Quick Question on glmer.nb

Hi folks,
 
I was working with glmer.nb function to estimate a negative binomial mixed effects model.
I was wondering if there is any chance to get the t statistics or the p values for the random effects as well as the fixed effects? 

Thank you so much for your time.

Sincerely, 
Pasha

P.S. More info just in case my question is not clear:
I am looking to find a way to justify if I should assume a random slope for a variable or not. The lme4 output shows the standard deviation of each random parameter, but it does not say anything about its significance for the model (Please correct me if I am wrong).