title: Does the Order of Item Difficulty of the Addenbrooke's Cognitive Examination Add Anything to Subdomain Scores in the Clinical Assessment of Dementia?
abstract: BACKGROUND
  The Addenbrooke's Cognitive Examination (ACE) is used to measure cognition across a range of domains in dementia. Identifying the order in which cognitive decline occurs across items, and whether this varies between dementia aetiologies could add more information to subdomain scores.
  
  
  METHODS
  ACE-Revised data from 350 patients were split into three groups: Alzheimer's type (n = 131), predominantly frontal (n = 119) and other frontotemporal lobe degenerative disorders (n = 100). Results of factor analysis and Mokken scaling analysis were compared.
  
  
  RESULTS
  Principal component analysis revealed one factor for each group. Confirmatory factor analysis found that the one-factor model fit two samples poorly. Mokken analyses revealed different item ordering in terms of difficulty for each group.
  
  
  CONCLUSIONS
  The different patterns for each diagnostic group could aid in the separation of these different types of dementia.
authors.affiliation: Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh, UK ; Department of Psychology, University of Edinburgh, Edinburgh, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: McGrory
authors.affiliation: Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh, UK ; Geriatric Medicine Unit, University of Edinburgh, Edinburgh, UK ; Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK.
authors.forename: John M
authors.initials: JM
authors.lastname: Starr
authors.affiliation: Geriatric Medicine Unit, University of Edinburgh, Edinburgh, UK ; Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK.
authors.forename: Susan D
authors.initials: SD
authors.lastname: Shenkin
authors.affiliation: Department of Psychology, University of Edinburgh, Edinburgh, UK.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Austin
authors.affiliation: Neuroscience Research Australia, University of New South Wales, Sydney, N.S.W., Australia ; School of Medical Sciences, University of New South Wales, Sydney, N.S.W., Australia.
authors.forename: John R
authors.initials: JR
authors.lastname: Hodges
keywords: Addenbrooke's Cognitive Examination; Dementia; Hierarchical scales; Item response theory; Mokken scaling