title: Principal component analysis of the Norwegian version of the quality of life in late-stage dementia scale.
abstract: OBJECTIVE
  To investigate which factors the Quality of Life in Late-Stage Dementia (QUALID) scale holds when used among people with dementia (pwd) in nursing homes and to find out how the symptom load varies across the different severity levels of dementia.
  
  
  METHODS
  We included 661 pwd [mean age ± SD, 85.3 ± 8.6 years; 71.4% women]. The QUALID and the Clinical Dementia Rating (CDR) scale were applied. A principal component analysis (PCA) with varimax rotation and Kaiser normalization was applied to test the factor structure. Nonparametric analyses were applied to examine differences of symptom load across the three CDR groups.
  
  
  RESULTS
  The mean QUALID score was 21.5 (±7.1), and the CDR scores of the three groups were 1 in 22.5%, 2 in 33.6% and 3 in 43.9%. The results of the statistical measures employed were the following: Crohnbach's α of QUALID, 0.74; Bartlett's test of sphericity, p <0.001; the Kaiser-Meyer-Olkin measure, 0.77. The PCA analysis resulted in three components accounting for 53% of the variance. The first component was 'tension' ('facial expression of discomfort', 'appears physically uncomfortable', 'verbalization suggests discomfort', 'being irritable and aggressive', 'appears calm', Crohnbach's α = 0.69), the second was 'well-being' ('smiles', 'enjoys eating', 'enjoys touching/being touched', 'enjoys social interaction', Crohnbach's α = 0.62) and the third was 'sadness' ('appears sad', 'cries', 'facial expression of discomfort', Crohnbach's α 0.65). The mean score on the components 'tension' and 'well-being' increased significantly with increasing severity levels of dementia.
  
  
  CONCLUSIONS
  Three components of quality of life (qol) were identified. Qol decreased with increasing severity of dementia.
authors.affiliation: Norwegian Centre for Ageing and Health, Vestfold Hospital Trust, Tønsberg, Norway.
authors.forename: Marit
authors.initials: M
authors.lastname: Mjørud
authors.forename: Marit
authors.initials: M
authors.lastname: Kirkevold
authors.forename: Janne
authors.initials: J
authors.lastname: Røsvik
authors.forename: Knut
authors.initials: K
authors.lastname: Engedal
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003704:Dementia / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D009735:Nursing Homes; D025341:Principal Component Analysis; D011788:Quality of Life / Q000523:psychology*; D012720:Severity of Illness Index