The posts from Bart and myrgirl are right-on. I frequently travel with my retarded/epileptic/physically rickety sister who gets skycap assistance. One way I've gotten it is by asking for a wheelchair. They put it in her record.
In every airport and airline I"ve used she has always been treated with great care and respect. Furthermore, the TSAs have been extremely kind as well, even when we've had to have secondary screening... which is pretty much the norm.
I am able to step away from her to walk through the regular equipment, but they have always asked me whether Chrissy could be alone, or if she would feel more comfortable if I stay right with her.
Your challenge is a bit different, but I'm sure you'll find people responsive to your needs.
Rita