title: Methods in Neuroepidemiology Characterization of European Longitudinal Cohort Studies in Parkinson's Disease--Report of the JPND Working Group BioLoC-PD.
abstract: BACKGROUND
  Enormous effort is being put into the identification and characterization of symptoms that may be used as predictive and progression markers in Parkinson's disease (PD). An impressive number of PD patients and individuals at risk for or in the prodromal stage of PD are currently followed in longitudinal studies; however, there does not exist an overview on the kind of markers evaluated and the assessments used.
  
  
  METHODS
  Information on the design, sample size, evaluated markers and assessments of 21 studies of the Joint Programme - Neurodegenerative Disease Research BioLoC-PD working group were collected by questionnaire. The studies were classified into at risk/prodromal or clinical PD cohorts. The assessments were grouped into quantitative assessments, investigator-rated assessments, investigator interviews, patient-rated questionnaires and caregiver-rated questionnaires.
  
  
  RESULTS
  Compilation of these data revealed an interesting consensus on evaluated markers, but there was an enormous variability of assessments. Furthermore, there is a remarkable similarity in the markers assessed and evaluation methods applied in the risk/prodromal and clinical PD cohorts.
  
  
  CONCLUSIONS
  The inventory of the longitudinal cohorts that are part of the BioLoC-PD consortium reveals that there is a growing consensus on the markers that should be assessed in longitudinal cohort studies in PD. However, controversy still exists on the specific type of assessment. To allow comparison of data and common analyses it will be essential to harmonize scales and assessment outcomes.
authors.affiliation: Center of Neurology, Department of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Lerche
authors.forename: Inga
authors.initials: I
authors.lastname: Liepelt-Scarfone
authors.forename: Guido
authors.initials: G
authors.lastname: Alves
authors.forename: Paolo
authors.initials: P
authors.lastname: Barone
authors.forename: Stefanie
authors.initials: S
authors.lastname: Behnke
authors.forename: Yoav
authors.initials: Y
authors.lastname: Ben-Shlomo
authors.forename: Henk
authors.initials: H
authors.lastname: Berendse
authors.forename: David
authors.initials: D
authors.lastname: Burn
authors.forename: Richard
authors.initials: R
authors.lastname: Dodel
authors.forename: Donald
authors.initials: D
authors.lastname: Grosset
authors.forename: Sebastian
authors.initials: S
authors.lastname: Heinzel
authors.forename: Michele
authors.initials: M
authors.lastname: Hu
authors.forename: Meike
authors.initials: M
authors.lastname: Kasten
authors.forename: Rejko
authors.initials: R
authors.lastname: Krüger
authors.forename: Walter
authors.initials: W
authors.lastname: Maetzler
authors.forename: Marcello
authors.initials: M
authors.lastname: Moccia
authors.forename: Brit
authors.initials: B
authors.lastname: Mollenhauer
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Oertel
authors.forename: Benjamin
authors.initials: B
authors.lastname: Roeben
authors.forename: Ulrike
authors.initials: U
authors.lastname: Sünkel
authors.forename: Uwe
authors.initials: U
authors.lastname: Walter
authors.forename: Karin
authors.initials: K
authors.lastname: Wirdefeldt
authors.forename: Daniela
authors.initials: D
authors.lastname: Berg
mesh_terms: D015415:Biomarkers; D018450:Disease Progression; D005060:Europe; D006801:Humans; D008137:Longitudinal Studies; D010300:Parkinson Disease / Q000175:diagnosis*; D062706:Prodromal Symptoms; D012107:Research Design
chemical_list: D015415:Biomarkers