QOL increases of between 6 and 18% resulted in incremental C/E
ratios not usually considered cost effective (100,000/QALY). Conclusions: The results suggest that DBS may be cost
effective in treating PD if QOL improves 18% or more compared with those receiving best medical management. This
underscores the need for randomized, controlled, prospective DBS experiments including QOL and economic components.