Which target for DBS in Parkinson's disease? Subthalamic nucleus versus globus pallidus internus

Abstract

We selected 14 patients with advanced idiopathic Parkinson's disease (PD) and examined the clinical effects of STN DBS versus GPi DBS. Nine patients underwent bilateral STN DBS and five underwent bilateral GPi patients. All patients were followed for at least 12 months. The evaluation was performed on and off drug before surgery; on-drug/on-DBS and off-drug/on-DBS at 1, 3, 6 and 12 months after stereotactic surgery. At 1 and 3 months after surgery in off-drug/on-DBS condition, both groups showed an improvement in motor score (UPDRS III). Nevertheless, the results changed after long-term stimulation in the two groups. Chronic STN DBS is superior to GPi DBS in the amelioration of the clinical features and in the decrease of time spent in the off state. The efficacy in reduction of LID was comparable at 1 and 3 months after surgery, but the results were better in STN DBS after chronic stimulation. The L-dopa dose was reduced only in the STN group.

Surgical Management of Parkinson's Disease: Update and Review

“…As such, it is difficult to compare the results from the two sites. These results and those of other studies of stimulations of the subthalamic nucleus have been consistently robust with most studies showing 45-55% improvement and some showing as high as 60-70% improvement in "off" medicine motor subscore 57,58,[60][61][62][80][81][82] . Study of 42 patients followed up for five years showed that improvement seems to be stable with continued efficacy and a 54% improvement in "off" motor score 80 .…”

“…The results of one study of the bilateral globus pallidus DBS in 11 patients followed up for up to five years showed that dyskinesias remained significantly reduced until the last assessment, but initial improvement of "off"-period motor symptoms and fluctuations was not sustained and gradually declined 59 . Whether or not this study is representative of the long-term effect of DBS of the internal globus pallidus requires further study in more patients.In contrast to thalamotomy or Vim DBS, GPi DBS has reliably alleviated all cardinal motor symptoms of Parkinson's disease including akinesia, brandkinesia, rigidity, tremor and gait 39,57,58,[60][61][62][63][64][65][66][67] . DBS of GPi improves "off" dystonia 68,69 and, like pallidotomy, has a strong, direct, suppressing effect on levodopainduced dyskinesias 39,58,65,[70][71][72] .…”

Deep brain stimulation in Parkinson’s disease

“…Only a few studies have tried to directly compare GPi and STN DBS [32][33][34][35][36]. However, most of these studies were not randomized and they had relatively small sample sizes.…”

“…Improvement in UPDRS motor scores was greater in the STN group (67%) compared with the GPi group (54%). Scotto di Luzio et al [35] compared nine patients with STN DBS to five patients with GPi DBS. STN DBS was demonstrated to be superior to GPI DBS both in the control of clinical features and the reduction in off time.…”

Delayed and lasting effects of deep brain stimulation on locomotion in Parkinson's disease

“…4 The choice of stimulation target has evolved since and studies have reported positive effects of DBS on locomotion and postural stability, following stimulation of the STN, [24][25][26][27]2,14,28 SNr, 29 cortex, 30,31 thalamic Vim, 32 and zona incerta, 33 to name but a few. Today, multiple stimulations ͑e.g., STN + PPN͒ are emerging as a possibility to alleviate distal as well as axial signs.…”