{
  "abstract": "Background No disorder-specific patient-reported outcome measure (PROM) has yet been validated for functional movement disorders (FMDs), leaving a critical gap in clinical care and research.Objective To validate the FMD questionnaire (FMDQ) in a prospectively recruited sample through a multicentre study.Methods Confirmatory factorial analysis (CFA) tested the assumed structure of the questionnaire with factors reflecting severity of motor symptoms, impairment of everyday activities, impact of non-motor symptoms and impairment of social functioning. Internal consistency and floor/ceiling effects were examined. The 36-item short form health survey (SF-36), patient health questionnaire-15 (PHQ-15), the fatigue assessment scale (FAS) and a clinician-rated scale corresponding to motor symptom items of the FMDQ (FMDQ-CR) were used to test criterion and construct validity. The minimally clinically important difference (MCID) was assessed through distribution-based and anchor-based methods in a convenience sample of patients with follow-up assessments.Results Complete datasets from 157 patients were analysed; follow-up assessments were available from 30 patients. CFA confirmed that a four-factor model provides a better fit to the data compared with a more restrictive one-factor model. Internal consistency was appropriate for all factors/subscales. No floor or ceiling effects were detected. Criterion and content validity were supported by significant correlations with respective SF-36 subscores, PHQ-15, FAS and FMDQ-CR. Anchor-based MCID was estimated at 8 to 20 points, with the central value aligning with the distribution-based MCID of 12 points (8% of the total score range).Conclusions The FMDQ is a psychometrically robust PROM, making it a useful tool for clinical practice and treatment trials.",
  "authors": [
    {
      "affiliations": [
        "Department of Neurology, Knappschaft Kliniken University Hospital Bochum, Ruhr University Bochum, Bochum, Germany",
        "Department of Neurology and Centre for Translational and Bahavioral Neurosciences (C-TNBS), University Medicine Essen, University of Duisburg-Essen, Essen, Germany"
      ],
      "name": "Rosa Michaelis"
    },
    {
      "affiliations": [
        "Department of Neurology, Knappschaft Kliniken University Hospital Bochum, Ruhr University Bochum, Bochum, Germany"
      ],
      "name": "Leonie Hagedorn"
    },
    {
      "affiliations": [
        "Institute of Systems Motor Science, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany",
        "Centre of Rare Diseases, University Clinic Schleswig-Holstein, Lübeck, Germany"
      ],
      "name": "Anne Weissbach"
    },
    {
      "affiliations": [
        "Department of Neurology, University Medical Centre Göttingen, Göttingen, Germany",
        "German Centre for Neurodegenerative Diseases (DZNE), Göttingen, Germany"
      ],
      "name": "Christoph van Riesen"
    },
    {
      "affiliations": [
        "Department of Neurology, Christian Albrecht University of Kiel, Kiel, Germany"
      ],
      "name": "Kirsten E Zeuner"
    },
    {
      "affiliations": [
        "Movement Disorders Hospital Beelitz-Heilstätten, Kliniken Beelitz GmbH, Beelitz, Germany"
      ],
      "name": "Tamara Schmidt"
    },
    {
      "affiliations": [
        "Institute of Systems Motor Science, Center of Brain, Behavior and Metabolism (CBBM), University of Lübeck, Lübeck, Germany"
      ],
      "name": "Christina Bolte"
    },
    {
      "affiliations": [
        "Department of Neurology, University Medical Centre Göttingen, Göttingen, Germany"
      ],
      "name": "Felix Bernsdorff"
    },
    {
      "affiliations": [
        "Department of Neurology, University Medical Centre Göttingen, Göttingen, Germany"
      ],
      "name": "Maximilian J Löw"
    },
    {
      "affiliations": [
        "Department of Radiology and Neuroradioloy, Christian Albrecht University of Kiel, Kiel, Germany"
      ],
      "name": "Carl A Gless"
    },
    {
      "affiliations": [
        "Department of Neurology, Christian Albrecht University of Kiel, Kiel, Germany"
      ],
      "name": "Annemarie Reincke"
    },
    {
      "affiliations": [
        "Movement Disorders Hospital Beelitz-Heilstätten, Kliniken Beelitz GmbH, Beelitz, Germany"
      ],
      "name": "Desiree Sykora"
    },
    {
      "affiliations": [
        "Division of Neurology, Saratoga Hospital, Saratoga Springs, New York, USA",
        "Department of Neurology, Albany Medical Centre, Albany, New York, USA"
      ],
      "name": "Kathrin LaFaver"
    },
    {
      "affiliations": [
        "Department of Neurology, Princess Alexandra Hospital, Brisbane, Queensland, Australia",
        "Faculty of Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia"
      ],
      "name": "Alexander C Lehn"
    },
    {
      "affiliations": [
        "Department of Neurology and Centre for Translational and Bahavioral Neurosciences (C-TNBS), University Medicine Essen, University of Duisburg-Essen, Essen, Germany"
      ],
      "name": "Christoph Kleinschnitz"
    },
    {
      "affiliations": [
        "Department of Neurology, Knappschaft Kliniken University Hospital Bochum, Ruhr University Bochum, Bochum, Germany"
      ],
      "name": "Corinna Seliger"
    },
    {
      "affiliations": [
        "Department of Neurology and Centre for Translational and Bahavioral Neurosciences (C-TNBS), University Medicine Essen, University of Duisburg-Essen, Essen, Germany"
      ],
      "name": "Stoyan Popkirov"
    }
  ],
  "title": "Multicentre validation of a patient-reported outcome measure for functional movement disorders",
  "uid": "187ae716-5d5b-5676-b508-f7f91c485b4a"
}