Three-Dimensional quantification of the symmetry of normal facial movement

Objective: This study examined the right to left symmetry of the displacement of three-dimensional movement of the human face. Methods: Displacement data on 42 subjects was collected and analyzed with the Expert Vision Motion Analysis System. Right and left three-dimensional facial displacements were quantified. Results: Significantly greater left than right three-dimensional displacement across the whole face was measured. The three-dimensional displacement difference ranged from 0.48 mm to 2.28 mm between the right and left sides of the face. The 2-cm inferior pupil markers during the nose wrinkle expression had significantly greater left than right displacement. Conclusion: The ranges of displacement differences, along with the mean three-dimensional displacement measures, must be accounted for in the creation of a baseline of the range of normal facial movement.