Double-Blind Acupuncture Needling: Does Patient Reaction Reveal Needle Authenticity?

Background: Double-blind (practitioner-patient masking) studies were impossible to perform before the introduction of matched acupuncture needles. Their efficacy in conducting double-blind studies is not well known. Objective: To investigate whether patients' reactions during double-blind needle insertion reveal needle authenticity to the practitioner. Design, Setting, and Participants: Thirty healthy volunteers (24 men, 6 women) were needled with a pair of penetrating needles at bilateral TE 5 points. The study was conducted in Tokyo, Japan, in 2002. Main Outcome Measures: The practitioner, who was informed about the possible use of non-penetrating needles, guessed whether the needle was penetrating after each needle removal. He then provided clues to the needle's authenticity and rated his confidence in identification on a numerical rating scale (0-100). Results: Of the 60 penetrating needles, 16 (27%) were correctly identified and 44 (73%) were incorrectly identified by the practitioner. Most identifications were made based on the feeling experienced during needle insertion. Of the 11 needles identified only from the participants' reactions, 7 (6 correctly identified) were based on facial expressions (mean [SD] confidence, 40.0 [11.5]), while 4 (all correctly identified) were based on facial expressions and body movements (62.5 [17.1]). Most identifications based on the participants' reactions and the "feeling of needle insertion" were incorrect. In 1 case, bleeding after needle removal unblinded the needle. Conclusion: There was no significant identification of penetrating vs non-penetrating needles based on participant reactions.