Surface Evaluation of Living Skin (SELS) parameter correlation analysis using data taken from astronauts working under extreme conditions of microgravity

Background: In space, due to fluid shift a 45% decrease in the skin topography parameter volume (mm³ ) was seen using the VisioScan^® camera. Simultaneously, the parameters roughness, scaling and wrinkles changed dramatically as well. Thus, the present study has the objective to understand the relationship between the SELS parameters under extreme conditions and their application by addressing scientific-dermatological questions.

Material and methods: SELS measurements were performed on the volar forearms of six astronauts. The Pearson correlation coefficient was used to determine the association between the variables.

Results: A significant correlation was found between the skin topography parameter volume and the skin parameters roughness, scaling and wrinkles. A closer look at each astronaut revealed a significant correlation for all astronauts for the parameters volume and roughness and for more than 65% of the astronauts for the parameters volume and scaling and volume and wrinkles. However, no correlation could be found between the parameters skin hydration and roughness and scaling, respectively.

Conclusion: Only the parameter skin volume leads to meaningful data under microgravity. Physiological changes observed by fluid shift are comparable to the skin condition edema on earth. Based on the obtained data, we can conclude that the formulas for the SELS parameters roughness, scaling and wrinkles for this special skin condition need to be reviewed.