Three-dimensional quantification of "still" points during normal facial movement

This study investigated the 3-dimensional displacement of points on the fac e that were thought to be still during facial movement. These points are cu rrently used to measure displacement of moving facial regions during assess ment of normal facial movement and treatment interventions following facial nerve paralysis. It is, however, unknown if these places are "still" point s. The Expert Vision Motion Analysis System was used to collect and analyze data on 42 normal subjects during facial movement. No point on the face wa s found to be still during facial expression. However, several points were present with very small movements for each individual expression. These wer e termed "reference" points. These small movements may be the result of sys tem noise, physiological tremor, skin movement, or head-holder movement dur ing facial expressions. Future studies of the displacement of the markers d uring facial movement in both normal subjects and patients with facial nerv e paralysis may take into account the contribution of the "reference" point displacements to the overall facial movement.