title: Disease adaptation may have decreased quality-of-life responsiveness in patients with chronic progressive neurological disorders.
abstract: OBJECTIVE
  We hypothesized that disease adaptation could be measured in chronic progressive neurological disorders (CPND) through paired longitudinal comparisons of quality of life (QOL) and health status (HS) and of the mental health (MH) and physical health (PH) domains of QOL instruments.
  
  
  METHODS
  We identified 193 quantitative studies of QOL and HS in a systematic review of episodic (END) and chronic progressive (CPND) neurological disorders. Effect size or other responsiveness measures were analyzed in 31 studies that included paired longitudinal comparisons of QOL-HS, MH-PH, or both. Responsiveness means were compared using the paired-sample t-test or sign test.
  
  
  RESULTS
  In 12 paired comparisons, QOL responsiveness was significantly lower than HS (P=.05, sign test). In 53 paired MH-PH effect-size comparisons, MH responsiveness was lower than PH (P=.02, t=2.48, paired sample). Significantly lower MH responsiveness was observed in 28 paired CPND comparisons (P < .01, t=3.86, paired sample) but not in 25 paired END comparisons (P=.50, t=0.68, paired sample).
  
  
  CONCLUSIONS
  Lower responsiveness of QOL in CPND may be related to disease adaptation. Further prospective studies are needed to confirm our findings and to investigate the importance of disease adaptation in the evaluation of neurological disease and in health resource allocation.
authors.affiliation: Mount Sinai Hospital and The University Health Network, Toronto, Ontario, Canada.
authors.forename: Ralph Z
authors.initials: RZ
authors.lastname: Kern
authors.forename: Adalsteinn D
authors.initials: AD
authors.lastname: Brown
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D006305:Health Status Indicators; D006801:Humans; D019636:Neurodegenerative Diseases / Q000503:physiopathology / Q000523:psychology*; D011569:Psychiatric Status Rating Scales; D011788:Quality of Life; D012680:Sensitivity and Specificity