Stimulation of the subthalamic nucleus in Parkinson’s disease: a 5 year follow up
Schupbach, W. et al Stimulation of the subthalamic nucleus in Parkinson’s disease: a 5 year follow up , 2005 Dec;76(12):1640-4
This article discusses the results of 37 patients with PD that underwent bilateral DBS-STN at a clinic in France. Patients were evaluated at 1 month prior to surgery and 6, 24, and 60 months after surgery. They had strict criteria for inclusion of patients for surgery and had attrition of 6 patients by the end of the study (5 deaths, 1 relocated). They found that the patients had more motor improvement with stimulation and levodopa combined versus either treatment alone. They also found less dyskinesias and less need for levodopa, but that the benefit decreased across time. Patients also had improvement in their activities of daily living at the 6 month point, which was lost at the later testing times.
Scores on depression and cognitive screening remained the same across testing through 24 months, but performance on a cognitive screening measure began to worsen at the 60 month evaluation. Their patients did not experience permanent adverse events during the 5 year trial but had various transient events (e.g. emotional fluctuations, urinary retention, eyelid opening difficulties, weight gain). A total of 13 stimulators had to be replaced in the group of patients due to low power (anticipated or experienced) in the battery. The authors listed multiple side effects of intermittent stimulation due to the battery. One of the limitations of this article was that there was no control group of patients with PD to compare to those who underwent DBS-STN. The authors suggest that regardless of a control group there was sustained improvement five years after DBS-STN. They also suggested the possibility of neuroprotective factors of DBS-STN but noted the literature is mixed and mostly completed on animal models. They concluded by suggesting more long term studies to measure the efficacy and possible protective factors of DBS-STN.