So far, everyone who has responded to you here that the Neuropsychological exam has benefit, has been 100% correct. I consulted with two experts in the field and they explained the benefits far outweigh any reasons to avoid the testing. Diagnosis tools have come a long way since I dealt with this subject with my mom, and you would be wise to take advantage of this. It will help also with long term planning. Again, give her an incentive and tell her you will take her out for a lovely lunch afterwards!