Hi,
I am normally careful with a prognosis especially for neuro cases. Too many things contribute. Roughly I work with period from cva to onset of increased tone. The shorter that is the better the prognosis(i.e. the period in which the patient's tone is floppy. I also check the current rate of recovery, patient cognitive functions (are they able to understand and follow instructions). Also their age and absence of any complicating medical conditions. Here in Zim I have seen HIV & Aids as an underlying medical condition and in the absence of ARVs I have seen cases with relatively "good prognosis" depreciate over time.

Dont have any literature at hand but I hope this helps..