SENSITIVITY OF A METHOD FOR THE ANALYSIS OF FACIAL MOBILITY - I - VECTOR OF DISPLACEMENT

Objective: (1) To determine which facial landmarks show the greatest m ovement during specific facial animations and (2) to determine the sen sitivity of our instrument in using these landmarks to detect putative ly abnormal facial movements. Design: Movements of an array of skin-ba sed landmarks on five healthy human subjects (2 men and 3 women; mean age, 27.6 years; range, 26 to 29 years) were observed during the execu tion of specific facial animations. To investigate the instrument sens itivity, we analyzed facial movements during maximal smile animations in six patients with different types of functional problems. In parall el, a panel was asked to view video recordings of the patients and to rate the degree of motor impairment, Comparisons were made between the panel scores and those of the measurement instrument. Results: Specif ic regions of the face display movement that is representative of spec ific animations. During the smile animation, landmarks on the mid- and lower facial regions demonstrated the greatest movement, A similar pa ttern of movement was seen during the cheek puff animation, except tha t the infraorbital and chin regions demonstrated minimal movement. For the grimace and eye closure animations, the upper, mid-facial, and up per-lip regions exhibited the greatest movement. During eye opening, t he upper and mid-facial regions, excluding the upper lip and cheek, mo ved the most, and during lip purse, markers on the mid- and lower face demonstrated the most movement, We used the smile-sensitive landmarks to evaluate individuals with functional impairment and found good agr eement between instrument rankings based on the data from these landma rks and the panel rankings. Conclusion: The present method of three-di mensional tracking has the potential to detect and characterize a rang e of clinically significant functional deficits.