Objective assessment of the severity of unilateral facial palsy using OKAO Vision® facial image analysis software.
CONCLUSIONS
Severity of ipsilateral facial palsy (UFP) can be assessed objectively by use of OKAO Vision®. Facial symmetry percentage (FSP) values were well correlated with the results by two conventional grading systems.


OBJECTIVE
To introduce the basic principle of facial motion analysis using OKAO Vision®, to represent the data measured in patients with UFP, and to show the correlation between the severity of facial palsy assessed by this method and conventional systems.


METHODS
Two independent facial motions, closing the eyes and grinning, were recorded with a video camera. By comparing the movement distances between right and left sides, the eye symmetry ratio (ESR) and grin symmetry ratio (GSR) were obtained. The degree of UFP was assessed by FSP, which was calculated by the formula: FSP = (ESR + GSR)/2 × 100 (%). FSP was measured in 12 normal volunteers and in 30 patients with UFP.


RESULTS
In patients with UFP, varying degrees of FSP were noted corresponding to the grade of facial palsy. The severity of facial palsy assessed by FSP was closely correlated with the Yanagihara score (r = 0.88, p < 0.05) and was inversely related to the House-Brackmann grade (r = -0.90, p < 0.05).
Department of Otolaryngology Head and Neck Surgery, Ehime University School of Medicine, Ehime, Japan.
Naoki
N
Sawai
Naohito
N
Hato
Nobuhiro
N
Hakuba
Hirotaka
H
Takahashi
Masahiro
M
Okada
Kiyofumi
K
Gyo
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003936:Diagnosis, Computer-Assisted; D005146:Facial Asymmetry / Q000145:classification / Q000175:diagnosis; D005149:Facial Expression; D005158:Facial Paralysis / Q000145:classification / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012984:Software