In the American study, fifty-two children were randomised to receive an acupressure bead placed either at Yintang (M-HN-3) or at a sham point above the left eyebrow. Children in the Yintang group were found to have experienced reduced anxiety during the 30 minute pre-operative waiting period, whereas those in the sham group experienced increased anxiety (-9% vs +2%). The acupressure intervention had no measurable effect on levels of consciousness during anaesthesia (measured by bispectral index monitoring), nor on requirements for anaesthetic during the procedure. (Extra-1 acupressure for children undergoing anesthesia. Anesth Analg. 2008 Sep;107(3):811-6).