title: Inter-Rater Agreement in the Clinical Diagnosis of Essential Tremor: Data from the NEDICES-2 Pilot Study.
abstract: BACKGROUND
  Our aim was to assess the diagnostic agreement among the neurologists in the Neurological Disorders in Central Spain 2 (NEDICES-2) study; these neurologists were assigning diagnoses of essential tremor (ET) vs. no ET.
  
  
  METHODS
  Clinical histories and standardized video-taped neurological examinations of 26 individuals (11 ET, seven Parkinson's disease, three diagnostically unclear, four normal, one with a tremor disorder other than ET) were provided to seven consultant neurologists, six neurology residents, and five neurology research fellows (18 neurologists total). For each of the 26 individuals, neurologists were asked to assign a diagnosis of "ET" or "no ET" using diagnostic criteria proposed by the Movement Disorders Society (MDS). Inter-rater agreement was assessed both with percent concordance and non-weighted κ statistics.
  
  
  RESULTS
  Overall κ was 0.61 (substantial agreement), with no differences between consultant neurologists (κ = 0.60), neurology residents (κ = 0.61), and neurology research fellows (κ = 0.66) in subgroup analyses. Subanalyses of agreement only among those 15 subjects with a previous diagnosis of ET (11 patients) and those with a previous diagnosis of being normal (four individuals) showed an overall κ of 0.51 (moderate agreement).
  
  
  CONCLUSIONS
  In a population-based epidemiological study, substantial agreement was demonstrated for the diagnosis of ET among neurologists of different levels of expertise. However, agreement was lower than that previously reported using the Washington Heights-Inwood Genetic Study of Essential Tremor criteria, and a head-to-head comparison is needed to assess which is the tool of choice in epidemiological research in ET.
authors.affiliation: Neurology Department, University Hospital "12 de Octubre", Madrid, Spain ; Research Institute, University Hospital "12 de Octubre" (i+12), Madrid, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Sierra-Hidalgo
authors.affiliation: Research Institute, University Hospital "12 de Octubre" (i+12), Madrid, Spain.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Romero
authors.affiliation: Neurology Department, University Hospital "12 de Octubre", Madrid, Spain ; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain ; Department of Medicine, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
authors.forename: Felix
authors.initials: F
authors.lastname: Bermejo-Pareja
authors.affiliation: Research Institute, University Hospital "12 de Octubre" (i+12), Madrid, Spain.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Sánchez-Ferro
authors.affiliation: Neurology Department, University Hospital "12 de Octubre", Madrid, Spain ; Department of Medicine, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Hernández-Gallego
authors.affiliation: Neurology Department, University Hospital "12 de Octubre", Madrid, Spain ; Department of Medicine, Faculty of Medicine, Universidad Complutense, Madrid, Spain.
authors.forename: Ignacio J
authors.initials: IJ
authors.lastname: Posada
authors.affiliation: Neurology Department, University Hospital "12 de Octubre", Madrid, Spain.
authors.forename: Julián
authors.initials: J
authors.lastname: Benito-León
authors.affiliation: Gertrude H Sergievsky Center, Columbia University, New York, New York, United States of America ; Department of Epidemiology, Columbia University, New York, New York, United States of America ; Department of Neurology, Columbia University, New York, New York, United States of America ; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, United States of America.
authors.forename: Elan D
authors.initials: ED
authors.lastname: Louis
keywords: Tremor, essential tremor; clinical diagnosis; inter-rater agreement; reliability