Validation of the objective assessment of facial movement with a new software-based system

Background: Most used subjective Unilateral Peripheral Facial Palsy (UPFP) grading systems are characterized by high variability and low reproducibility and doesn’t allow a separate evaluation of single facial regions. Objective: To assess the reliability of a new objective method for classification of UPFP, comparing it with House-Brackmann (HB) and Sunnybrook facial grading (SFGS) systems. Method: Forty-seven patients affected by UPFP of different HB grade were included. Each patient underwent a blinded examination by three different operators, via the two subjective methods (HBGS and SFGS) and a newly proposed objective one, that was obtained from a digital video-analysis, named SMART FACIAL system. Results were converted by validated conversion scales into HBGS grades and statistically compared. Results: In 87,23% (n° 41 pts) consistency was found between the grades obtained with all the three evaluation methods; in 10,41% (n°5 pts), between HBGS and SFGS grade and in 2,08% (n°1 pt) between HBGS grades and SMART-FACIAL system. Statistical analysis showed significant correlation among the three systems (p<0,000). Conclusions: The SMART FACIAL system presents high reliability also in comparison with the most frequently used subjective methods. Significance: This method represents a fast, simple and thorough way to analyze UPFP, especially during physical rehabilitation.