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

Abstract

ObjectivesWe 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.MethodsA 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.ResultsFive 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).ConclusionsThere 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.

Psychologically informed physiotherapy as part of a multidisciplinary rehabilitation program for children and adolescents with functional neurological disorder: Physical and mental health outcomes

“…The WeeFIM does not provide, however, any way of teasing out the impact of comorbid pain (present in up to two‐thirds of our patients) and global impairment of function secondary to comorbid mental health disorders (also present in approximately two‐thirds of our patients). Valid and reliable measures – ones that can, in a population of paediatric FND patients, identify both caseness and particular dimensions of mental health – have yet to be identified 35,36 . Finally, decisions concerning the need for, and allocation of, public health resources would benefit from further research to identify the actual costs, both financial and regarding the wear and tear on professional staff, of interventions for children with different levels of complexity and chronicity.…”

“…Valid and reliable measuresones that can, in a population of paediatric FND patients, identify both caseness and particular dimensions of mental healthhave yet to be identified. 35,36 Finally, decisions concerning the need for, and allocation of, public health resources would benefit from further research to identify the actual costs, both financial and regarding the wear and tear on professional staff, of interventions for children with different levels of complexity and chronicity.…”

Trial Of Neurostimulation In Conversion Symptoms (TONICS): a feasibility randomised controlled trial of transcranial magnetic stimulation for functional limb weakness

“…This measure has recently been recommended as a primary outcome measure in FND treatment studies. 17 …”

Effects ofTPH2gene variation and childhood trauma on the clinical and circuit-level phenotype of functional movement disorders

“…15 These clinician-rated scales are considered among the most common and useful tools to evaluate the severity of psychiatric symptoms across different functional neurological disorders. 16 Participants also completed the Childhood Trauma Questionnaire (CTQ), 17 which is one of the most widely used self-reports of early adversity used in research settings. This questionnaire measures five types of maltreatment: emotional, physical, and sexual abuse, and emotional and physical neglect, and has been shown to be a reliable, internally consistent and valid instrument.…”