title: Outcome measures in MMN revisited: further improvement needed.
abstract: The objectives of this study were to provide an overview of the outcome measures (OMs) applied in clinical trials in multifocal motor neuropathy (MMN) and to determine the responsiveness of a core set of selected OMs as part of the peripheral neuropathy outcome measures standardization (PeriNomS) study. The following OMs were serially applied in 26 patients with newly diagnosed or relapsing MMN, receiving intravenous immunoglobulin (assessments: T0/T3/T12 months): 14 muscle pairs MRC (Medical Research Council) scale, the Neuropathy Impairment Scale motor-subset, a self-evaluation scale, grip strength, and MMN-RODS© (Rasch-built overall disability scale). All data, except the grip strength, were subjected to Rasch analyses before determining responsiveness. For grip strength, responsiveness was examined using a combined anchor- (SF-36 question-2) and distribution-based (½ × SD) minimum clinically important difference (MCID) techniques, determining the proportion of patients exceeding both the identified cut-offs. For the remaining scales, the magnitude of change for each patient on each scale was determined using the MCID related to the individual SE (responder definition: MCID-SE ≥ 1.96). Overall, a great assortment of measures has been used in MMN trials with different responsiveness definitions. For the selected OMs, responsiveness was poor and only seen in one fourth to one third of the patients, the grip strength being more responsive. Despite the efforts taken to standardize outcome assessment, further clinimetric responsiveness studies are needed in MMN.
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Mariëlle H J
authors.initials: MH
authors.lastname: Pruppers
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Thomas H P
authors.initials: TH
authors.lastname: Draak
authors.affiliation: Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Els K
authors.initials: EK
authors.lastname: Vanhoutte
authors.affiliation: Department of Neurology, Rudolf Magnus Institute of Neuroscience University Medical Center, Utrecht, The Netherlands.
authors.forename: W-Ludo
authors.initials: WL
authors.lastname: Van der Pol
authors.affiliation: Department of Neurology, St. Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA, USA.
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Gorson
authors.affiliation: Department of Neurology, Hôpital de la Salpêtrière, Paris, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Léger
authors.affiliation: Department of Neurological Sciences, Milan University, Humanitas Clinical Institute, Rozzano, Milan, Italy.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Nobile-Orazio
authors.affiliation: Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Lewis
authors.affiliation: Department of Neurology, Rudolf Magnus Institute of Neuroscience University Medical Center, Utrecht, The Netherlands.
authors.forename: Leonard H
authors.initials: LH
authors.lastname: van den Berg
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Catharina G
authors.initials: CG
authors.lastname: Faber
authors.affiliation: Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.|Department of Neurology, Spaarne Hospital, Hoofddorp, The Netherlands.
authors.forename: Ingemar S J
authors.initials: IS
authors.lastname: Merkies
mesh_terms: D000328:Adult; D000368:Aged; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use*; D007155:Immunologic Factors / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011115:Polyneuropathies / Q000188:drug therapy*
chemical_list: D016756:Immunoglobulins, Intravenous; D007155:Immunologic Factors
keywords: MMN; outcome measure