Jim,
Are there any other neurological options other than the MSU department? If they're not responding, I think it behooves you to find someone in that area of expertise.
Or else, go there first thing monday morning and speak to them face to face, with Allison. Failure to even call back is ridiculous. The only other thing I can think of is speaking to the doctors who have already seen her and seeing if they can get a response from the MSU department (assuming they just told you to make the appointment instead of making the referral).
Good luck and godspeed. I'll be thinking of you both.