A Double-Blind Study on Acupuncture Sensations with Japanese Style of Acupuncture: Comparison between Penetrating and Placebo Needles
Table 1
Indices of acupuncture sensations and patient and practitioner blinding for each type of needle.
Penetrating needles
Skin-touch needles
5 mm penetration
10 mm penetration
1 mm skin press
2 mm skin press
Indices of acupuncture sensations
Number of acupuncture sensations elicited
3.8 ± 3.2
5.5 ± 3.3
3.6 ± 2.8
4.9 ± 2.7
MASS index
2.2 (2.6 ± 2.3)
3.6 (4.1 ± 2.6)
1.6 (2.5 ± 2.0)
4.4 (4.4 ± 2.2)
Spreading range
0 (0.6 ± 1.1)
2 (1.3 ± 1.2)
0 (0.4 ± 0.9)
0 (0.7 ± 1.2)
Intensity of needle pain
1.6 (13.5 ± 21.2)
11.5 (24.7 ± 28.7)
0 (8.5 ± 16.9)
24.5 (31.2 ± 29.8)
Blinding assessment
Patient blinding
Confidence in guess
61.6 (61.3 ± 25.1)
70.7 (65.1 ± 27.8)
71.9 (65.8 ± 26.8)
76.8 (70.2 ± 26.2)
Blinding index (95% CI)
0.12 (−0.14 to 0.38)
0.52 (0.29 to 0.75)
0.30 (0.04 to 0.56)
−0.08 (−0.35 to 0.19)
[Blinding status]
[Random guess]
[Unblinded]
[Unblinded]
[Random guess]
Practitioner blinding
Confidence in guess
5.5 (15.8 ± 24.2)
11.0 (30.8 ± 35.9)
6.9 (6.6 ± 2.8)
10.0 (18.9 ± 27.6)
Blinding index (95% CI)
0.02 (−0.16 to 0.20)
0.18 (−0.02 to 0.38)
−0.32 (−0.49 to −0.15)
−0.14 (−0.32 to 0.04)
[Blinding status]
[Random guess]
[Random guess]
[Random guess]
[Random guess]
Note. MASS index, ranges of spreading, intensity of needle pain, and confidence level in needle guesses on 100 mm VAS are expressed in median (mean ± SD); confidences in subjects’ and practitioner’s guesses were calculated without unidentified needles. Unidentified needles (% of each type of 50 needles) by the subjects were 12% for 5 mm penetration, 4% for 10 mm penetration, 2% for 1 mm skin press, and 4% for 2 mm skin press. Unidentified needles (% of each type of 50 needles) by the practitioner were 58% for 5 mm penetration, 46% for 10 mm penetration, 52% for 1 mm skin press, and 58% for 2 mm skin press.
