Low-Frequency STN-DBS for Standing and Gait Initiation in Parkinson’s Disease: A Double-Blinded Randomised Cross-Over Feasibility Trial

BACKGROUND: Following high-frequency (>100 Hz) deep brain stimulation of the subthalamic nucleus (STN-DBS), some people with Parkinson's disease (PD) report poorer balance which may contribute to an increased falls risk. However, low-frequency (60 Hz) STN-DBS may improve balance. To better understand the effect of low-frequency STN-DBS, this double-blind randomised crossover study evaluated the acute effects of this therapy on objective measures of balance during standing and gait initiation in people with PD. METHODS: Sixteen post-operative PD patients completed standing, walking and clinical assessments while off medication and receiving high- and low-frequency STN-DBS therapy. Changes in balance were measured using a force plate to provide insight into the effect of stimulation strategy on balance during standing and gait initiation. RESULTS: Linear mixed model analyses indicated that balance during both standing and the locomotion phase of gait initiation was improved with low-frequency STN-DBS, while no difference in the postural phase of gait initiation. These effects were independent of electrode location and total electrical energy delivered. No differences were noted between stimulation conditions for clinical measures of mobility, motor symptom severity, or gait retropulsion. CONCLUSIONS: This study provides evidence for the acute benefits of low-frequency stimulation for improving objective measures of balance during standing and gait initiation in STN-DBS PD patients, independent of DBS electrode contact location. However, the benefits of this alternate therapy may be reduced for patients who experienced significant pre-operative tremor, as low frequency was less effective for managing tremor. TRIAL REGISTRY: Australian New ZealandClinical Trials RegistryURL: www.anzctr.org.au. REGISTRATION NUMBER: ACTRN12618000944235.