Evaluación del efecto de la estimulación cerebral profunda del núcleo subtalámico sobre el equilibrio en pacientes con enfermedad de Parkinson mediante análisis posturográfico

Abstract

The effect of deep brain stimulation of the subthalamic nucleus (STN-DBS) on postural instability in Parkinson’s disease (PD) is debated. Methods. We evaluated 16 PD patients with STN-DBS and 13 controls by posturography. Patients were evaluated under four conditions: no medication or stimulation: only stimulation: only medication: with medication and stimulation. We assessed 20 paradigms using 21 posturographic parameters. The Mann-Whitney test and Receiver operating characteristic (ROC) curve analysis were used to compare patients with controls. The Wilcoxon test was performed to evaluate patients under different conditions. Results. The best paradigm for differentiating patients from controls was performing a cognitive task. STN-DBS improved balance when patients were standing upright with their eyes open and closed, performing a ballistic movement and performing the pull test. Medication improved balance when patients were performing a cognitive dual task, standing upright with eyes closed, and getting up from a chair. STN-DBS combined with medication had a deleterious effect on dynamic balance when patients were stepping down, twisting, performing the pull test, and standing on one leg. Conclusions. STN-DBS could improve certain aspects of postural control when a patient is standing upright with eyes open or closed and after a sudden perturbation of balance. Balance could be better when performing a cognitive task, standing up from a chair and standing with eyes closed under medication effects. However, the synergistic effect of STN-DBS and medication could lead to impairment of balance, especially under dynamic conditions. The negative synergistic effect of both therapies could be due to the adverse effects of levodopa on cognition, the lack of effect of current stimulation parameters on the axial symptoms of PD, or an eventually negative effect of STN-DBS on the pedunculopontine nucleus. These findings highlight the impairment of balance in PD patients in cognitively demanding situations.