Help with DAX

Hello colleagues, I have to create a DAX to calculate something, but I don't know what measure to do. I have two periods (see table) which are "Jan 2017-Dec 2018" and "Jan 2019 - Feb 2020" (in Spanish). I need to calculate the difference between the values of those two associated periods, for example, for the aspect "Tools clarity" (or "Claridad de las herramientas" in Spanish"), to see its evolution (increase or fall); for the case of that particular aspect, the difference would be -0.08 (9.62 - 9.70), I want to calculate that difference, for all the evaluated aspects, using only one DAX measure. Thank you very much.