title: Measuring quality of life in PSP: the PSP-QoL.
abstract: OBJECTIVE
  To develop a new patient-reported outcome measure for progressive supranuclear palsy (PSP) and to test its psychometric properties.
  
  
  METHODS
  First, the authors generated a pool of potential scale items from in-depth patient interviews. Second, the authors administered these items, in the form of a questionnaire, to a sample of people with PSP and traditional psychometric methods were used to develop a rating scale satisfying standard criteria for reliability and validity. Third, the authors examined the psychometric properties of the rating scale in a second sample.
  
  
  RESULTS
  In stage 1, a pool of 87 items was generated from 27 patient interviews. In stage 2, a scale with two subscales (physical, 22 items; mental, 23 items), satisfying standard criteria for reliability and validity, was developed from the response data of 225 patients with PSP. In stage 3, the scale was examined in 188 people with PSP. Missing data were low, scores in both subscales were evenly distributed, floor and ceiling effects were small. Reliability was high (Cronbach's alpha 0.93, 0.95; test-retest 0.95, 0.92). Validity was supported by the interscale intercorrelation (0.60), factor analysis, and the magnitude and pattern of correlations with four other rating scales, disease severity, and disease duration. The psychometric properties of the new scale were similar in the United Kingdom and North America, and in clinic- and community-based samples studied.
  
  
  CONCLUSIONS
  The Progressive Supranuclear Palsy Quality of Life scale (PSP-QoL) may be a helpful patient-reported scale for clinical trials and studies in PSP.
authors.affiliation: Royal Free and University College Medical School, Department of Clinical Neurosciences, Institute of Neurology, University College London, UK. a.schrag@medsch.ucl.ac.uk
authors.forename: A
authors.initials: A
authors.lastname: Schrag
authors.forename: C
authors.initials: C
authors.lastname: Selai
authors.forename: N
authors.initials: N
authors.lastname: Quinn
authors.forename: A
authors.initials: A
authors.lastname: Lees
authors.forename: I
authors.initials: I
authors.lastname: Litvan
authors.forename: A
authors.initials: A
authors.lastname: Lang
authors.forename: Y
authors.initials: Y
authors.lastname: Poon
authors.forename: J
authors.initials: J
authors.lastname: Bower
authors.forename: D
authors.initials: D
authors.lastname: Burn
authors.forename: J
authors.initials: J
authors.lastname: Hobart
mesh_terms: D000368:Aged; D006801:Humans; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D013494:Supranuclear Palsy, Progressive / Q000503:physiopathology / Q000523:psychology*; D011795:Surveys and Questionnaires / Q000592:standards*