Electroencephalograph Bicoherence for Assessing the Analgesia of Acupuncture

In the past decades of years the systematic research on pain mechanisms has been the focus of scientists. The traditional Chinese medicine such as acupuncture has shown great potential in pain relief. Transcutaneous Electrical Acupoint Stimulation (TEAS) has been used and bicoherence of EEG has been extracted and used as evaluation criterion of pain relief in the research. In this study 12 volunteers were enrolled and each one received pain stimulation and attended two group experiments, one was transcutaneous electrical stimulation on Hegu acupoint (TEAS), the other was control group (no stimulation). The EEG was recorded and the volume of bicoherence (BIC_V) was extracted, while attended VAS test. The BIC_V increased after pain stimulation, especially in certain cerebral location (Fp1, P3, O1, O2, T6). The BIC_V decreased larger in extent in TEAS group than control group, which has the same change trend with VAS. The study primary proved the efficiency of acupuncture analgesia and BIC_V could be used as an objective assessment criterion of pain perception.