Optimizing Parameters of Transcranial Temporal Interference Stimulation for Spinocerebellar Ataxia Type 3

The purpose of this research study is to identify the optimal biological dose for tTIS that targets DN in SCA3 while achieving the best possible balance between therapeutic efficacy and safety.

Inclusion Criteria: 1. A physician-diagnosed SCA3 according to diagnostic criteria, with definite clinical symptoms and confirmed genetic testing; 2. Age 18-75 years; 3. Baseline total score of SARA: 8-30 points (inclusive); SARA gait function subscore: 2-6 points (inclusive); 4. Willing to participate and provide informed consent; 5. Have a reliable caregiver available; 6. No severe cognitive impairment that would preclude reliable reporting of adverse events or efficacy during treatment. Exclusion Criteria: 1. History of seizures or convulsions, or a seizure within 6 months prior to enrolment; 2. History of severe traumatic brain injury or intracranial neurosurgery; 3. Presence of cardiac pacemakers, cochlear implants, intracranial implanted electronic devices, or other MRI-contraindicated ferromagnetic implants; 4. Severe cognitive impairment (Mini-Mental State Examination \[MMSE\] score ≤ 9) or severe visual, auditory, or speech dysfunction preventing cooperation with scale assessments and study procedures; 5. Pregnant or lactating women, or women of childbearing age not using reliable contraception; 6. Previous neuromodulation treatment (e.g., rTMS or tDCS) within the past year; 7. Skin breakdown or inflammation at the electrode placement site, or known allergy to conductive gel or electrode patch adhesives; 8. Currently participating in other interventional clinical trials, or planning to participate in other trials that might affect the outcome assessment of this study during the study period.