What additional treatments do you offer to patients with Progressive Supranuclear Palsy other than a levodopa/carbidopa challenge?

One should be certain to try levodopa at a high enough dose and for a long enough period before considering it a failure. I typically will get to 1200mg levodopa divided into 3 or 4 doses and maintain for at least a month (barring side effects). Pushing higher would not be wrong, but this seems to b...