Double blinding with a new placebo needle: a validation study on participant blinding
- 1Department of Acupuncture and Moxibustion, Faculty of Health Sciences, Tokyo Ariake University of Medical and Health Sciences, The Educational Foundation of Hanada Gakuen, Tokyo, Japan
- 2Second Department of Physiology, Showa University School of Medicine, Tokyo, Japan
- 3The Foundation for Oriental Medicine Research, Tokyo, Japan
- 4Japan School of Acupuncture, Moxibustion and Physiotherapy, The Educational Foundation of Hanada Gakuen, Tokyo, Japan
- Correspondence to Dr Nobuari Takakura, Department of Acupuncture and Moxibustion, Faculty of Health Sciences, Tokyo Ariake University of Medical and Health Sciences, 2-9-1 Ariake, Koto-ku, Tokyo 135-0063, Japan;
Contributors NT designed the double-blind needles and the study, performed the data collection and analysis and wrote the manuscript. MT, AK and HY participated in the study design, the data collection and analysis and manuscript preparation. NT is the guarantor.
- Accepted 7 February 2011
- Published Online First 13 March 2011
Background A no-touch control needle in which the needle tip cannot reach the skin has been designed, and has been validated for practitioner blinding in a previous study but not for participant blinding.
Objective To test whether the no-touch control needle can effectively blind subjects.
Methods An acupuncturist applied, in turn, a no-touch control, skin-touch placebo and penetrating needle in one forearm of 80 healthy subjects. After removing each needle, the subjects were asked to judge the type of needle and rate the sensation of skin penetration/penetration-like or skin pressure/pressure-like pain on a 100 mm visual analogue scale.
Results The subjects correctly identified 67% of needles overall. 17 of the 80 no-touch control needles were judged as skin-touch, and one as penetrating. In addition, six skin-touch placebo needles, and no penetrating needles, were judged as no-touch. Half of the 80 skin-touch placebo needles and 65 of the 80 penetrating needles and two no-touch control needles elicited pain. Of 240 needles, the practitioner identified 120 correctly that did not fit the probability of 1/3 (χ2=30.00, p<0.01).
Conclusions The no-touch control needles may be used as a blind control for the acupuncture procedure, or to test the physiological effect of the skin-touch needles, but are not suitable for double-blind testing of the needle effect.
Funding The Educational Foundation of Hanada Gakuen, 20-1 Sakuragaoka-machi, Shibuya-ku, Tokyo 150-0031, Japan.
Competing interests NT and the Educational Foundation of Hanada Gakuen possess a US patent 6575992B1, a Canadian patent CA 2339223, a Korean patent 0478177, a Taiwanese patent 150135, a Chinese patent ZL00800894.9 (Title: Safe needle, placebo needle and needle set for double blind) and a Japanese patent 4061397 (Title: Placebo needle, and needle set for double-blinding) on the needles described in this manuscript. NT is a salaried employee of the Educational Foundation of Hanada Gakuen and has received research funding from the Educational Foundation of Hanada Gakuen.
Patient consent Obtained.
Ethics approval This study was conducted with the approval of the ethics committee of the Showa University School of Medicine.
Provenance and peer review Not commissioned; externally peer reviewed.