title: Development of the multiple sclerosis (MS) early mobility impairment questionnaire (EMIQ).
abstract: The Early Mobility Impairment Questionnaire (EMIQ) was developed to facilitate early identification of mobility impairments in multiple sclerosis (MS) patients. We describe the initial development of the EMIQ with a focus on the psychometric evaluation of the questionnaire using classical and item response theory methods. The initial 20-item EMIQ was constructed by clinical specialists and qualitatively tested among people with MS and physicians via cognitive interviews. Data from an observational study was used to make additional updates to the instrument based on exploratory factor analysis (EFA) and item response theory (IRT) analysis, and psychometric analyses were performed to evaluate the reliability and validity of the final instrument's scores and screening properties (i.e., sensitivity and specificity). Based on qualitative interview analyses, a revised 15-item EMIQ was included in the observational study. EFA, IRT and item-to-item correlation analyses revealed redundant items which were removed leading to the final nine-item EMIQ. The nine-item EMIQ performed well with respect to: test-retest reliability (ICC = 0.858); internal consistency (α = 0.893); convergent validity; and known-groups methods for construct validity. A cut-point of 41 on the 0-to-100 scale resulted in sufficient sensitivity and specificity statistics for viably identifying patients with mobility impairment. The EMIQ is a content valid and psychometrically sound instrument for capturing MS patients' experience with mobility impairments in a clinical practice setting. Additional research is suggested to further confirm the EMIQ's screening properties over time.
authors.affiliation: Center of Clinical Neuroscience, Neurological University Clinic Carl Gustav Carus, TU Dresden, Germany.
authors.forename: Tjalf
authors.initials: T
authors.lastname: Ziemssen
authors.affiliation: Biogen, Cambridge, MA, USA.
authors.forename: Glenn
authors.initials: G
authors.lastname: Phillips
authors.affiliation: University of Mississippi, University, MS, USA.
authors.forename: Ruchit
authors.initials: R
authors.lastname: Shah
authors.affiliation: Adelphi Values USA, Boston, MA, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Mathias
authors.affiliation: Adelphi Values USA, Boston, MA, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Foley
authors.affiliation: Adelphi Values USA, Boston, MA, USA.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Coon
authors.affiliation: Adelphi Values USA, Boston, MA, USA.
authors.forename: Rohini
authors.initials: R
authors.lastname: Sen
authors.affiliation: Biogen, Cambridge, MA, USA. andrew.lee@biogen.com.
authors.forename: Andrew
authors.identifier: http://orcid.org/0000-0002-4327-2749
authors.initials: A
authors.lastname: Lee
authors.affiliation: Biogen, Cambridge, MA, USA.
authors.forename: Sonalee
authors.initials: S
authors.lastname: Agarwal
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D000704:Analysis of Variance; D004185:Disability Evaluation; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000175:diagnosis / Q000209:etiology*; D009103:Multiple Sclerosis / Q000150:complications* / Q000175:diagnosis*; D011594:Psychometrics; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires
keywords: EMIQ; MS; Multiple sclerosis; Screener