Facial-motion analysis with a video and computer system: a preliminary report

To investigate the feasibility of a video and computer-assisted system for evaluating the temporal and spatial aspects of facial motion during selected facial expressions in a pilot group of six normal adults. Evaluation of the diverse medical and surgical treatments for facial paralysis and paresis cannot occur until objective, reliable, and sensitive measures of the spatial and temporal aspects of facial function at specific facial landmarks are developed.

Facial motion at predetermined facial locations was assessed using a commercially available computer-interactive motion analysis system, which is based on videography principles. The displacement, velocity, and acceleration data were averaged across all trials and subjects. Time plots also were obtained for the left versus right side.

The greatest mean maximum displacement (resultant vector) occurred during the eyebrow lift expression, reaching 1.2 cm in magnitude. The mean maximum velocity (resultant vector), which ranged from 4.5 to 8.5 cm/s for the dynamic facial expressions, was greatest for the eyes closed tight expression. The mean maximum acceleration (resultant vector), which ranged from 193 to 465 cm/s/s, was greatest for the eyebrow lift expression. Symmetrical time plots were obtained. The system documented synkinesis by revealing substantial left upper eyelid motion during the nose-wrinkle expression in an illustrative case with slight left facial dysfunction.

This approach to facial motion analysis is feasible for the simultaneous, multiregional, spatial-temporal assessment of facial expressions. Because motion at relatively remote regions could be quantified, this approach is potentially useful for the evaluation of synkinesis.