title: The effect of age and sex on facial mimicry: a three-dimensional study in healthy adults.
abstract: To assess sex- and age-related characteristics in standardized facial movements, 40 healthy adults (20 men, 20 women; aged 20-50 years) performed seven standardized facial movements (maximum smile; free smile; "surprise" with closed mouth; "surprise" with open mouth; eye closure; right- and left-side eye closures). The three-dimensional coordinates of 21 soft tissue facial landmarks were recorded by a motion analyser, their movements computed, and asymmetry indices calculated. Within each movement, total facial mobility was independent from sex and age (analysis of variance, p>0.05). Asymmetry indices of the eyes and mouth were similar in both sexes (p>0.05). Age significantly influenced eye and mouth asymmetries of the right-side eye closure, and eye asymmetry of the surprise movement. On average, the asymmetry indices of the symmetric movements were always lower than 8%, and most did not deviate from the expected value of 0 (Student's t). Larger asymmetries were found for the asymmetric eye closures (eyes, up to 50%, p<0.05; mouth, up to 30%, p<0.05 only in the 20-30-year-old subjects). In conclusion, sex and age had a limited influence on total facial motion and asymmetry in normal adult men and women.
authors.affiliation: Functional Anatomy Research Center, Laboratorio di Anatomia Funzionale dell'Apparato Stomatognatico, Dipartimento di Morfologia Umana e Scienze Biomediche Città Studi, Facoltà di Medicina e Chirurgia, Università degli Studi di Milano, via Mangiagalli 31, Milan, Italy. chiarella.sforza@unimi.it
authors.forename: C
authors.initials: C
authors.lastname: Sforza
authors.forename: A
authors.initials: A
authors.lastname: Mapelli
authors.forename: D
authors.initials: D
authors.lastname: Galante
authors.forename: S
authors.initials: S
authors.lastname: Moriconi
authors.forename: T M
authors.initials: TM
authors.lastname: Ibba
authors.forename: L
authors.initials: L
authors.lastname: Ferraro
authors.forename: V F
authors.initials: VF
authors.lastname: Ferrario
mesh_terms: D000328:Adult; D000367:Age Factors; D001767:Blinking / Q000502:physiology; D002680:Chin / Q000033:anatomy & histology / Q000502:physiology; D005143:Eyelids / Q000033:anatomy & histology / Q000502:physiology; D005145:Face / Q000033:anatomy & histology*; D005146:Facial Asymmetry / Q000473:pathology / Q000503:physiopathology; D005149:Facial Expression; D005152:Facial Muscles / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D005546:Forehead / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008046:Lip / Q000033:anatomy & histology / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009055:Mouth / Q000033:anatomy & histology / Q000502:physiology; D009119:Muscle Contraction / Q000502:physiology; D009666:Nose / Q000033:anatomy & histology / Q000502:physiology; D012737:Sex Factors; D012904:Smiling / Q000502:physiology; D014741:Video Recording; D055815:Young Adult