Overview

This prospective, randomized, participant- and outcome-assessor-blinded, parallel-group exploratory trial will compare the target-dependent clinical, neuroimaging, and electrophysiological effects of temporal interference stimulation (TIS) targeting the subthalamic nucleus (STN) or globus pallidus internus (GPi) in patients with Parkinson's disease (PD).

Eighteen participants with idiopathic PD will be randomly assigned in a 1:1 ratio to the STN-TIS or GPi-TIS group. Participants will receive one 20-minute TIS session daily for 7 consecutive days. Motor symptoms will be assessed using the MDS-UPDRS Part III immediately before and after each daily stimulation session. Resting-state functional magnetic resonance imaging (fMRI) and 64-channel electroencephalography (EEG) will be performed before the first stimulation session and immediately after completion of the 7-day intervention.

The primary outcomes are: (1) change in MDS-UPDRS Part III score from Day 1 before stimulation to Day 7 after stimulation; and (2) changes in regional spontaneous brain activity and seed-based functional connectivity measured using resting-state fMRI. Secondary outcomes are: (1) daily immediate changes in MDS-UPDRS Part III scores and the proportion of participants achieving at least 30% improvement at Day 7; and (2) changes in resting-state 64-channel EEG relative bandpower.

Safety and tolerability will be evaluated by monitoring adverse events and local skin reactions throughout the intervention. This study aims to provide preliminary evidence regarding target-dependent functional response patterns associated with STN- and GPi-targeted TIS in PD.

Eligibility

Inclusion Criteria:

1. Adult males or females aged ≥40 years;
2. Diagnosis of idiopathic Parkinson's disease according to the UK Brain Bank criteria, with age of onset ≥40 years;
3. Previous or current treatment with dopamine replacement therapy (e.g., levodopa) with good response;
4. Hoehn and Yahr (H\&Y) stage 1.5-2.5;
5. Able to walk independently for at least 5 minutes without assistive devices;
6. No severe freezing of gait (FOG);
7. Disease duration ≥2 years since diagnosis, clinically stable, and able to comply with study assessments and interventions;
8. Stable medication regimen for at least 4 weeks prior to the study;
9. Signed informed consent form; subject or legal guardian is able to understand and willing to participate in this study.

Exclusion Criteria:

1. Presence of other neurological disorders that may affect the study (e.g., ...);
2. Mild cognitive impairment or above (MoCA ≤23);
3. Orthopedic or other medical conditions that may affect gait or balance;
4. Contraindications to MRI, such as claustrophobia;
5. History of antipsychotic, antidepressant, or other medications that may affect dopamine levels;
6. History of other severe psychiatric disorders;
7. History of epilepsy, traumatic brain injury, or implanted metallic devices in the brain or heart (e.g., stimulators, pacemakers) or other contraindications;
8. History of electroconvulsive therapy (ECT);
9. Currently participating in other gait- or balance-related intervention training;
10. Physician-diagnosed cardiovascular risk factors for exercise.