Decision under risk: Argument against early deep brain stimulation in Parkinson's disease.

Deep brain stimulation (DBS) typically has been delayed until late stage of Parkinson's disease (PD), a mean of 14-15 years after diagnosis. EARLYSTIM study applied DBS in patients with PD presenting motor complications for less than three years, and showed that early stimulation offered greater benefit than best medical therapy in all primary and major secondary end points. Based on the results of EARLYSTIM study, the U.S. Food and Drug Administration recently approved DBS for use in people with PD of at least four years duration and with recent onset of motor complications. However, despite of more benefit from DBS surgery than best medical therapy in early stage of PD, we need to consider the risks of surgery and human nature of risk aversion. Here, we make arguments against early DBS stimulation based on the prospect theory.