Subthalamic nucleus-deep brain stimulation for early motor complications in Parkinson's disease-the EARLYSTIM trial: early is not always better.

Subthalamic nucleus deep brain stimulation (STN-DBS) has revolutionized the management of disabling motor complications in Parkinson's disease. The EARLYSTIM trial applied this treatment to patients who had been experiencing motor complications for less than three years. STN-DBS significantly improved all primary and secondary outcome measures while best medical therapy failed to provide any improvement at the two-year follow-up time point. On face value these results strongly favor the application of STN-DBS far earlier than is currently applied, when patients are just beginning to experience problems with motor complications. Here we review the application of early DBS and the EARLYSTIM trial from the perspectives of clinical issues, health economics and study design and patient expectation of benefit. We conclude that the most relevant issue is not when to operate but on whom and that early is not always better.