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

• Type of Material: Article
• Authors: Susannah Pick, Kings College London; David G. Anderson, University of Witwatersrand; Ali A. Asadi-Pooya, Shiraz University of Medical Science; Selma Aybek, University Hospital of Bern; Gaston Baslet, Harvard University; Bastiaan R. Bloem, Radboud University Nijmegen; Abigail Bradley-Westguard, University of Manchester; Richard J. Brown, University of Manchester; Karen Rommelfanger, Emory University; Timothy R. Nicholson, Kings College London
• Language: English
• Date: 2020-06-01
• Publisher: BMJ Publishing Group
• Publication Version: Final Published Version
• Copyright Statement: © Author(s) (or their employer(s)) 2020.
• License: Creative Commons Attribution-NonCommercial 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1136/jnnp-2019-322180
• Title of Journal or Parent Work: Journal of Neurology, Neurosurgery, and Psychiatry
• Volume: 91
• Issue: 6
• Start Page: 638
• End Page: 649
• Grant/Funding Information: TRN and SPi were also funded by an NIHR clinician scientist fellowship. GN also received funding from the NIHR.; She also received PhD funding from King’s College London and a King’s Institute of Psychiatry, Psychology and Neuroscience (IoPPN) Clinician Investigator Scholarship.; AJE received grant support from the National Institutes of Health (NIH) and the Michael J Fox Foundation.; RCK received an NIHR Academic Clinical Fellowship in General Adult Psychiatry and a Royal College of Psychiatrists Gosling Fellowship.; LHG reported salary support from the UK National Institute for Health Research (NIHR) Maudsley Biomedical Research Centre at the South London and Maudsley NHS Foundation Trust and King’s College London.; MH was supported by the National Institute of Neurological Disorders and Stroke Intramural Programme (NIH, USA).; TS received support from Ministry of Health of the Czech Republic (grant number AZV ČR 16-29651).
• Keywords: Life Sciences & Biomedicine; Psychiatry; Psychogenic nonepileptic seizures; Science & Technology; Clinical Neurology; functional neurological disorder; Rating scale; Movement disorders; clinical neurology; Quality of life; Symptoms; conversion disorder; Anxiety; Randomized controlled trial; neuropsychiatry; Neurosciences & Neurology; Epilepsy; movement disorders; Form health survey; Therapy; Surgery
• Research Categories: Biology, Neuroscience; Health Sciences, Mental Health; Psychology, Behavioral

Abstract

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.