Five-year follow-up of 23 asymmetrical Parkinson's disease patients treated with unilateral subthalamic nucleus stimulation

Abstract

In this study, 23 asymmetrical Parkinson's disease patients were treated with unilateral deep brain stimulation of the subthalamic nucleus and followed up for 5 years. At 5 years after stimulation treatment, Unified Parkinson's Disease Rating Scale II, III and axial symptom scores in the off-drug condition were significantly increased compared those at baseline. However, total Unified Parkinson's Disease Rating Scale II, III and axial symptom scores were significantly lower with stimulation-on compared with the synchronous stimulation-off state in off-drug condition, and the motor symptoms of contralateral side limbs were effectively controlled. Only low Hoehn-Yahr stage was correlated with good long-term postoperative improvement in motor symptoms. The mean levodopa-equivalent daily dose after stimulation treatment was significantly lower than that before treatment, but dyskinesias became worse. Our experimental findings indicate that unilateral deep brain stimulation of the subthalamic nucleus is an effective treatment for improving motor symptoms in well selected asymmetrical Parkinson's disease patients presenting no severe axial symptoms and dyskinesias.

Keywords: Parkinson's disease; deep brain stimulation; neural regeneration; subthalamic nucleus.

Figure 1

Improvements in Unified Parkinson's Disease Rating Scale (UPDRS) II & III scores at 1 and 5 years postoperatively analyzed by left- and right-side procedures. Although right-side procedures always produced greater improvements in symptoms than left-side procedures, no significant difference was found between them with Student's t-test (P = 0.207, 0.143, 0.172, 0.208 respectively). Data are expressed as mean ± SD. The improvement calculation was compared with baseline .

Figure 2

Improvements in Unified Parkinson's Disease Rating Scale (UPDRS) II & III scores at 1 and 5 years analyzed by Hoehn and Yahr (H&Y) stages. In summary, lower H&Y stage was associated with greater improvements in UPDRS II and III scores (^aP < 0.05, vs. H&Y stage ≥ 3). A least significant difference t-test analysis of stages ≤ 2, 2.5 and 3 showed that the improvement of UPDRS III was significantly different between stage ≤ 2 and stage ≥ 3 at 5 years (P = 0.014). Data are expressed as mean ± SD. A significant difference in the degree of improvement in UPDRS II scores was also found between patients in stage 2.5 and those in stage ≥ 3 (P = 0.036) at 5 years postoperation. The improvement calculation was compared with baseline .