Development and Validation of a Photonumeric Scale for Evaluation of Transverse Neck Lines.

Abstract

BACKGROUNDA validated scale is needed for objective and reproducible comparisons of horizontal neck lines before and after treatment in practice and clinical studies.OBJECTIVETo describe the development and validation of the 5-point photonumeric Allergan Transverse Neck Lines Scale.METHODSThe Allergan Transverse Neck Lines Scale was developed to include an assessment guide, verbal descriptors, morphed images, and real subject images for each scale grade. The clinical significance of a 1-point score difference was evaluated in a review of multiple image pairs representing varying differences in severity. Interrater and intrarater reliability was evaluated in a live-subject rating validation study (N = 297) completed during 2 sessions occurring 3 weeks apart.RESULTSA difference of ≥1 point on the scale was shown to reflect a clinically significant difference (mean [95% confidence interval] absolute score difference, 1.22 [1.09–1.35] for clinically different image pairs and 0.57 [0.42–0.72] for not clinically different pairs). Intrarater agreement between the 2 live-subject rating validation sessions was substantial (mean weighted kappa = 0.78). Interrater agreement was substantial during the second rating session (0.73, primary end point).CONCLUSIONThe Allergan Transverse Neck Lines Scale is a validated and reliable scale for rating of severity of neck lines.