title: Declines in the diagnosis of primary progressive MS: A critical change in phenotype or critical measurement error?
authors.affiliation: Department of Biostatistics, School of Public Health, The University of Alabama at Birmingham, Birmingham, AL, USA cutterg@uab.edu.
authors.forename: Gary R
authors.initials: GR
authors.lastname: Cutter
authors.affiliation: Department of Biostatistics, Washington University in St. Louis, Saint Louis, MO, USA.
authors.forename: Amber
authors.initials: A
authors.lastname: Salter
authors.affiliation: Departments of Internal Medicine and Community Health Sciences, University of Manitoba, Winnipeg, MB, Canada; Multiple Sclerosis Clinic, Winnipeg, MB, Canada.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Marrie
mesh_terms: D015331:Cohort Studies; D006801:Humans; D009103:Multiple Sclerosis; D020528:Multiple Sclerosis, Chronic Progressive; D010641:Phenotype