title: Measurement of neurodevelopmental changes in children treated with radiation for brain tumors: what is a true 'baseline?'
abstract: OBJECTIVE
  To review the various ways in which baseline neuropsychological functioning is measured in the extant literature on pediatric brain tumors, describe the pros and cons of each approach, and increase the awareness of researchers as to the implications of each.
  
  
  METHODS
  We reviewed the literature from 1993 to 2013, and classified studies by baseline approach and explicitness of selection of approach.
  
  
  RESULTS
  There are multiple approaches to operationalizing baseline levels of ability and to assess change from baseline. Each approach has strengths and weaknesses, and selection may depend on the question under investigation. Approaches to baseline estimation varied widely with a trend over time toward reliance on statistical modeling. Researchers were often insufficiently explicit about the reasons for adopting a particular approach. The common use of standardized scores requires caution as they obscure critical inferential limitations about change and magnitude of change. Some viable approaches were infrequently used, such as actuarial prediction formulas. Multiple simultaneous methods akin to theory testing and formal methods of construct validation could enhance scientific yield since all approaches are fallible.
  
  
  CONCLUSIONS
  Estimating baseline neuropsychological functioning is very challenging, particularly when it concerns children in the preschool years. Nevertheless, it is a crucial methodological decision with important implications for the interpretation of research findings that needs to be dealt with explicitly.
authors.affiliation: a Department of Pediatrics , Baylor College of Medicine, Texas Children's Hospital , Houston , TX , USA.
authors.forename: M Douglas
authors.initials: MD
authors.lastname: Ris
authors.affiliation: a Department of Pediatrics , Baylor College of Medicine, Texas Children's Hospital , Houston , TX , USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Grosch
authors.affiliation: b Department of Psychology , University of Houston , Houston , TX , USA.
authors.forename: Jack M
authors.initials: JM
authors.lastname: Fletcher
authors.affiliation: b Department of Psychology , University of Houston , Houston , TX , USA.
authors.forename: Paras
authors.initials: P
authors.lastname: Metah
authors.affiliation: a Department of Pediatrics , Baylor College of Medicine, Texas Children's Hospital , Houston , TX , USA.
authors.forename: Lisa S
authors.initials: LS
authors.lastname: Kahalley
mesh_terms: D000293:Adolescent; D001921:Brain / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D001932:Brain Neoplasms / Q000523:psychology* / Q000532:radiotherapy*; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D009483:Neuropsychological Tests
keywords: Pediatric brain tumors; childhood cancer; late effects; neurocognitive; neuropsychological outcome