title: Factor analysis and Rasch analysis of the Zarit Burden Interview for acquired brain injury carer research.
abstract: OBJECTIVE
  To examine the dimensionality of the Zarit Burden Interview in a sample of carers of adults with acquired brain injury.
  
  
  METHODS
  A cross-sectional UK survey using postal questionnaires.
  
  
  METHODS
  A sample of 222 carers; 43 men (19.4%) and 179 women (80.6%); mean age 54 years. Types of brain injury included traumatic brain injury (49.5%), stroke (25.9%), brain infection (17.3%), hypoxia (4.1%), and "other" (3.2%).
  
  
  METHODS
  Exploratory and confirmatory factor analysis and Rasch analysis.
  
  
  RESULTS
  Unidimensionality was tested using confirmatory factor analysis, which showed a poor fit. The underlying structure of the Zarit Burden Interview was explored using principal components analysis and varimax rotation. This revealed 3 factors, although 1 comprised only 2 items. The 2 major factors identified were personal strain and role strain. They were then examined using Rasch analysis, which identified 2 brief and reliable unidimensional scales. There was no evidence of differential item functioning for different types of carer/brain injury.
  
  
  CONCLUSIONS
  The Zarit Burden Interview is a promising mea-sure for the assessment of burden in carers of people with an acquired brain injury. It offers 2 reliable, brief subscales of personal strain and role strain for this purpose. However, it remains for these 2 brief subscales to be validated clinically in future research.
authors.affiliation: Department of Palliative Care, Policy and Rehabilitation, School of Medicine, King's College London, London, UK. richard.siegert@kcl.ac.uk
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Siegert
authors.forename: Diana M
authors.initials: DM
authors.lastname: Jackson
authors.forename: Alan
authors.initials: A
authors.lastname: Tennant
authors.forename: Lynne
authors.initials: L
authors.lastname: Turner-Stokes
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000451:nursing* / Q000523:psychology; D017028:Caregivers / Q000523:psychology*; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D011594:Psychometrics; D012380:Role; D020521:Stroke / Q000451:nursing / Q000523:psychology; D011795:Surveys and Questionnaires