title: Rasch-ionale for neurologists.
abstract: Outcome measures are considered the most important tools to monitor patients' outcome in both clinical and research settings. Measuring the clinical state of patients is a fundamental part of our daily clinical practice and research that sometimes is taken for granted. In peripheral neuropathies, there are many scales available, but most of these are at the ordinal level. This paper will systematically address the types of scales available (being nominal, ordinal, interval, or ratio data-based) in terms of their strengths and weaknesses. The differences between classical test theory-based and modern test method-based outcome measures will be addressed with emphasis on Rasch methodology. Various steps will be highlighted as part of the evaluation and construction of outcome measures using the Rasch method, with the aim to increase the knowledge and utility of this technique. We argue that Rasch-built outcome measures should be used for future studies in neuromuscular disorders and their method of construction could be easily extrapolated to other neurological illnesses.
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, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Mieke C E
authors.initials: MC
authors.lastname: Hermans
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, 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, Maastricht University Medical Center, Maastricht, The Netherlands.|Department of Neurology, Erasmus Medical Center Rotterdam, Rotterdam.|Department of Neurology, Spaarne Hospital, Hoofddorp, The Netherlands.
authors.forename: Ingemar S J
authors.initials: IS
authors.lastname: Merkies
authors.affiliation: Institute of Neuroscience (IoNS), Université catholique de Louvain.|Department of Physical and Rehabilitation Medicine, Cliniques universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Jean-L
authors.initials: JL
authors.lastname: Thonnard
mesh_terms: D004185:Disability Evaluation; D006801:Humans; D009462:Neurology; D017063:Outcome Assessment, Health Care; D010523:Peripheral Nervous System Diseases / Q000628:therapy*; D015203:Reproducibility of Results
keywords: Rasch; classical test theory; item response theory; measurement; outcome measure