Effect Of Temporal Interference Stimulation On Parkinson's Balance: A Pilot Study

Impaired balance is one of the major symptoms of Parkinson's disease (PD), and related to the damage of the cortico-basal ganglia-thalamo-cortical network. The overactivation of the globus pallidus internus (GPi) was related to the balance impairment of patients. Traditional transcranial electrical stimulation can only modulate the cortex with focality decreasing as depth increasing Temporal interference stimulation (TIs) is a new non-invasive modulation that may target deep brain regions in PD patients. This study investigated how TIs affects PD patients’ balance, and was registered at ClinicalTrials.gov with the identifier ChiCTR2300077258. PURPOSE: To investigate the immediate effect of GP-TIs on balance in PD patients. METHODS: 11 PD patients (H&Y stages 1.5-2.5, age 72 ± 4.43 years, MoCA 27 ± 1.68, UPDRS-III 43 ± 7.86) were recruited in a randomized, cross-over, double-blind design. Participants received TIs (130 Hz) or sham stimulation randomly, with at least one-week interval. A 30-second static balance test (Kistler force plate) conducted during the medication on-period before and after stimulation. A two-way (stimulation × time) repeated measures ANOVA was used to investigate the effect of TIs on dependent variables. RESULTS: In medio-lateral (ML) direction, the trajectory length of the center of pressure (COP) showed a significant time main effect, with a significant decrease (TIs: 12.39 ± 6.76 to 8.99 ± 5.46 vs. sham: 12.00 ± 4.00 to 10.36 ± 6.48) after stimulation (p < 0.05); and the speed of COP showed a decreasing trend (TIs: 371.70 ± 202.94 to 269.63 ± 163.79 vs. sham: 359.87 ± 119.89 to 305.64 ± 196.54, p > 0.05). In antero-posterior (AP) direction, the sample entropy showed an increasing trend (TIs: 0.49 ± 0.19 to 0.56 ± 0.26 vs. sham: 0.45 ± 0.21 to 0.42 ± 0.16, p > 0.05) after TI stimulation. CONCLUSION: Our results indicated that the patients’ balance tended to improve after stimulation, with increased static stability (decreased COP trajectory length and speed) and complexity (increased sample entropy), which supported TIs as a potential alternative for the improvement of balance control of PD patients. Future study should expand the sample size for a more comprehensive investigation.