title: Confirmatory factor analysis of the Cornell scale for depression in dementia among patient with dementia of various degrees.
abstract: BACKGROUND
  Depression in dementia is difficult to diagnose. The psychometric qualities of the Cornell scale for depression in dementia and whether depression varies depending on the dementia severity are still controversial.
  
  
  METHODS
  Cross-sectional study of memory clinic and nursing-home patients.
  
  
  METHODS
  A sample of 1682 patients (750 from memory clinics and 932 from nursing homes) with Clinical dementia rating scale score of one or higher was evaluated with the Cornell scale. The sample was randomly divided into two groups. Exploratory factor analysis was performed on one-half of the patients and confirmatory factor analysis on the other half. It was further analysed whether the scores of the sub-scales differed across CDR score.
  
  
  RESULTS
  A five-factor solution fitted the data best according to both the exploratory and confirmatory factor analysis: 'mood', 'physical', 'cyclic', 'retardation' and 'behaviour'. Further, it was found that the sum score of the Cornell scale differs significantly across dementia severity (p=0.018). The mood and the cyclic sub-scales scores did not vary across dementia severity, unlike the three remaining sub-scales scores.
  
  
  CONCLUSIONS
  A five-factor solution of the Cornell scale best fitted the data according to both exploratory and confirmatory factor analysis. The mood and cyclic factors' scores did not vary across dementia severity, and this might suggest that they are the core symptoms of depression that are equally present regardless of dementia severity. The other factors scores were higher in severe dementia, which might suggest that these factors are related to the dementia.
authors.affiliation: Norwegian advisory unit for Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway; Center for Alzheimer's Disease, Institute of Psychiatry, Federal University of Rio de Janeiro, Brazil. Electronic address: maria.barca@aldringoghelse.no.
authors.forename: Maria Lage
authors.initials: ML
authors.lastname: Barca
authors.affiliation: Norwegian advisory unit for Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway.
authors.forename: Knut
authors.initials: K
authors.lastname: Engedal
authors.affiliation: Norwegian advisory unit for Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway; Research Centre for Old Age Psychiatric Research, Innlandet Hospital Trust, Ottestad, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Selbaek
authors.affiliation: Norwegian advisory unit for Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway.
authors.forename: Anne-Brita
authors.initials: AB
authors.lastname: Knapskog
authors.affiliation: Center for Alzheimer's Disease, Institute of Psychiatry, Federal University of Rio de Janeiro, Brazil.
authors.forename: Jerson
authors.initials: J
authors.lastname: Laks
authors.affiliation: Center for Alzheimer's Disease, Institute of Psychiatry, Federal University of Rio de Janeiro, Brazil.
authors.forename: Evandro
authors.initials: E
authors.lastname: Coutinho
authors.affiliation: Institute of Clinical Medicine, Campus Ahus, University of Oslo, Norway; HØKH, Research Centre, Akershus University Hospital, Norway.
authors.forename: Jurate Šaltytė
authors.initials: JŠ
authors.lastname: Benth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000554:Ambulatory Care Facilities; D003430:Cross-Sectional Studies; D003704:Dementia / Q000150:complications* / Q000175:diagnosis / Q000523:psychology*; D003863:Depression / Q000150:complications* / Q000175:diagnosis*; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics
keywords: Cornell scale; Dementia; Depression; Factor analysis; Memory clinic; Nursing home