title: Reproducibility of two four-point clinical severity scores for lateral canthal lines (crow's feet).
abstract: BACKGROUND
  Several clinical scoring systems have been used to evaluate the efficacy of botulinum toxin A in the treatment of hyperkinetic wrinkles. So far very few have been investigated for their reproducibility.
  
  
  OBJECTIVE
  The aim of this study was to investigate the reproducibility of two clinical four-point scales for lateral canthal lines (crow's feet), at rest and at maximum smile.
  
  
  METHODS
  Based on standardized photographs, a consensus atlas depicting the different severity grades [from 0 (none) to 3 (severe)] was developed. After training based on the atlas, 49 photographs at rest and 48 at maximum smile were graded by the same group of investigators on 2 consecutive days (n=9 on Day 1; n=8 on Day 2). The scores were compared for reproducibility using kappa statistics.
  
  
  RESULTS
  Overall, reproducibility was good for both scales. Interobserver reproducibility showed an agreement of 0.6 at rest and 0.58 at maximum smile (unweighted kappa). Intraobserver reproducibility showed an agreement between 0.47 and 0.86 at rest and between 0.62 and 0.81 at maximum smile (unweighted kappa). Using weighted kappa analysis, the agreement ranged between 0.63 and 0.91 at rest and between 0.71 and 0.85 at maximum smile.
  
  
  CONCLUSIONS
  The clinical scales using scores of 0 to 3 for crow's feet, both at rest and at maximum smile, show a good inter- and intraobserver reproducibility. The use of these scores in clinical trials can be recommended.
authors.affiliation: Department of Dermatology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Hund
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ascher
authors.forename: Berthold
authors.initials: B
authors.lastname: Rzany
mesh_terms: D003357:Cosmetic Techniques; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010781:Photography; D015203:Reproducibility of Results; D015595:Skin Aging