Intermittent theta-burst stimulation of right putamen improves motor scores in Parkinson's disease patients.

Transcranial temporal interference stimulation (tTIS) is a non-invasive method designed to target deep brain regions, such as the basal ganglia, without affecting overlying cortical areas. This study investigated intermittent theta-burst (iTBS) tTIS effects on symptom severity in Parkinsons disease (PD) and motor learning behavior, a condition associated with, among others, basal ganglia dysfunction. We hypothesized that iTBS tTIS applied to the right putamen would alleviate PD symptoms and improve motor learning expressed by the contra-lateral hand. This randomized, double-blinded, crossover trial included 19 PD patients (mean age 64 years, 14 males) and 19 age- and sex-matched healthy controls (mean age 68.6 years). Structural MRI data were obtained for each participant, and individualized electric field simulations were performed to predict field strength in the right putamen. The motor part of the Movement Disorder Societys Unified Parkinsons Disease Rating Scale (MDS UPDRS III) served as a primary outcome parameter, an alternating finger tapping task (aFTT) and Motor learning assessed through a sequential finger-tapping tasks (sFTT) were secondary outcome parameters. ITBS tTIS significantly reduced MDS UPDRS motor scores in PD patients and the stimulation induced changes in motor performance correlated with the electric field strength in the targeted putamen region. No effect was found for motor performance or motor learning in neither of the groups. These findings indicate that iTBS-tTIS in general holds potential as a non-invasive approach for deep brain stimulation in PD.