Transcutaneous Electrical Acupoint Stimulation on Postoperative Dizziness in Hemifacial Spasm Patients

Inclusion Criteria: * American Society of Anesthesiologists (ASA) physical status: I-III * Body mass index (BMI): 18-30 * Diagnosed of hemifacial spasm * Undergoing microvascular decompression surgery Exclusion Criteria: * Pregnant or lactating women * Poorly controlled hypertension or poorly controlled diabetes, severe cardiovascular and cerebrovascular diseases and mental illness * Cardiac pacemakers * Scars on bilateral Neiguan acupoints or on the mastoid area * Upper limb nerve injury * Raynaud's syndrome * Motion sickness or PONV history * Eye diseases (glaucoma, cataracts, eye trauma, etc.) or previous eye surgery * Participate in other clinical trials