My daughter is eight years old, but due to her cerebral palsy, she has the approximate mentality of a three year-old. She also has an extreme need for routine. Most of the time that isn't an issue at all, as our family has a routine anyway. Other times, it's a minor issue, such as one parent doing a certain part of the routine that the other parent usually does. That happens often enough that she complains a little, but deals with it.
Sometimes she gets fixated on something we can't or shouldn't provide, and no amount of distracting her with other favorite activities will change her mind. Does anyone have ideas for putting a one track mind on a different track? I imagine parents of autistic children have had similar challenges, but even successful tactics from parents of neurotypical but stubborn children would be useful.