title: Development and validation of a computerized visual analog scale for the measurement of pain in patients with patellofemoral pain syndrome.
abstract: OBJECTIVE
  To develop a computerized visual analog scale (cVAS) system and determine if it could be used in place of the traditional 100-mm paper-based visual analog scale (pVAS) method for the measurement of pain in patients with patellofemoral pain syndrome (PFPS).
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Biomechanics laboratory.
  
  
  METHODS
  Thirty-six runners diagnosed with PFPS.
  
  
  METHODS
  A cVAS system was custom-coded for this study. Participants completed both the cVAS survey and a pVAS survey that measured usual knee pain during running, walking, prolonged sitting, stair ascent, stair descent, and squatting movements. Thus, 216 paired measurements were made in total.
  
  
  METHODS
  Pearson correlation coefficients and slopes of the line of best fit were calculated to assess the relationship between cVAS and pVAS scores, and Bland-Altman plots were constructed to determine cVAS agreement to pVAS scores.
  
  
  RESULTS
  All cVAS measures were highly correlated to pVAS scores (all r values were >0.9), and slopes were always near 1.0. Bland-Altman plots demonstrated that there was good agreement between the 2 methods.
  
  
  CONCLUSIONS
  The cVAS system that was developed is a valid method for measurement of pain in patients with PFPS. Further use of the cVAS for studies involving PFPS is supported.
authors.affiliation: Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. lewinson@ucalgary.ca
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Lewinson
authors.forename: J Preston
authors.initials: JP
authors.lastname: Wiley
authors.forename: Jay T
authors.initials: JT
authors.lastname: Worobets
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Stefanyshyn
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010147:Pain Measurement; D046788:Patellofemoral Pain Syndrome / Q000175:diagnosis*