Figure 2

Study sequence. A total of 144 eligible participants will be randomized into one of four treatment groups receiving acupuncture for one minute with different manipulation parameters. Group 1 will receive twirling with a frequency of 60 times per minute toward the contralateral outer canthus at a depth of 0.5 to 0.8 cun. Group 2 will receive twirling with a frequency of 60 times per minute toward the Adam’s apple at a depth of 0.5 to 0.8 cun. Group 3 will receive twirling with a frequency of 120 times per minute toward the contralateral outer canthus at a depth of 0.5 to 0.8 cun. Group 4 will receive twirling with a frequency of 120 times per minute toward the Adam’s apple at a depth of 0.5 to 0.8 cun. The participants will receive 14 acupuncture sessions over 3 to 4 weeks. The subjects will be assessed at two time points: baseline and post-treatment. The primary outcome measurements will include subjective measurements (Vertebrobasilar System Ischemic Neurological Impairment Scale, UCLA Dizziness Questionnaire, Activities of Daily Living Scale, and Psychological and Social Adaptation Scale) and objective measurements (Transcranial Doppler, carotid ultrasonography, and changes in cerebral oxygenation) to reduce bias arising from the placebo effect. We will use metabolomics to investigate the mechanisms underlying the effects of the different manipulation parameters.