Human Face Mapping Based on TEWL, Hydration and Ultrasound

Biophysical properties of the skin vary depending on the skin location. Such properties include skin structure, density of skin layers, pH, temperature, hydration and Transepidermal Water Loss (TEWL).Modern technologies and quantitative methods allow reading and analysing the skin properties using in-vivo based analysis. One goal of such analysis is partitioning the skin in areas with similar properties, which is referred as mapping. The purpose of our study, also the novelty of the project, is mapping of the facial skin in terms of TEWL, hydration and skin layer thickness, as well as measuring the effect of physical exercise on facial skin; where possible, effect of sex and age were also considered. TEWL was measured with AquaFlux, skin layer thickness was measured with Episcan high resolution ultrasound imaging, and skin hydration was measured with Epsilon. Our study reveals material difference of TEWL between the facial sites being analysed; the largest differences were noted between the lips and the neck. It was found that skin hydration levels decrease with the advancement of age. Skin hydration readings reveal larger general effect of exercise for females, and strongest effect for males observed on the nose. Skin ultrasound images were used in two ways. First, face was mapped in terms of the thickness of the individual skin layers and such mapping was found to be different for each layer. Secondly, the differences between the sites in terms of thickness were quantified using Welch test, where age was also found to be a factor. Several Machine Learning-based classifiers of the skin location were also trained, which are based on the cross-sectional image with moderate positive outcome. The study showed that the combination of TEWL, Epsilon and Episcan provides useful information about skin health. The study also showed variations in the values for different facial skin sites of several skin samples, which was likely due to the degree of corneocyte formation, the lipid contents of the Stratum Corneum (SC), skin temperature, damaged barrier function, bodily health and skin blood flow.