A review of the effects of spinal cord stimulation on motor symptoms in individuals with Parkinson's disease

• SCS shows promise in alleviating Parkinson's motor symptoms. • Diverse stimulation parameters impact SCS effectiveness in PD. • Studies show improvements in gait and postural stability with SCS. • SCS could benefit patients resistant to levodopa and DBS. • Further research needed to standardize SCS protocols for PD. Parkinson's disease (PD) is a progressive neurodegenerative disorder marked by motor symptoms such as postural instability. While conventional treatments like levodopa and deep brain stimulation (DBS) can be effective in early stages, they often fail to address axial symptoms in advanced PD. Spinal cord stimulation (SCS) has emerged as a potential alternative, targeting the spinal cord to modulate neural activity and improve motor function. This systematic review aims to evaluate the effectiveness of SCS on motor symptoms in PD. This systematic review followed a registered protocol (PROSPERO CRD42021261069) and included studies involving SCS intervention in PD patients. The search was conducted across four electronic databases until December 2023, focusing on terms related to SCS and motor symptoms in PD. Eligible studies included those with SCS applied at any spinal level, irrespective of the intervention duration, and involving outcome variables related to motor symptoms. The review analyzed 21 studies with approximately 70 patients. Stimulation parameters varied widely, including different spinal levels, frequencies, pulse widths, and amplitudes. Most studies reported improvements in motor symptoms, particularly in gait and postural stability. The findings suggest that SCS may offer a promising alternative for managing motor symptoms in PD, especially for those resistant to levodopa and DBS. Despite encouraging results, the variability in outcomes highlights the need for further research to optimize SCS protocols, identify suitable patient profiles, and understand the long-term effects. Larger, well-designed clinical trials are necessary to establish standardized guidelines for using SCS in PD treatment.