebo (mean change −9.0, 95% CI -16.5, −1.5; p = 0.02). ConclusionsCBT yielded robust improvement in FD patients but was unaffected by prior administration of BoNT. These pilot data do not eliminate the potential for examining future BoNT benefit in FD patients with selected topographical involvement, such as face or neck.

Exploratory analyses on racial differences in diurnal cortisol and risk-taking behavior in gambling disorder

Patients affected by functional (psychogenic) movement disorders (FMD) have abnormal processing of stress responses. However, little is known about the influence of this abnormal stress processing on automatic motor defense behavior, such as freeze response. Our aim was thus to investigate stress-induced postural motor responses in FMD.Nine FMD patients and thirteen healthy controls were engaged in the Trier Social Stress Test, while we measured the movement of their body by means of accelerometers and gyroscopes attached to the thorax. Standard deviation of thorax acceleration, reflecting the variability of movement amplitude (body sway), was compared across groups over time in a 2 × 2 ANOVA design. Higuchi’s fractal dimension (HFD), reflecting the complexity of movement pattern over time, was also analyzed. Salivary cortisol and α-amylase samples were collected before and after the experiment, as stress biomarkers. Pearson’s correlation coefficients were calculated between these biomarkers and movement parameters.A significant interaction effect was found, showing that healthy controls reduced their thorax sway over time during exposure to stress (from 0.027 ± 0.010 m/s2 to 0.023 ± 0.008 m/s2, effect size of Cohen’s d = 0.95), whereas patients with FMD did not. This change in body sway in controls over time negatively correlated with salivary cortisol values (ρ = –0.67, p = 0.012). A significant group effect revealed that FMD patients had an overall larger body sway (0.038 ± 0.013 m/s2) compared to controls (0.025 ± 0.009 m/s2 – effect size of Cohen’s d = 1.29) and a lower HFD (1.602 ± 0.071) than controls (1.710 ± 0.078 – Cohen’s d = 1.43).Patients with FMD failed to show a reduction of body sway over time, i.e., freeze response observed in the controls, thus suggesting an impairment in the automatic defense behavior. Moreover, our analysis found a lower complexity of movement (HFD) in FMD, which deserves future research in order to verify whether this could represent a characteristic trait of the disorder.

Psychogenic movement disorders in children and adolescents: an update.

This short communication provides an update on childhood psychogenic movement disorders (PMD), focusing on descriptive studies and case reports from 2008 to 2018. Known also as functional movement/motor disorders, PMD diagnoses are relatively common in adults but less so in children. In group studies over the past decade, sample prevalence of childhood PMD ranged from 2.8 to 23.1%, with a higher percentage of girls in most studies (consistent with adult PMD literature). Common types of PMD included tremor (32.4%), dystonia (29.5%), and myoclonus (24.3%). Precipitating events for PMD onset included H1N1 influenza vaccinations, family/child stressors, anxiety/depression in the child or parent, panic attacks, behavior disorders, injury or accident, sexual abuse of the child or family member, death of a close relative, parental discord, domestic violence, school-related problems, medical illness/surgery, sleep disturbance, and participation in competitive sport or dance. The most frequently mentioned treatments were cognitive behavioral therapy, psychotherapy, relaxation techniques, and physiotherapy.Conclusion: Although additional cases of childhood PMD have been published over the past decade, little new information has appeared. There is still no "diagnostic gold standard," making an accurate estimate of prevalence virtually impossible and contributing to confusion among pediatricians when trying to identify children with PMD. What is Known: • Psychogenic movement disorders (PMD) occur in children as well as adults. • The most common types of childhood PMD are tremor, dystonia, and myoclonus. What is New: • The most common childhood PMD treatments were cognitive behavioral therapy, psychotherapy, physiotherapy, and relaxation techniques (2008-2018). • Due to lack of a standardized definition for PMD, confusion exists as to which movement disorders to include. With the inability to reliably diagnose PMD and the ambiguity as to which movement disorders it comprises, it is difficult to determine the most effective treatments.

Spinal Segmental Myoclonus Masquerading as a Psychogenic Movement Disorder

Spinal generated movement disorders are uncommon. An elderly gentleman presented with distressing jerks of both lower limbs which caused him much social embarrassment. He had received psychiatric treatment for these abnormal muscular spasms without relief. He had become depressed and withdrawn when he first presented to our outpatient department. A routine clinical examination followed by a long-term video EEG with simultaneous EMG clinched the diagnosis of a spinal segmental myoclonus. He underwent spinal decompression surgery with fixation followed by treatment with levetericetam and clonazepam which relieved his symptoms. Spinal generated movement disorders are uncommon and are often attributed to a psychiatric disorder in the absence of a better explanation. We take this opportunity to elaborate on the case details, investigations and the treatment of spinal myoclonus.

Abnormal postural behavior in patients with functional movement disorders during exposure to stress

BackgroundPatients affected by functional (psychogenic) movement disorders (FMD) have abnormal processing of stress responses. However, little is known about the influence of this abnormal stress processing on automatic motor defense behavior, such as freeze response. Our aim was thus to investigate stress-induced postural motor responses in FMD. MethodsNine FMD patients and thirteen healthy controls were engaged in the Trier Social Stress Test, while we measured the movement of their body by means of accelerometers and gyroscopes attached to the thorax. Standard deviation of thorax acceleration, reflecting the variability of movement amplitude (body sway), was compared across groups over time in a 2 × 2 ANOVA design. Higuchi’s fractal dimension (HFD), reflecting the complexity of movement pattern over time, was also analyzed. Salivary cortisol and α-amylase samples were collected before and after the experiment, as stress biomarkers. Pearson’s correlation coefficients were calculated between these biomarkers and movement parameters. ResultsA significant interaction effect was found, showing that healthy controls reduced their thorax sway over time during exposure to stress (from 0.027 ± 0.010 m/s2 to 0.023 ± 0.008 m/s2, effect size of Cohen’s d = 0.95), whereas patients with FMD did not. This change in body sway in controls over time negatively correlated with salivary cortisol values (ρ = –0.67, p = 0.012). A significant group effect revealed that FMD patients had an overall larger body sway (0.038 ± 0.013 m/s2) compared to controls (0.025 ± 0.009 m/s2 – effect size of Cohen’s d = 1.29) and a lower HFD (1.602 ± 0.071) than controls (1.710 ± 0.078 – Cohen’s d = 1.43). ConclusionsPatients with FMD failed to show a reduction of body sway over time, i.e., freeze response observed in the controls, thus suggesting an impairment in the automatic defense behavior. Moreover, our analysis found a lower complexity of movement (HFD) in FMD, which deserves future research in order to verify whether this could represent a characteristic trait of the disorder.

Response inhibition in patients with functional neurological symptom disorder

Abnormal response inhibition has been demonstrated in psychogenic movement disorders (PMD) and is a plausible mechanism for other forms of functional neurological symptom disorder (FNSD), in which response inhibition has not yet been investigated. Response inhibition was therefore studied in patients with FNSD, including patients with psychogenic non-epileptic seizures (PNES), functional weakness (FW) or both. Twenty-nine patients with FNSD and 29 age and sex-matched healthy volunteers underwent a go-nogo task, a stop-signal reaction time (SSRT) task, and a negative priming flanker task. The Attentional Resource Allocation Scale, the Beck Depression Inventory and the Spielberger State and Trait Anxiety Inventory were also administered. Mean hit rates on nogo trials, miss rates on go signals and discriminability index were higher and go signal reaction times were significantly longer in the FNSD group than in healthy controls. The presence of FW was associated with increased hit rates on nogo trials, suggesting a bias toward responding to nogo signals rather than missed go signals. SSRT and negative priming were not significantly different from healthy controls. It is unclear whether impaired performance on the go-nogo task reflects dysfunctional inhibitory processes, disordered attention, or impaired ability to discriminate between stimuli.

Motor Retraining (MoRe) for Functional Movement Disorders: Outcomes From a 1-Week Multidisciplinary Rehabilitation Program

BackgroundFunctional movement disorders (FMDs) are conditions of abnormal motor control thought to be caused by psychological factors. These disorders are commonly seen in neurologic practice, and prognosis is often poor. No consensus treatment guidelines have been established; however, the role of physical therapy in addition to psychotherapy has increasingly been recognized. This study reports patient outcomes from a multidisciplinary FMD treatment program using motor retraining (MoRe) strategies. ObjectiveTo assess outcomes of FMD patients undergoing a multidisciplinary treatment program and determine factors predictive of treatment success. DesignRetrospective chart review. SettingUniversity-affiliated rehabilitation institute. PatientsThirty-two consecutive FMD patients admitted to the MoRe program from July 2014–July 2016. InterventionPatients participated in a 1-week, multidisciplinary inpatient treatment program with daily physical, occupational, speech therapy, and psychotherapy interventions. Main Outcome MeasurementsPrimary outcome measures were changes in the patient-rated Clinical Global Impression Scale (CGI) and the physician-rated Psychogenic Movement Disorder Rating Scale (PMDRS) based on review of standardized patient videos. Measurements were taken as part of the clinical evaluation of the program. ResultsTwenty-four of the 32 patients were female with a mean age of 49.1 (±14.2) years and mean symptom duration of 7.4 (±10.8) years. Most common movement phenomenologies were abnormal gait (31.2%), hyperkinetic movements (31.2%), and dystonia (31.2%). At discharge, 86.7% of patients reported symptom improvement on the CGI, and self-reported improvement was maintained in 69.2% at the 6-month follow-up. PMDRS scores improved by 59.1% from baseline to discharge. Longer duration of symptoms, history of abuse, and comorbid psychiatric disorders were not significant predictors of treatment outcomes. ConclusionsThe majority of FMD patients experienced improvement from a 1-week multidisciplinary inpatient rehabilitation program. Treatment outcomes were not negatively correlated with longer disease duration or psychiatric comorbidities. The results from our study are encouraging, although further long-term prospective randomized studies are needed. Level of EvidenceIII

Oromandibular dystonia screening questionnaire for differential diagnosis.

Oromandibular dystonia, which is characterized by stereotypic, task-specific, or sustained contractions of masticatory and/or lingual muscles, is frequently misdiagnosed as temporomandibular disorders or psychogenic disease. Diagnostic delay in oromandibular dystonia is not acceptable; thus, a screening tool that can distinguish this condition from a temporomandibular disorder may be helpful for medical professionals unfamiliar with involuntary movements or temporomandibular disorders. A questionnaire that included questions on the clinical features of oromandibular dystonia, such as stereotypy, task-specificity, sensory tricks, and morning benefit, and included questions to rule out temporomandibular disorders (total point range 0-40) was administered to 553 patients suspected to have involuntary movements. Based on a careful examination and the differential diagnosis, the patients were divided into four groups: oromandibular dystonia (n= 385), oral dyskinesia (n= 84), psychogenic (functional) movement disorder (n= 50), and temporomandibular disorders (n= 34). The questionnaire had a high level of internal consistency as measured by the Cronbach's α (0.91), and item-total correlation was significant (p < 0.001). The test-retest reliability on two separate occasions showed a significant correlation (p < 0.001). Mean total scores of the questionnaire significantly differed among oromandibular dystonia (32.0), temporomandibular disorders (10.4; one-way analysis of variance, p < 0.001), oral dyskinesia (21.0; p < 0.001), and psychogenic (functional) movement disorder (13.7; p < 0.001). Findings of this study suggest that the present questionnaire is a simple diagnostic tool that is useful for tentative differentiation of oromandibular dystonia from temporomandibular disorders. This screening tool can be used to distinguish oromandibular dystonia from temporomandibular disorders.

Acute hyperkinetic movement disorders in Italian paediatric emergency departments

IntroductionLimited data exist on epidemiology, clinical presentation and management of acute hyperkinetic movement disorders (AHMD) in paediatric emergency departments (pED).MethodsWe retrospectively analysed a case series of 256 children (aged 2...

Neuroimaging Applications in Functional Movement Disorders.

Functional (psychogenic) movement disorders are a subtype of functional neurological disorder, a common and disabling cause of neurological symptoms. Abnormal movement in people with functional movement disorders has specific characteristics (e.g., distractibility, variability, incongruence with deficits caused by neurological disease), allowing positive diagnosis and differentiation from other causes of movement disorder. Attempts to understand the pathophysiology of this disorder have previously focused mainly on the psychological level, emphasizing the importance of psychological trauma and adverse life events. However, the last two decades has seen a broadening of this approach to consider the neurobiological level, and brain imaging has formed a key part of this work. Here we review the available imaging evidence in functional movement disorders and explain how this evidence can help us understand more about the underlying pathophysiology of this common cause of abnormal movement control.

Impaired freeze response in psychogenic (functional) movement disorder patients during exposure to stress

Objective: The freeze response, a reduced body motion as reaction to threats, is typically observed in healthy humans exposed to stress. Patients affected by psychogenic (functional) movement disorders (PMD) have abnormal processing of stress, and present hyper-activity in the hypothalamic-pituitary-adre- nal-axis stress system (elevated cortisol levels).

Motor Symptoms of Autoimmune Encephalopathies

Autoimmune encephalopathies are clinically and immunologically heterogeneous disorders. At least 20 types of autoimmune encephalopathies have been discovered, with the most common type being Hashimoto encephalopathy. In clinical situations, we often observe that patients with autoimmune encephalopathy are misdiagnosed because they exhibit signs similar to those observed in functional psychogenic movement, conversion, or somatoform disorders. We clinically examined over 100 patients with autoimmune encephalopathy. These patients primarily demonstrated motor disturbances, mostly with give-way weakness, sensory abnormalities, and involuntary movements such as tremor entrainment, dystonia, or coarse involuntary movement. In addition, we observed memory loss, psychogenic non-epileptic seizures, epilepsy, and autonomic symptoms in our patients. To diagnose autoimmune encephalopathies, we propose that a combination of neurological symptoms indicating "diffuse brain damage" be used. "Diffuse brain damage" is a proof of several symptoms, such as give-way weakness; motor symptoms such as paralysis, smoothness disorder of exercise, involuntary movements, and difficulty to sustain; abnormal sensations such as pain, abnormal perception of various parts, and impaired vibration sensation; deterioration of higher order functions such as memory and learning ability; and impairment of the visual processing system and various visual abnormalities. As patients with autoimmune encephalitis exhibit diffuse involvement, the presence of these symptoms was entirely understandable. Over three such abnormal findings could indicate diffuse brain damage. Owing to the regular understanding in neurology, most patients tend to be diagnosed with somatoform disorders. Thus, physicians should not diagnose somatoform disorders without first excluding autoimmune encephalopathy.

Psychogenic movement disorders

Psychogenic (or functional) movement disorders are movement disorders of presumed psychiatric etiology. We think of the symptoms, in Freudian terms, as arising from a conversion of the psychiatric symptoms into somatic ones. The psychiatric factors are likely important, and dealing with them can be a route to improvement, but understanding the patient may require a full biopsychosocial model of disease. Patients often have psychiatric co-morbidities, such as anxiety and depression, early life and contemporaneous stress. Women are affected more than men, and patients are seen at all ages. Some patients have factitious disorder or malingering, but these patients are rare, and we cannot easily separate them from the large majority with somatization. In terms of quality of life, patients with a functional movement disorder are worse than those with Parkinson’s disease. Common manifestations are tremor, myoclonus, dystonia, and gait disorders. There are clinical clues that can help make the diagnosis, and there are clinical neurophysiological studies that are particularly helpful for tremor and myoclonus. Neuroimaging research in psychogenic movement disorders has begun to shed some light on the underlying biology, and there is some evidence for abnormal function of the amygdala which might be able to trigger involuntary movements. Only neurologists can make the diagnosis of these patients. Psychiatrists are not trained to do this, but must help with patient management. Treatment has been problematic and needs to be multidisciplinary, including pharmacotherapy, psychotherapy, social work, and physical therapy.

P 79 Physiological assessment of the sense of agency in psychogenic movement disorders

Psychogenic movement disorders (PMD) are conditions characterized by the occurrence of unwanted motoric symptoms in which a somatic reason cannot be found. As patients suffering from PMD experience their pathological movements as non-voluntary, it is hypothesized that those patients have an altered sense of agency (SoA). SoA is defined as the feeling of controlling ones own actions and through them controlling events in the external world ( Haggard and Tsakiris, 2009 ). SoA can be assessed by measuring the intentional binding (IB) effect. This is the perceived convergence of the time between a voluntary action and an auditory stimulus provoked by that action. To test the hypothesis we used a setting based on the Libet clock method ( Libet et al., 1983 ) introduced by Haggard et al. (2002) . To date, in total 59 subjects were enrolled: 5 subjects with the diagnosis of PMD, 35 with a somatic movement disorder (SMD) and 19 healthy controls. SMD patient group consisted of patients with Parkinsons disease ( n = 18), neuropathies ( n = 10), stroke ( n = 7) and multiple sclerosis ( n = 1). IB values were 0.18 ± 0.06 s for PMD, 0.16 ± 0.09 s for SMD and 0.12 ± 0.09 s for healthy controls (mean ± SD). So far, there were no significant differences in IB between PMD, SMD and healthy controls in the examined study group (PMD vs. healthy controls, p = 0.1. Two-sample t -tests). Patients with a motor disorder (both SMD and PMD) tended to have higher IB values compared to healthy controls (SMD vs. healthy controls, p = 0.08). IB values did not differ between SMD and PMD patients (PMD vs. SMD, p = 0.7). Our findings are in line with evidence derived from small study groups that binding processes are altered in PMD patients compared to healthy controls ( Kranick et al., 2013 ). However, since PMD patients did not differ from SMD patients, a specific binding problem is unlikely to represent the pathophysiological mechanism in psychogenic movement disorders.