Early versus delayed bilateral subthalamic deep brain stimulation for Parkinson’s disease: A decision analysis.
Espay AJ, Vaughan JE, Marras C, Fowler R, Eckman MH. Early versus delayed bilateral subthalamic deep brain stimulation for Parkinson’s disease: A decision analysis. , 2010 May 21. [Epub ahead of print]
The purpose of this article was to look at the utility of a statistical model to predict the effectiveness of DBS-STN on motor functioning, cognitive abilities, and quality of life when the surgical intervention is done early or later in the disease course. The typical reasoning behind eligibility requirements for people with Parkinson’s disease (PWP) to undergo DBS-STN either early or later is based on length of time that the individual has had Parkinson’s disease (PD) as well as their responses to medicinal intervention (e.g. levodopa medications). Typically, DBS-STN has been used as a therapeutic option later in the disease course (average 14 years) once multiple medicinal treatments have been tried and the PWP often have more motoric disability. These authors suggest that there may be better effectiveness and less disability if PWP undergo DBS-STN earlier in the disease course. They created a statistical model based on the available literature on DBS-STN, a group of PWP that had undergone DBS-STN, and a group of PWP that had not undergone DBS-STN. Their model suggested that early intervention was effective most of the time. They also found that early intervention would have greater effect on quality of life for those who had DBS-STN and that those who had not undergone the surgery preferred the delayed intervention. It was suggested that the discrepancy between the two groups regarding when to have the surgery may have to do with the uncertainty that the non DBS-STN group may have about the risks and complications about the surgery while the DBS-STN group may be more focused on the benefits that they have experienced. The model also indicated that for those PWP whom had a fast progressing motor decline a delayed surgery would be more effective as it was possible that the underlying cause of the decline was mixed and not purely PD. This study was also very upfront about the limitations of using such a model and suggested that clinical trials would be the best way to determine actual effectiveness of early versus delayed surgical intervention. They noted that there are two such trials in process that have looked directly at the question of effectiveness of the early surgical intervention. We at DBS-STN.org are very interested as well in the results of these clinical trials and will review those studies when they are available, so stay tuned for the update!