To test the reliability of a simple rating system to describe hyperkinetic facial lines.Methods
A rated numeric kinetic line scale was developed and presented to 11 postresidency physicians specializing in aesthetic facial care. These physicians independently reviewed photographs of 20 patients, first at rest, then with activation of the frontalis, corrugator, and orbicularis oculi muscles. Kappa statistics for multiple raters were used to assess interobserver reliability.Results
The nonweighted κ values were between 0.4 and 0.8 for the frontalis, corrugator, and orbicularis muscle groups. This represents moderate to substantial observer agreement and is highly significant for each muscle group.Conclusions
A new rating scale for hyperkinetic facial lines accounts for facial appearance at rest and with expression. It is easily used and has interobserver reliability. As the only objective and validated scale for hyperkinetic facial lines, this rated numeric kinetic line scale is recommended for the evaluation of pretreatment and posttreatment results in patients undergoing therapy for this problem. Moreover, an alternative scale rating resting and kinetic lines as independent variables is also being developed. Both must be considered to evaluate treatment outcomes when using neurotoxins.