true....but there is a study out that suggests that DBS MAY stop progression!!
"Conclusions/Relevance: Our data show that untreated PD motor scores do not worsen over time in patients undergoing STN DBS, suggesting that there is no progression of disease severity. These results could be explained either by a ‘natural’ stabilization of PD progression after many years or neuroprotective properties of STN DBS. However, possible study design artifacts, including insufficient stimulation washout times, could have affected these data."


http://www.parkinsonalliance.org/research.php?ID=286


Charlie