Estimating Brain Health from Facial Expressions: An Exploratory Study

In recent years, increasing attention has been paid to the effects of reading and art on the human brain. However, how these activities are associated with brain structure in healthy middle-aged adults remains unclear, partly because structural brain measures are not easily accessible outside MRI-based settings. In Study I, we analyzed the correspondence between gray matter volume (GMV) derived from brain MRI and facial-expression data obtained while participants imitated four facial expressions (happiness, anger, sadness, and surprise). Based on these data, we developed an exploratory algorithm and a digital application to estimate brain-health-related indices from facial expressions. In Study II, we examined correlations between the estimated brain-health-related indices and questionnaire-based measures of creative behavior and reading habits in 113 self-reported healthy middle-aged adults. The results showed that estimated indices related to the default mode network (DMN) and central executive network (CEN) were positively associated with creative behavior and reading habits, respectively. To our knowledge, this is among the first studies to explore whether facial-expression-based estimates of brain-health-related indices may be used to examine associations between everyday intellectual activities and brain-health-related characteristics. However, the findings should be interpreted cautiously because the estimation model was evaluated within a limited sample, included repeated observations, and has not yet been externally validated.