Dynamic Title with field Parameters

Hi,

So I have created field parameters and a slicer to put into a matrix. Now I tried to use a dynamic heading for these parameters, so it always shows the selection of the measures. 

I used this DAX: 
"Comparison of values " & CONCATENATEX(
VALUES(Fluctuation[Selection_Measure Fields]),
Fluctuation[Selection_Measure Fields],
", "
)

But the result of the title is is as follows:

In my Measure selection the names I have given the measures in the parameters are shown:

How can I use those in my title? 

Thank you for any help!