Outcome measurement in functional neurological disorder: a systematic review and recommendations.

OBJECTIVES: We aimed to identify existing outcome measures for functional neurological disorder (FND), to inform the development of recommendations and to guide future research on FND outcomes. METHODS: A systematic review was conducted to identify existing FND-specific outcome measures and the most common measurement domains and measures in previous treatment studies. Searches of Embase, MEDLINE and PsycINFO were conducted between January 1965 and June 2019. The findings were discussed during two international meetings of the FND-Core Outcome Measures group. RESULTS: Five FND-specific measures were identified-three clinician-rated and two patient-rated-but their measurement properties have not been rigorously evaluated. No single measure was identified for use across the range of FND symptoms in adults. Across randomised controlled trials (k=40) and observational treatment studies (k=40), outcome measures most often assessed core FND symptom change. Other domains measured commonly were additional physical and psychological symptoms, life impact (ie, quality of life, disability and general functioning) and health economics/cost-utility (eg, healthcare resource use and quality-adjusted life years). CONCLUSIONS: There are few well-validated FND-specific outcome measures. Thus, at present, we recommend that existing outcome measures, known to be reliable, valid and responsive in FND or closely related populations, are used to capture key outcome domains. Increased consistency in outcome measurement will facilitate comparison of treatment effects across FND symptom types and treatment modalities. Future work needs to more rigorously validate outcome measures used in this population

Functional neurological disorders in Parkinson disease

OBJECTIVE: To ascertain demographic and clinical features of Parkinson disease (PD) associated with functional neurological features. METHODS: A standardised form was used to extract data from electronic records of 53 PD patients with associated functional neurological disorders (PD-FND) across eight movement disorders centres in the USA, Canada and Europe. These subjects were matched for age, gender and disease duration to PD patients without functional features (PD-only). Logistic regression analysis was used to compare both groups after adjusting for clustering effect. RESULTS: Functional symptoms preceded or co-occurred with PD onset in 34% of cases, nearly always in the most affected body side. Compared with PD-only subjects, PD-FND were predominantly female (68%), had longer delay to PD diagnosis, greater prevalence of dyskinesia (42% vs 18%; P=0.023), worse depression and anxiety (P=0.033 and 0.025, respectively), higher levodopa-equivalent daily dose (972±701 vs 741±559 mg; P=0.029) and lower motor severity (P=0.019). These patients also exhibited greater healthcare resource utilisation, higher use of [(123)I]FP-CIT SPECT and were more likely to have had a pre-existing psychiatric disorder (P=0.008) and family history of PD (P=0.036). CONCLUSIONS: A subtype of PD with functional neurological features is familial in one-fourth of cases and associated with more psychiatric than motor disability and greater use of diagnostic and healthcare resources than those without functional features. Functional manifestations may be prodromal to PD in one-third of patients

Opinions and clinical practices related to diagnosing and managing functional (psychogenic) movement disorders: Changes in the last decade.

BACKGROUND: There is large variability in the diagnostic approach and clinical management in functional movement disorders (FMD). This study aimed to examine whether opinions and clinical practices related to FMD have changed over the past decade. METHODS: A survey to members of the International Parkinson and Movement Disorder Society (MDS). RESULTS: We received 864/7689 responses (denominator includes non-neurologists) from 92 countries. Respondents were more often male (55%), younger than 45 (65%), and from academic practices (85%). Although the likelihood of ordering neurological investigations prior to delivering a diagnosis of FMD was nearly as high as in 2008 (47% versus 51%), the percentage of respondents communicating the diagnosis without requesting additional tests increased (27% versus 19%; p=0.003), with most envisioning their role as providing a diagnosis and coordinating management (57% versus 40%; p<0.001). Compared to patients with other disorders, 64% of respondents were more concerned about missing a diagnosis of another neurological disorder. Avoiding iatrogenic harm (58%) and educating patients about the diagnosis (53%) were again rated as the most effective therapeutic options. Frequent treatment barriers included lack of physician knowledge and training (32%), lack of treatment guidelines (39%), limited availability of referral services (48%), and cultural beliefs about psychological illnesses (50%). The preferred term for communication favored "functional" over "psychogenic" (p<0.001). CONCLUSIONS: Attitudes and management of FMD have changed over the past decade. Important gaps remain in the education of neurologists about the inclusionary approach to FMD diagnosis, and improving access to treatment

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

Action-effect binding is decreased in motor conversion disorder: implications for sense of agency

The abnormal movements seen in motor conversion disorder are affected by distraction and entrainment, similar to voluntary movement. Unlike voluntary movement, however, patients lack a sense of control for the abnormal movements, a failure of “self‐agency.” The action‐effect binding paradigm has been used to quantify the sense of self‐agency, because subjective contraction of time between an action and its effect only occurs if the patient feels that they are the agent responsible for the action. We used this paradigm, coupled with emotional stimuli, to investigate the sense of agency with voluntary movements in patients with motor conversion disorder. Twenty patients with motor conversion disorder and 20 age‐matched and sex‐matched healthy volunteers used a rotating clock to judge the time of their own voluntary key presses (action) and a subsequent auditory tone (effect) after they completed conditioning blocks in which high, medium, and low tones were coupled to images of happy, fearful, and neutral faces. The results replicated those produced previously: it was reported that an effect after a voluntary action occurred earlier, and the preceding action occurred later, compared with trials that used only key presses or tones. Patients had reduced overall binding scores relative to healthy volunteers, suggesting a reduced sense of agency. There was no effect of the emotional stimuli (faces) or other interaction effects. Healthy volunteers with subclinical depressive symptoms had higher overall binding scores. We demonstrate that patients with motor conversion disorder have decreased action‐effect binding for normal voluntary movements compared with healthy volunteers, consistent with the greater experience of lack of control. © 2013 Movement Disorder Societ

Gender disparity and abuse in functional movement disorders: a multi-center case-control study

BACKGROUND: To determine gender differences in rates of sexual and physical abuse in functional movement disorders compared to controls and evaluate if the gender disparity of functional movement disorders is associated with abuse history. METHODS: We performed a retrospective case-control study of self-reported trauma data from 696 patients (512 women) with functional movement disorders from six clinical sites compared to 141 controls (98 women) and population data. Chi-square was used to assess gender and disorder associations; logistic regression was used to model additive effects of abuse and calculate the attributable fraction of abuse to disorder prevalence. RESULTS: Higher rates of sexual abuse were reported by women (35.3%) and men (11.5%) with functional movement disorders compared to controls (10.6% of women; 5.6% of men). History of sexual abuse increased the likelihood of functional movement disorders among women by an odds ratio of 4.57 (95% confidence interval 2.31–9.07; p < 0.0001) and physical abuse by an odds ratio of 2.80 (95% confidence interval 1.53–5.12; p = 0.0007). Population attributable fraction of childhood sexual abuse to functional movement disorders in women was 0.12 (0.05–0.19). No statistically significant associations were found in men, but our cohort of men was underpowered despite including multiple sites. CONCLUSION: Our study suggests that violence against women may account for some of the gender disparity in rates of functional movement disorders. Most people with functional movement disorders do not report a history of abuse, so it remains just one among many relevant risk factors to consider

Gender disparity and abuse in functional movement disorders:a multi-center case-control study

BACKGROUND: To determine gender differences in rates of sexual and physical abuse in functional movement disorders compared to controls and evaluate if the gender disparity of functional movement disorders is associated with abuse history. METHODS: We performed a retrospective case-control study of self-reported trauma data from 696 patients (512 women) with functional movement disorders from six clinical sites compared to 141 controls (98 women) and population data. Chi-square was used to assess gender and disorder associations; logistic regression was used to model additive effects of abuse and calculate the attributable fraction of abuse to disorder prevalence. RESULTS: Higher rates of sexual abuse were reported by women (35.3%) and men (11.5%) with functional movement disorders compared to controls (10.6% of women; 5.6% of men). History of sexual abuse increased the likelihood of functional movement disorders among women by an odds ratio of 4.57 (95% confidence interval 2.31–9.07; p < 0.0001) and physical abuse by an odds ratio of 2.80 (95% confidence interval 1.53–5.12; p = 0.0007). Population attributable fraction of childhood sexual abuse to functional movement disorders in women was 0.12 (0.05–0.19). No statistically significant associations were found in men, but our cohort of men was underpowered despite including multiple sites. CONCLUSION: Our study suggests that violence against women may account for some of the gender disparity in rates of functional movement disorders. Most people with functional movement disorders do not report a history of abuse, so it remains just one among many relevant risk factors to consider