Characteristics of the perception for unilateral facial nerve palsy

Patients with facial nerve palsy (FNP) are actually evaluated by other people rather than doctors or the patients themselves. This study was performed to investigate the characteristics of the perception of unilateral FNP in Korean people. A questionnaire using photographs of four patients with four different grades (House-Brackmann) of FNP was given to two hundred people with no FNP. Subjects of each gender, ranging from 20 to 69 years of age, participated. The questionnaire, showing facial expressions of resting, smiling, whistling, eye closing, and frowning, consisted of questions concerning the identification and the involved side of FNP, the unnatural areas of the face, and the unnaturalness of the facial expressions. The overall identification rate of FNP was 75.0%. The identification rate increased according to the increase in the grade of the patient's FNP (p < .001). The overall detection rate of the involved side was 54.5%, and that rate decreased with increasing subject age (p < .001). The area of the most unnatural facial expression was reported to be the mouth, followed by the eyes and cheeks. The most unnatural facial expression was also reported to be smiling, followed by eye closing and whistling. There was no difference in the identification rate of FNP according to education level. However, the overall detection rate of the involved side was higher in the high-education group (p < .001). The detection rate for the involved side of FNP was lower than the rate of identification of FNP and was significantly low in the middle-aged/elderly and low-education level groups.