Comparing GPi vs STN deep brain stimulation for advanced Parkinson disease
Is GPi or the STN is the optimal target for Deep Brain Stimulation (DBS) for Parkinson Disease (PD)? 3-year follow-up results reported from the Netherlands NSTAPS prospective controlled trial show STN DBS provides more off-phase motor improvement, with a similar risk for cognitive, mood, and behavioral complications. 128 advanced PD patients were enrolled and randomized (90 completed the 3-year follow-up) showing STN DBS superiority: more motor improvement (STN 28 [20-36], GPi 33 [23-41], p = 0.04); larger improvement in off-drug functioning (STN 72.6 ± 18.0, GPi 65.2 ± 20.1, p = 0.05); more levodopa equivalent dose reduction (STN 605 [411-875], GPi 1,060 [657-1,860] p < 0.001); more re-operations after GPi DBS. No composite score difference was observed for cognition, mood, and behavior, and the inability to participate in follow-up. In contrast, the previously reported 3-year VA Cooperative trial showed comparable motor benefits for both targets, but with an increased STN DBS dementia risk. However, it is difficult to compare the results of the two studies due to methodological differences. The reasons for the lack of comparable improvements to other trials in the GPi group in the NSTAPS trial are unclear. Therefore, STN vs. GPi target for effective and cognitively safe PD DBS is unresolved.