Acupuncture at Seven Head Points for Treatment of Posterior Circulation Ischemic Vertigo

INTERVENTION: Acupuncture Group :Main Points: Baihui, Fengchi (bilateral), Naokong (bilateral), Shuigou (bilateral). Technique: Use Hua Tuo brand stainless steel disposable acupuncture needles (F0.32×25mm‐50mm). After routine skin disinfection with 75% alcohol, insert s. Treatment duration is 20 minutes, once daily, with a rest day once a week.;Drug Group : Oral Betahistine Hydrochloride Tablets (4mg per tablet, manufactured by LePu Hengjiuyuan Co., Ltd., Batch No Guoyao Zhunzi H 41022374): 4mg per dose, three times daily, for a total of 2 weeks.; CONDITION: vertigo PRIMARY OUTCOME: Dizziness Handicap Inventory (DHI) ;Dizziness Activities Rating Scale (DARS) ; SECONDARY OUTCOME: hemorheological parameter detection; INCLUSION CRITERIA: Inclusion Criteria 1. Meet the diagnostic criteria for posterior circulation ischemic vertigo according to Western medicine; 2. Meet the diagnostic criteria for posterior circulatschemic vertigo according to Traditional Chinese Medicine; 3. Aged between 20 and 85 years, regardless of gender; 4. Voluntarily participate in this stand sign the informed consent form.