Date: July 2019.
Source: PLoS ONE 14(7): e0219451.
Abstract: Facial expressions play an important role in the communication of emotions and thoughts. It is no exaggeration to say that the face is an organ of communication. Aging is related to impairment of various motor and cognitive functions. A recent study that examined the perception of emotions found that facial expressions have reduced signal clarity when shown on older faces, especially for smiling . This suggests that aging results in dysfunctional communication.
However, the mechanisms underlying age-related communication dysfunction are incompletely understood. Aging of the face affects facial configurations and their changes during facial expressions. A Moire 3D analysis system determined that facial sagging becomes progressively more noticeable with aging . Three-dimensional analysis of labial morphology showed a significant effect of age on labial thickness and area . A study comparing 3D faces of mothers and daughters found that the greatest atrophy associated with aging was observed in the upper lip, lateral canthi, labial commissures, and gonial angle . When optical images were used to distinguish nasolabial lines, it was found that the lines were significantly increased age-dependently . A study that investigated age effects on the relationship between teeth and facial soft tissue found that the perioral soft tissues dropped down in older subjects and the soft tissue descended along the entire labial arch . Another study found that young people had a larger lip area and thickness than elderly people  . A recent study showed that facial features at rest are more reliable aging biomarkers than blood profiles , in which eye slopes were identified as highly associated with age. These results show that aging affects the facial configuration at rest; however, there remain unanswered questions about the effects of aging on facial configurations during smiling.
In the present study, we focused on female subjects, because the functional decline in facial expression recognizability was considered more important for women under the forthcoming super-aging societies wherein women have a life expectancy at birth 4.7 years longer than that of men, averaged across countries . Further, a meta-analysis showed that women smile more frequently than men do , and this suggests the existence of the interaction of sex effects on functional decline.
Recently, Tanikawa et al.  developed an objective method for evaluating the 3D soft tissue configuration of the face. Using that method, the present study aimed (1) to clarify whether the entire facial surface differs in form between older women and younger women; and (2) to clarify the mechanisms of age-related nonverbal communication dysfunction.
Article: Functional decline in facial expression generation in older women: A cross-sectional study using three-dimensional morphometry
Authors: Chihiro Tanikawa, Sadaki Takata, Ruriko Takano, Haruna Yamanami, Zere Edlira, Kenji Takada
Date: July 2019.