Double blinding with a new placebo needle: a further validation study
- Nobuari Takakura1,2,3,4,
- Miho Takayama1,2,3,4,
- Akiko Kawase1,2,3,4,
- Ted J Kaptchuk5,
- Hiroyoshi Yajima1,2,3,4
- 1Department of Acupuncture and Moxibustion, 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
- 5Osher Research Institute, Harvard Medical School, Boston, Massachusetts, USA
- Correspondence to Professor 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; takakura{at}t-ariake.ac.jp
-
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. TJK reviewed in the preparation of the revised paper. NT is the guarantor.
- Accepted 12 March 2010
- Published Online First 7 June 2010
Abstract
Background The masking properties of a new, non-penetrating, double-blind placebo acupuncture needle were demonstrated. Practitioners correctly identified some of the needles; if they were confident in this opinion, they would be unblinded.
Objective To investigate the clues that led to correct identification, and the confidence in this decision.
Methods Ten acupuncture practitioners, blindly and randomly, applied 10 each of three types of needle to the shoulder: blunt, non-penetrating needles that pressed the skin (‘skin-touch placebo needle’); new non-penetrating needles that penetrated soft material (stuffing) but did not reach the skin (‘non-touch control needle’); matching penetrating needles. Afterwards, practitioners were asked to judge the type of needle, their confidence in their decision and what clues led them to their judgements.
Results Of the 30 judgements made by each practitioner, the mean number of correct, incorrect and unidentifiable answers were 10.4 (SD 3.7), 15.2 (SD 4.9) and 4.4 (SD 6.1), respectively. There was no significant difference in the confidence scores for 104 correct (mean, 54.0 (SD 20.2)%) and 152 incorrect (mean, 50.3 (SD 24.3)%) judgements. Twelve needles were identified with 100% confidence—three correct, and nine incorrect. For needles correctly identified, the proportions of non-touch (p = 0.14) and skin-touch (p = 0.17), needles were no greater than chance, but the proportion of penetrating needles correctly identified exceeded chance (p < 0.01). 53% of judgements were made from the “feeling of needle insertion”, but 57% of these were wrong.
Conclusion Practitioners had a slight tendency to guess the penetrating needles correctly, but were uncertain about most of their judgments, posing only a very small risk to double blinding.
Footnotes
-
Funding The work of TJK was supported by NCCAM-NIH grant # K24 AT004095.
-
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 Taiwan 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 Showa University School of Medicine.
-
Provenance and peer review Not commissioned; externally peer reviewed.
- Accepted 12 March 2010
- Published Online First 7 June 2010
