The evaluation of facial palsy by amount of feature point movements at facial expressions.

At present, in the medical field 40-point method and facial nerve grading system are generally used for evaluation of facial palsy. However, these methods have limitation in the precise evaluation, because of subjectivity in diagnosis. Purpose of This work is to propose quantitative evaluation of facial palsy based on the amount of movements of the feature point on the face. Facial nerve symptoms generally appear in either side of the face. In facial expression movement, the motion in the palsy side becomes smaller than that of the healthy side. We defined some indices of palsy grade obtained by the observation of the facial motion. Those indices showed the asymmetry of the facial motion quantitatively. We confirmed that our proposed method is valid for estimation of facial palsy from comparison with 40 points method.