Diagnosis system for the quantitative assessment of facial nerve palsy based on the image analysis of facial movements

Facial expression is very complicated and delicate, that is due to a mutual link among facial muscles under control of facial nerves. Generally, a front view of facial movement is symmetrical on right and left in healthy condition, however, it shows asymmetry in case that the neuromuscular system is injured or disordered by the so-called facial paralysis or facial nerve palsy. In clinical diagnosis of the facial nerve palsy, quantitative and objective assessment of the facial movement is strongly required at present. In this study, a diagnosis system for the quantitative assessment of facial nerve palsy has been proposed using the optical flow method that presents the degree of precise movements in the facial area. Sequences of facial images have been analyzed to depict the optical flow for various kinds of facial expression. Right-left ratio of the facial movements obtained from the optical flow is very effective for the quantitative assessment of facial nerve palsy and it is available to the clinical use.