Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology
STN-SNr co-stimulation in Parkinson's disease: a systematic review and meta-analysis of motor and freezing-of-gait outcomes
By Kong L, Li P, Bi Y and 4 others.
Abstract
Background
Freezing of gait (FoG) and axial impairments often persist in Parkinson's disease despite optimized medication and subthalamic nucleus deep brain stimulation (STN-DBS). We systematically reviewed whether adding substantia nigra pars reticulata (SNr) stimulation improves motor and FoG outcomes.
Methods
Following PRISMA 2020 and PROSPERO registration (CRD420261343479), six databases were searched through 1 May 2026. Primary outcomes compared STN-SNr co-stimulation with STN-only stimulation; stimulation-off or baseline comparisons were secondary. Two reviewers independently screened studies, extracted data, and assessed risk of bias. UPDRS-III and FoG were pooled as mean differences (MDs) and Hedges' g, respectively, accounting for paired data and within-study dependence. Certainty was assessed using GRADE.