Progression and survival in Parkinson's disease with subthalamic nucleus stimulation

BackgroundTreatment for Parkinson's disease (PD) is symptomatic. Surgical treatment with continuous high-frequency stimulation of the subthalamic nucleus (STN-DBS) is established as a safe symptomatic treatment with long-term beneficial effects. It has been postulated that STN-DBS could halt the progression of PD through a disease modifying or neuroprotective effect. ObjectiveTo investigate the postulated disease modifying or neuroprotective effect of STN-DBS by comparing the rate of deterioration of parkinsonism and mortality over time in two selected and matched groups of patients with PD with and without surgery. MethodsGroup A was derived from all patients who received STN-DSB surgery at Oslo University Hospital, from January 2001 to December 2007. Group B was derived from a prevalence study of PD in the Stavanger area of Western Norway in 1993. The two groups were individually matched and the disease progression measured by Unified Parkinson's Disease Rating Scale-motor scores, and the mortality was compared. ResultsThe mean annual change based on baseline and last observation scores in individually matched groups was 0.97 (SD=3.57) for the surgery group and 1.04 (SD=3.33) for the controls and thus not significantly different, F(1, 104)=.21, P=0.89. The long-term mortality was also similar in the two groups during long-term follow-up, hazard ratio=1.76, CL 0.91-3.40, P=0.091. ConclusionThis study gives no support to a postulated disease modifying or neuroprotective effect of STN-DBS in patients with PD.