Measuring facial paralysis using the three-dimensional dynamic quantitative analysis system of facial motion: correlation with subjective grading systems

Abstract

The aim of this study was to measure the facial motion of patients with facial paralysis using a three-dimensional dynamic quantitative analysis system of facial motion (3D ASFM) and analyze its correlation with subjective grading systems. We included 30 healthy volunteers and 50 patients with unilateral facial paralysis. After placing landmarks on the faces, the facial motions of the patients were measured using the 3D ASFM. The regional symmetry ratios(SRs) and gross scores of different parameters were calculated. Then a comparison with four subjective grading systems(House-Brackmann, Sunnybrook, Facial Nerve Grading System 2.0, Fisch) was performed. The entire test could be completed within five minutes. The normal range of healthy volunteers were obtained, the gross score of which was 91.9±1.5. The SRs of the maximal moving distance(MMD) were most strongly correlated with regional subjective grading systems, followed by the SRs of the maximal moving velocity (MMV). The SRs of the maximal moving acceleration (MMA) were either poorly correlated or uncorrelated with the subjective grading systems. Moreover, the Spearman coefficients with four subjective grading systems were -0.630(House-Brackmann), -0.728(Facial Nerve Grading System 2.0), 0.697(Sunnybrook), and 0.617(Fisch)respectively(P<0.05). The 3D ASFM is a convenient method to rapidly assess facial paralysis. It not only overcomes the shortcomings of conventional subjective grading systems, but also correlates well with them.