Motor functional neurological disorders: An update

'Positive' inter-ictal clinical signs of functional neurological disorders are found in patients with functional dissociative seizures

BACKGROUND AND PURPOSE

Prior studies highlighted the high diagnostic specificity (ranging from 92% to 100%) of clinical signs observed in functional neurological disorders (FNDs). However, these signs are rarely looked for by epileptologists when trying to distinguish between functional dissociative seizure (FDS) and epileptic seizure. The aim of this study was to determine the prevalence of inter-ictal clinical signs of FND in a cohort of patients with probable FDS. The secondary objective was to compare the prevalence of inter-ictal FND clinical signs in FDS patients with age- and gender-matched epileptic patients without FDS.

METHODS

Patients diagnosed with FDS seen at two tertiary care centres and epileptic outpatients were included in the study. Each patient underwent a physical examination, searching for inter-ictal clinical signs of FND.

RESULTS

In the FDS group, 79% of patients presented at least one sign of FND, compared to 16.6% of patients with epilepsy (p < 0.001). Moreover, 66.6% of FDS patients presented three or more FND signs, whereas only 4.1% of epileptic patients did (p < 0.001). The median number of FND clinical signs in the FDS group was four (SD 1.7; 5.5). Using the threshold of three signs or more, the specificity of detecting three or more FND signs was 83.3%, with a sensitivity of 79.2%.

CONCLUSION

Inter-ictal clinical signs of FND are present in patients with FDS and should be looked for during neurological examination.

A global neuronal workspace model of functional neurological disorders

We introduce here a general model of Functional Neurological Disorders based on the following hypothesis: a Functional Neurological Disorder could correspond to a consciously initiated voluntary top-down process causing involuntary lasting consequences that are consciously experienced and subjectively interpreted by the patient as involuntary. We develop this central hypothesis according to Global Neuronal Workspace theory of consciousness, that is particularly suited to describe interactions between conscious and non-conscious cognitive processes. We then present a list of predictions defining a research program aimed at empirically testing their validity. Finally, this general model leads us to reinterpret the long-debated links between hypnotic suggestion and functional neurological disorders. Driven by both scientific and therapeutic goals, this theoretical paper aims at bringing closer the psychiatric and neurological worlds of functional neurological disorders with the latest developments of cognitive neuroscience of consciousness.

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.

Use of non-invasive neurostimulation for rehabilitation in functional movement disorders

Functional movement disorders (FMD) are a subtype of functional neurological disorders which involve abnormal movements and include multiple phenomenologies. There is a growing interest in the mechanism, diagnosis, and treatment of these disorders. Most of the current therapeutic approaches rely on psychotherapy and physiotherapy conducted by a multidisciplinary team. Although this approach has shown good results in some cases, FMD cause a great burden on the health system and other treatment strategies are urgently needed. In this review, we summarize past studies that have applied non-invasive neurostimulation techniques, such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and peripheral nerve stimulation as a treatment for FMD. There is an increasing number of studies related to TMS including randomized controlled trials; however, the protocols amongst studies are not standardized. There is only preliminary evidence for the efficacy of non-invasive neuromodulation in reducing FMD symptoms, and further studies are needed. There is insufficient evidence to allow implementation of these techniques in clinical practice.

Compassion-Focused Therapy for an Older Adult with Motor Functional Neurological Disorder: A Case Study

OBJECTIVES

Motor functional neurological disorder (mFND) is a condition where individuals may experience difficulties such as tremors, gait impairments, and paralysis which are not explained by identified structural damage to the brain. Studies on chronic conditions have suggested that psychological interventions such as compassion-focused therapy (CFT) may be effective in improving well-being in people with mFND. However, no evidence is currently available on psychotherapy for older people with mFND.

METHODS

A 12-session CFT intervention was delivered to an 81-year-old British male with mFND. Standardized measures were administered at baseline and post-intervention.

RESULTS

At post-intervention, a 30% decrease in perceived psychological impact of mFND was found, along with clinically significant changes in anxiety and depression. Good levels of feasibility and acceptability were also observed.

CONCLUSIONS

To our knowledge, this is the first evidence of the feasibility, acceptability, and potential effectiveness of CFT for psychological difficulties linked with mFND, as well as the first evidence for any psychotherapy with an older adult with mFND.

CLINICAL IMPLICATIONS

CFT shows the potential to be effective, feasible, and acceptable for treating difficulties linked with mFND in older people. However, further high-quality investigations based on experimental designs are needed to build on the present preliminary findings.

Is hypnotic assessment relevant to neurology?

Studies conducted in healthy subjects have clearly shown that different hypnotic susceptibility, which is measured by scales, is associated with different functional equivalence between imagery and perception/action (FE), cortical excitability, and information processing. Of note, physiological differences among individuals with high (highs), medium (mediums), and low hypnotizability scores (lows) have been observed in the ordinary state of consciousness, thus independently from the induction of the hypnotic state, and in the absence of specific suggestions. The potential role of hypnotic assessment and its relevance to neurological diseases have not been fully explored. While current knowledge and therapies allow a better survival rate, there is a constant need to optimize rehabilitation treatments and quality of life. The aim of this paper is to provide an overview of hypnotizability-related features and, specifically, to discuss the hypothesis that the stronger FE, the different mode of information processing, and the greater proneness to control pain and the activity of the immune system observed in individuals with medium-to-high hypnotizability scores have potential applications to neurology. Current evidence of the outcome of treatments based on hypnotic induction and suggestions administration is not consistent, mainly owing to the small sample size in clinical trials and inadequate control groups. We propose that hypnotic assessment may be feasible in clinical routine and give additional cues into the treatment and rehabilitation of neurological diseases.

Psychological interventions for treating functional motor symptoms: A systematic scoping review of the literature

Functional Movement Disorders (FMD) can be identified by limb weakness, gait disorders, or involuntary movements which are inconsistent with a neurological diagnosis. Despite the prevalence of such symptoms, there has been little consensus on models for treatment. This scoping review set out to identify the literature exploring the efficacy of psychological interventions for the treatment of FMD, either as a stand-alone intervention or as part of a multi-disciplinary team approach. Studies set in an adult inpatient and outpatient setting were considered for inclusion. The final review consisted of 33 papers; 13 reviewing psychological treatments only, and 20 reviewing multidisciplinary approaches that included a psychological intervention. This review of the literature reaffirms the inconsistency across treatment for FMD, although identifies a trend towards an MDT approach in recent years. The review also identifies areas where consistency in methodology may be beneficial in future research, in order to improve the validity of results for greater comparison of treatments. There are promising outcomes that support the continued investigation focused on an interdisciplinary, collaborative approach to care, for the reduction of symptoms.

Clinical and demographic characteristics of patients with functional movement disorders: a consecutive cohort study from a specialized clinic

There is a growing interest in functional movement disorders (FMD). However, epidemiological data from large cohorts of patients with FMD are scarce and come mainly from General Neurology and Movement Disorders Clinics. Recently, specialized FMD clinics have been developed and epidemiological data from such clinics may provide useful information. We aimed to describe the clinical and sociodemographic features of patients diagnosed with FMD at our specialized FMD clinic. A standardized form was used to extract data from electronic records from the first-100 consecutive patients who were evaluated and diagnosed with FMD at our clinic from 2017 to 2019. Mean age was 40.88 ± (14.02) years, 63% females. Most patients were within working-age range, but only 16% were working at the time of consultation. Mean disease duration was 3.74 ± 5.73 years and was longer among men. The most common FMD were gait disturbance (42%), tremor (22%) and dystonia (15%). A precipitating event (mainly physical) was reported by 74%. The onset was mostly acute (83%) and the clinical course fluctuating (62%). Pain (64%) and fatigue (44%) were common comorbidities. Potential joint-hypermobility was present in 21%, mostly women (90%) and related to the presence of dystonia. FMD affects men and women mostly in working-age. Gait disturbance was the most common diagnosis, possibly because it causes a higher level of disability that may lead to consultation in a specialized clinic. Non-motor symptoms (pain and fatigue) were frequent in this cohort. Further data from specialized units may contribute to both understanding and management of FMD.

Functional MRI-based study of emotional experience in patients with psychogenic non-epileptic seizures: Protocol for an observational case-control study–EMOCRISES study

Background

Psychogenic non epileptic seizures (PNES) are a frequent, disabling and costly disorder for which there is no consensual caring. They are considered as a dissociative disorder and they share many common characteristics with post-traumatic stress disorder (PTSD). Nevertheless, their pathophysiology is still unclear. In this study, we plan to obtain new data comparing functional brain activity of participants suffering from PNES, from PTSD and healthy controls via functional brain MRI during resting state and under emotional visual stimulation. The protocol presented hereunder describes an observational study with no direct treatment implication. Nevertheless, it could lead to a better understanding of PNES and to identifying targets for specialised cares of post-traumatic or dissociative disorders, like repetitive transcranial magnetic stimulation.

Methods & analysis

This is a prospective, single-centre, interventional, non-randomized, open, controlled and exploratory clinical study. It will involve 75 adult French, right-handed women in 3 groups, either suffering from PNES or PTSD, or healthy controls. An informed consent will be signed by each participant. All of them will be given psychiatric tests to assess dissociation and alexithymia, psychopathological profile and history, and emotional recognition. Each participant will undergo a functional brain MRI. We will record anatomical images and five functional imaging sequences including emotional periodic oscillatory stimulation, standard emotional stimulation, Go / No Go task under emotional stimulation, and resting state. Analysis will include a descriptive analysis of all participants and the treatment for functional magnetic resonance imaging images of each sequence.

Registration, ethics & dissemination

This study was approved the regional Protection of Persons Committee under the reference 16.10.01 and by the French National Medical Security Agency under the reference 2016-A01295-46. The protocol and results will be published in peer-reviewed academic medical journals and disseminated to research teams, databases, specialised media and concerned patients’ organisations.

Neurostimulation for the treatment of functional neurological disorder: A systematic review

Functional Neurological Disorder (FND), also known as conversion disorder, is characterized by neurological symptoms that are incompatible with any known structural disorder and best explained by a biopsychosocial model. Evidence-based treatments for FND are limited, with cognitive behavioral therapy (CBT) and physiotherapy being the most effective interventions [1]. In recent years, functional neuroimaging studies have provided robust evidence of alterations in activity and connectivity in multiple brain networks in FND. This body of evidence suggests that neurocircuitry-based interventions, such as non-invasive brain stimulation techniques (NIBS), may also represent an effective therapeutic option for patients with FND. In this systematic review, we outline the current state of knowledge of NIBS in FND, and discuss limitations and future directions that may help establish the efficacy of NIBS as a therapeutic option for FND.

Implicit motor imagery using laterality recognition in functional movement disorders

Functional movement disorder (FMD) presents as disabling motor symptoms that cannot be explained by organic processes. Despite the lack of lesion or known central nervous system dysfunction, distortion in sensorimotor processing in movement generation and execution is often observed. A person's capacity to judge laterality of a body part requires processing of sensorimotor information. This prospective observational study compared reaction time (RT) and accuracy (ACC) of hand laterality recognition between 30 people diagnosed with FMD and 30 age-matched healthy control participants. The association of RT and ACC with severity of FMD as measured by the Simplified Functional Movement Disorders Rating Scale (SFMDRS) was also explored. RT was on average 0.6 s slower (95% CI 0.4 - 0.8 s, p < 0.001) in patients with FMD (mean 2.2 s, standard deviation (SD) 0.5) than controls (mean 1.7 s, SD 0.3). ACC was on average 8.9% lower (95% CI -15.7 - -2.2, p = 0.01) in patients with FMD (mean 79.6%, SD 16.6) than controls (mean 88.5%, SD 8.1). When adjusted for SFMDRS using robust regression, RT was 0.3 s slower (95% CI 0.01 - 0.5, p = 0.04) in cases than in controls, but ACC was no longer different between groups. There was a moderate negative correlation between RT and ACC in FMD patients (ρ -0.58, p < 0.001 but not in controls (ρ -0.26, p = 0.17). People with FMD had significantly slower RT and lower ACC compared to the control group. These results provide new insights into underlying sensorimotor processing deficits in those with FMD.

The neuroimaging evidence of brain abnormalities in functional movement disorders

Neuroimaging has been pivotal in identifying and reframing our understanding of functional movement disorders (FMDs). If accessible, it compensates for the limitations of the clinical exam and is especially useful where there is overlap of functional symptoms with classical presentations of disease. Imaging in FMDs has increasingly identified structural and functional abnormalities that implicate hypoactivation of the cortical and subcortical motor pathways and increased modulation by the limbic system. Neurobiological theories suggest an impaired sense of agency, faulty top-down regulation of motor movement and abnormal emotional processing in these individuals. This framework challenges our traditional understanding of FMDs as distinct from the deceptive term of 'organic' diseases and proposes that these conditions not be considered as mutually exclusive. This review summarizes the literature to date and explores the role of imaging in the diagnosis of FMDs and in detecting its underlying molecular network.

Psychosocial interventions for conversion and dissociative disorders in adults

BACKGROUND

Conversion and dissociative disorders are conditions where people experience unusual neurological symptoms or changes in awareness or identity. However, symptoms and clinical signs cannot be explained by a neurological disease or other medical condition. Instead, a psychological stressor or trauma is often present. The symptoms are real and can cause significant distress or problems with functioning in everyday life for the people experiencing them.

OBJECTIVES

To assess the beneficial and harmful effects of psychosocial interventions of conversion and dissociative disorders in adults.

SEARCH METHODS

We conducted database searches between 16 July and 16 August 2019. We searched Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and eight other databases, together with reference checking, citation searching and contact with study authors to identify additional studies.  SELECTION CRITERIA: We included all randomised controlled trials that compared psychosocial interventions for conversion and dissociative disorders with standard care, wait list or other interventions (pharmaceutical, somatic or psychosocial).  DATA COLLECTION AND ANALYSIS: We selected, quality assessed and extracted data from the identified studies. Two review authors independently performed all tasks. We used standard Cochrane methodology. For continuous data, we calculated mean differences (MD) and standardised mean differences (SMD) with 95% confidence interval (CI). For dichotomous outcomes, we calculated risk ratio (RR) with 95% CI. We assessed and downgraded the evidence according to the GRADE system for risk of bias, imprecision, indirectness, inconsistency and publication bias.

MAIN RESULTS

We included 17 studies (16 with parallel-group designs and one with a cross-over design), with 894 participants aged 18 to 80 years (female:male ratio 3:1).  The data were separated into 12 comparisons based on the different interventions and comparators. Studies were pooled into the same comparison when identical interventions and comparisons were evaluated. The certainty of the evidence was downgraded as a consequence of potential risk of bias, as many of the studies had unclear or inadequate allocation concealment. Further downgrading was performed due to imprecision, few participants and inconsistency. There were 12 comparisons for the primary outcome of reduction in physical signs. Inpatient paradoxical intention therapy compared with outpatient diazepam: inpatient paradoxical intention therapy did not reduce conversive symptoms compared with outpatient diazepam at the end of treatment (RR 1.44, 95% CI 0.91 to 2.28; 1 study, 30 participants; P = 0.12; very low-quality evidence). Inpatient treatment programme plus hypnosis compared with inpatient treatment programme: inpatient treatment programme plus hypnosis did not reduce severity of impairment compared with inpatient treatment programme at the end of treatment (MD -0.49 (negative value better), 95% CI -1.28 to 0.30; 1 study, 45 participants; P = 0.23; very low-quality evidence). Outpatient hypnosis compared with wait list: outpatient hypnosis might reduce severity of impairment compared with wait list at the end of treatment (MD 2.10 (higher value better), 95% CI 1.34 to 2.86; 1 study, 49 participants; P < 0.00001; low-quality evidence). Behavioural therapy plus routine clinical care compared with routine clinical care: behavioural therapy plus routine clinical care might reduce the number of weekly seizures compared with routine clinical care alone at the end of treatment (MD -21.40 (negative value better), 95% CI -27.88 to -14.92; 1 study, 18 participants; P < 0.00001; very low-quality evidence). Cognitive behavioural therapy (CBT) compared with standard medical care: CBT did not reduce monthly seizure frequency compared to standard medical care at end of treatment (RR 1.56, 95% CI 0.39 to 6.19; 1 study, 16 participants; P = 0.53; very low-quality evidence). CBT did not reduce physical signs compared to standard medical care at the end of treatment (MD -4.75 (negative value better), 95% CI -18.73 to 9.23; 1 study, 61 participants; P = 0.51; low-quality evidence). CBT did not reduce seizure freedom compared to standard medical care at end of treatment (RR 2.33, 95% CI 0.30 to 17.88; 1 trial, 16 participants; P = 0.41; very low-quality evidence). Psychoeducational follow-up programmes compared with treatment as usual (TAU): no study measured reduction in physical signs at end of treatment. Specialised CBT-based physiotherapy inpatient programme compared with wait list: no study measured reduction in physical signs at end of treatment. Specialised CBT-based physiotherapy outpatient intervention compared with TAU: no study measured reduction in physical signs at end of treatment. Brief psychotherapeutic intervention (psychodynamic interpersonal treatment approach) compared with standard care: brief psychotherapeutic interventions did not reduce conversion symptoms compared to standard care at end of treatment (RR 0.12, 95% CI 0.01 to 2.00; 1 study, 19 participants; P = 0.14; very low-quality evidence). CBT plus adjunctive physical activity (APA) compared with CBT alone: CBT plus APA did not reduce overall physical impacts compared to CBT alone at end of treatment (MD 5.60 (negative value better), 95% CI -15.48 to 26.68; 1 study, 21 participants; P = 0.60; very low-quality evidence). Hypnosis compared to diazepam: hypnosis did not reduce symptoms compared to diazepam at end of treatment (RR 0.69, 95% CI 0.39 to 1.24; 1 study, 40 participants; P = 0.22; very low-quality evidence). Outpatient motivational interviewing (MI) and mindfulness-based psychotherapy compared with psychotherapy alone: psychotherapy preceded by MI might decrease seizure frequency compared with psychotherapy alone at end of treatment (MD 41.40 (negative value better), 95% CI 4.92 to 77.88; 1 study, 54 participants; P = 0.03; very low-quality evidence). The effect on the secondary outcomes was reported in 16/17  studies. None of the studies reported results on adverse effects. In the studies reporting on level of functioning and quality of life at end of treatment the effects ranged from small to no effect.

AUTHORS' CONCLUSIONS

The results of the meta-analysis and reporting of single studies suggest there is lack of evidence regarding the effects of any psychosocial intervention on conversion and dissociative disorders in adults. It is not possible to draw any conclusions about potential benefits or harms from the included studies.

Functional neurological disorders: effective teaching for health professionals

Objectives

To provide an outline for the delivery of an educational course or lecture about functional neurological disorders (FND) that is directed towards health professionals with varying clinical knowledge and to highlight the educational efficacy that can be derived from a well-designed educational platform.

Method

Through multidisciplinary collaboration, a course designed to develop the skills for diagnosis and management of FND was created. Elements essential to the delivery of education are: (A) knowledge creation; (B) facilitating multidisciplinary cross-pollination; (C) listening to patients’ experiences; (D) communication skills practice; (E) case studies; (F) discipline specific mentoring; (G) establishing and addressing participant learning goals and (H) developing collegial and referral networks. Changes in participants’ knowledge and clinical practice were assessed via anonymous questionnaires before and after the course.

Results

Dramatically improved knowledge and confidence in assessment and management of people with FND has been found both immediately following the course as well as on 6-month follow-up.

Conclusion

It is possible to make real change in the understanding and management of medical and allied health clinicians working with people with FND with a low-cost intervention. Also, the development of educational networks and multidisciplinary collaboration can lead to the creation of therapeutic platforms for the diagnosis, management and advocacy of this patient group.

Maximizing placebo response in neurological clinical practice

The placebo effect is a widely recognized phenomenon in clinical research, with a negative perception that it could hide the "true" drug effect. In clinical care its positive potential to increase known drug effects has been neglected for too long. The placebo and nocebo responses have been described in many neurologic disorders such as Parkinson's, Huntington's and Alzheimer's diseases, restless leg syndrome, tics, essential tremor, dystonia, functional movement disorders, neuropathic pain, headaches, migraine, amyotrophic lateral sclerosis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, multiple sclerosis and epilepsy. Knowledge regarding placebo mechanisms and their consequences on clinical outcome have greatly improved over the last two decades. This evolution has led to reconsiderations of the importance of placebo response in the clinic and has given several clues on how to improve it in daily practice. In this chapter, we first illustrate "why," e.g. the reasons (relevance to clinical practice, help in differential diagnosis/treatment of psychogenic movements, clinical impact, proven neurobiological grounds, health economic potential), and "how," e.g. the means (increase patients' knowledge, increase learning, improve patient-doctor relationship, increase Hawthorne effect, increase positive/decrease negative expectations (the Rosenthal effect), personalize placebo response), the placebo should be maximized (and nocebo avoided) in neurological clinical practice. Future studies regarding more specific neurobiological mechanisms will allow a finer tuning of placebo response in clinical practice. The use of placebo in clinical practice raises ethical issues, and a recent expert consensus regarding placebo use in the clinic is a first step to future guidelines necessary to this field.

Physical therapy modalities in neurological disorders at developmental age - Assessment of the methodological value of research papers

BACKGROUND

Physical therapy modalities are often applied in treatment of neurological conditions in children and adolescents.

OBJECTIVE

Evaluation of the methodological quality of research focusing on the application of physical therapy modalities in children and adolescents with neurological conditions.

METHODS

Papers published between 2007 and 2018 were included in the review. 149 papers were analyzed and finally 26 studies investigating the use of physical therapy modalities in children and adolescents with neurological conditions were included in the review. Jadad scale (0-5) was used to assess the methodological value of the studies.

RESULTS

The mean Jadad score was 1.46 (researcher 1) and 1.38 (researcher 2). A score of 0 was awarded to nine (r1) and eight papers (r2). A score of 5 points was awarded to three (r1) and two papers (r2).

CONCLUSION

1. The evidence showing the effectiveness of the use of physical therapy modalities is mainly of low quality. 2. The Jadad scale is a valuable tool to assess the quality of research, although it does not always reflect the real value in the case children participate in studies. 3. The analyzed studies show that physical therapy modalities are effective in the treatment of children and adolescents with neurological disorders.

Characteristics of patients with motor functional neurological disorder in a large UK mental health service: a case-control study

BACKGROUND

Functional neurological disorder (FND), previously known as conversion disorder, is common and often results in substantial distress and disability. Previous research lacks large sample sizes and clinical surveys are most commonly derived from neurological settings, limiting our understanding of the disorder and its associations in other contexts. We sought to address this by analysing a large anonymised electronic psychiatric health record dataset.

METHODS

Data were obtained from 322 patients in the South London and Maudsley NHS Foundation Trust (SLaM) who had an ICD-10 diagnosis of motor FND (mFND) (limb weakness or disorders of movement or gait) between 1 January 2006 and 31 December 2016. Data were collected on a range of socio-demographic and clinical factors and compared to 644 psychiatric control patients from the same register.

RESULTS

Weakness was the most commonly occurring functional symptom. mFND patients were more likely to be female, British, married, employed pre-morbidly, to have a carer and a physical health condition, but less likely to have had an inpatient psychiatric admission or to receive benefits. No differences in self-reported sexual or physical abuse rates were observed between groups, although mFND patients were more likely to experience life events linked to inter-personal difficulties.

CONCLUSIONS

mFND patients have distinct demographic characteristics compared with psychiatric controls. Experiences of abuse appear to be equally prevalent across psychiatric patient groups. This study establishes the socio-demographic and life experience profile of this understudied patient group and may be used to guide future therapeutic interventions designed specifically for mFND.

Invalidation of Parkinson's disease diagnosis after years of follow-up based on clinical, radiological and neurophysiological examination

INTRODUCTION

Diagnosis of Parkinson's disease (PD) is mainly based on clinical features. Accurate neurological examination is required but dopamine transporter (DaT) single photon emission computed tomography (SPECT) could be perfomed to support the diagnosis in ambiguous cases. The aim of this work is to describe the characteristics of patients with a prolonged PD misdiagnosis.

METHODS

We collected data from 24 patients initially diagnosed with PD who had an atypical long-term evolution. We analyzed demographic and clinical characteristics and antiparkinsonian drugs medication. Brain MRI, DaT-SPECT and/or accelerometry/electromyography (EMG) recording were performed in a subgroup of patients. We analyzed the causes of erroneous PD diagnosis as well as the final diagnoses.

RESULTS

Mean age at PD diagnosis was 60.4 ± 14.8 years. Symptoms at onset were rest tremor (n = 19), gait instability (n = 7) and micrographia (n = 4). Mean duration before diagnosis correction was 8.4 ± 5.3 years. All patients were treated by antiparkinsonian drugs with a mean daily levodopa equivalent dose (LED) of 508.1 ± 528.4 mg. All 18 patients who underwent DaT-SPECT had a normal result. The most frequent final diagnoses were essential tremor (n = 11) and functional movement disorders (n = 9).

CONCLUSION

Cases that have been initially diagnosed as PD and then progress in an atypical long-duration fashion may have been misdiagnosed. Absence of genuine bradykinesia, non-sustained response to antiparkinsonian drugs, or absence of levodopa-related side effects should prompt the clinician to reappraise the diagnosis and to consider performing a DaT-SPECT.