Tapping-in method (skin penetration technique) with a placebo needle for double-blind acupuncture trials

A systematic review of sham acupuncture validation studies

BACKGROUND

Acupuncture is widely used worldwide; however, studies on its effectiveness have been impeded by limitations regarding the design of appropriate control groups. In clinical research, noninvasive sham acupuncture techniques can only be applied through validation studies. Therefore, this systematic review aimed to evaluate the scope of existing literature on this topic to identify trends.

METHODS

We queried Pubmed, EMBASE, and the Cochrane Central Register of Controlled Trials databases from inception to July 2022 for relevant articles. Author names were used to identify additional relevant articles. Two independent reviewers assessed the identified articles based on the inclusion and exclusion criteria. The following data were extracted: study design, information regarding acupuncturists and participants, general and treatment-related characteristics of the intervention and control groups, participants' experience of acupuncture, and research findings.

RESULTS

The database query yielded 673 articles, of which 29 articles were included in the final review. Among these, 18 involved the use of one of three devices: Streitberger (n = 5), Park (n = 7), and Takakura (n = 6) devices. The remaining 11 studies used other devices, including self-developed needles. All the included studies were randomized controlled trials. The methodological details of the included studies were heterogeneous with respect to outcomes assessed, blinding, and results.

CONCLUSIONS

Sham acupuncture validation studies have been conducted using healthy volunteers, with a focus on blind review and technological developments in sham acupuncture devices. However, theren may be language bias in our findings since we could not query Chinese and Japanese databases due to language barriers. There is a need for more efforts toward establishing control groups suitable for various acupuncture therapy interventions. Moreover, there is a need for more rigorous sham acupuncture validation studies, which could lead to higher-quality clinical studies.

Systematic Review of Acupuncture Placebo Devices with a Focus on the Credibility of Blinding of Healthy Participants And/Or Acupuncturists

Background

An ideal placebo design in clinical research should resemble the intervention under investigation to facilitate blinding, yet remain clinically inert. With regard to physical interventions such as acupuncture, a true placebo device has not been developed and validated. Since 1998, researchers have designed several placebo acupuncture devices (PADs). The three most widely used PADs are the Streitberger, the Park and the Takakura device.

Aim

This review focuses on evaluating studies of these devices, in the context of credibility of blinding (COB), assessment of penetrating pain or sensation, and de qi sensation.

Methods

Electronic database searches were conducted in four English and two Chinese databases from their inception until November 2016. All studies included in the review were conducted on healthy participants and compared verum manual acupuncture with any of the aforementioned PADs with respect to one or more of the above three outcomes related to blinding effect.

Results

The synthesised analyses of the 15 included studies showed that the Streitberger and Park placebo devices may not blind participants successfully when tested at a sensitive acupuncture point (LI4). In terms of penetrating sensation, there were significant differences between these two placebo devices and verum acupuncture when applied at this point. The Takakura device was the only PAD that had the potential to blind the acupuncturist. However, the blinding analyses of all outcome measures were inconsistent.

Conclusion

Overall, there were insufficient data to confirm the blinding effects of these skin-contact PADs as each device was associated with limitations that warrant further design improvements.

Patient blinding with blunt tip placebo acupuncture needles: comparison between 1 mm and 2 mm skin press

OBJECTIVE

To investigate the influence of the depth of skin press in blunt tip placebo acupuncture needles on patient blinding and its relationship to needle diameter.

METHODS

Forty healthy volunteers were enrolled as subjects for patient blinding. Four acupuncturists applied the following needles randomly at three points in each forearm: 0.18 mm and 0.25 mm diameter penetrating needles inserted to a depth of 5 mm, and 0.18 mm and 0.25 mm diameter skin-touch needles depressing the skin at the acupoint to a depth of 1 mm and 2 mm from the skin surface. The subjects reported their guesses at the nature of needles they received, and rated needle pain and de qi. A blinding index was calculated to define the success of blinding for subjects.

RESULTS

The blinding status of subjects for 1 mm press needles of 0.18 mm diameter was "random guess", but "unblinded" for 1 mm press needles of 0.25 mm diameter. For 2 mm press needles of both diameters, the blinding status was "opposite guess" and the blinding status for penetrating needles of both diameters was "unblinded." The percentages of "felt pain" with 2 mm press needles of both diameters were similar to that with penetrating needles, but those were not similar for 1 mm press needles. The frequency of de qi occurrence with 2 mm press needles of 0.18 mm diameter was similar to that of penetrating needles of both diameters.

CONCLUSION

Placebo needles of 2 mm press made more subjects guess that the needles penetrated the skin than 1 mm press needles. The use of small diameter needles increased patient blinding.

A Double-Blind Study on Acupuncture Sensations with Japanese Style of Acupuncture: Comparison between Penetrating and Placebo Needles

To investigate the acupuncture sensations elicited by the Japanese style of acupuncture, penetrating acupuncture and skin-touch placebo needles were randomly administered at various insertion depths (5 and 10 mm for the penetrating needles and 1 and 2 mm for the placebo needles) at LI4 to 50 healthy subjects. Among the 12 acupuncture sensations in the Massachusetts General Hospital Acupuncture Sensation Scale (MASS), “heaviness” was the strongest and most frequently reported sensation with the 10 mm needles, but not with the 5 mm needles. There were no significant differences in number of sensations elicited, MASS index, range of spreading, and intensity of needle pain for 5 mm penetration versus 1 mm skin press and 10 mm penetration versus 2 mm skin press. The MASS index with 2 mm skin-touch needles was significantly larger than that with 1 mm skin-touch and 5 mm penetrating needles. The factor structures in the 12 acupuncture sensations between penetrating and skin-touch needles were different. The acupuncture sensations obtained in this study under satisfactorily performed double-blind (practitioner–patient) conditions suggest that a slight difference in insertion depth and skin press causes significant differences in quantity and quality of acupuncture sensations.

Discrimination accuracy between real and sham press needles in the hands

OBJECTIVES

To evaluate the blinding effectiveness of a modified blunt sham press needle on the basis of the ability of subjects to discriminate between real and sham acupuncture needles compared with their discrimination ability based on pure guessing, and to define differences between senses (touch and vision) in the rates of correctly identified needles.

METHODS

Sixty-three healthy students and staff members were recruited through convenience sampling. First, real or sham acupuncture was randomly administered to the left LI4 point while subjects could not observe the needle tip. A real or sham needle tip was then shown to the subjects. Finally, a random combination of real or sham acupuncture needles were randomly administered to the left and right LI4 points, this time with the subjects observing the procedure. In all conditions the subjects gave their judgement as Yes or No in response to questions asking them to identify the needle type. The proportion of correct judgements (P(C)) was computed for the last part of the trial in left and right LI4 points, and the rates of correctly identified needles for each trial were obtained.

RESULTS

The subjects' accuracy of discrimination between the real and sham acupuncture needles in left and right LI4 points was not significantly different from that based on pure guess (P(C)=0.50 (chance level)), which indicates complete inability to discriminate between needles. The rates of correctly identified needles using touch, vision and a combination of both senses were not significantly different (p=0.807).

CONCLUSIONS

The findings from this study show that this sham acupuncture device successfully blinded subjects to real and sham press needles, suggesting that it is effective for subject blinding in studies on acupuncture using press needles, and facilitating evaluation of the effects of acupuncture in placebo-controlled trials using a rigorous scientific research methodology.

The Potential of Double Blinding with Two Placebo Acupuncture Needles: A Randomized Controlled Pilot-Trial

Background: Whether acupuncture treatment employing multiple penetrating, skin-touch placebo, or no-touch placebo needles designed for double blinding actually do blind practitioners and patients has not been investigated. We aimed to investigate this question. Subjects: 120 patients with functional neck/shoulder stiffness but in otherwise healthy condition were randomly assigned to a treatment using four penetrating, four skin-touch placebo, or four no-touch placebo needles. Each of six acupuncturists applied four needles to four acupoints in the neck/shoulder of 20 patients. Acupuncturists and patients were asked to guess the treatment mode and their confidence in their guesses on 100 mm visual analog scales. Results: The kappa coefficients between practitioner guesses and treatment type and between patient guesses and treatment type were 0.15 and 0.44, respectively. The median score of practitioner confidence was 46.8, and no significant difference in confidence between correct and incorrect guesses was revealed for any treatment. The median score of patient confidence for correct guesses was 77.6. The kappa coefficient between practitioner and patient guesses was 0.06. Conclusions: The practitioners were blinded to the nature of treatment using the same multiple needles, but patient blinding was insufficient. Further improvement is necessary to achieve satisfactory patient blinding with these acupuncture needles.

Effect of blinding with a new pragmatic placebo needle: a randomized controlled crossover study

Placebo control is a useful method for determining the efficacy of a therapy. In acupuncture researches, the preferred method for placebo control is acupuncture using a placebo needle that has a blunt tip and achieves no skin penetration. We performed a crossover study to validate the blinding effect of a new type of placebo needle. Sixty volunteers were randomized to receive acupuncture using 2 types of needles with different sequences: sequence AB, involving first the pragmatic placebo needle and then the real needle, and sequence BA, in a reverse order. Placebo acupuncture was performed by administering the placebo needle through an adhesive pad without skin penetration on the acupoints LI4, RN12, BL25, and BL36. Real acupuncture was performed by needling through the pad and penetrating the skin to 15 mm using a real needle on the same acupoints. The acupuncture was administered every other day with 3 sessions for 1 type of needle. The primary outcome was the perception of needle penetration. Besides degree of acupuncture pain, type, and degree of needle sensation, needle acceptability and factors influencing the subject blinding effect were assessed. Needle penetration was felt by 100%, 90% (54/60), 88.3% (53/60), and 95% (57/60) of volunteers receiving placebo acupuncture and 98.3% (59/60), 96.7% (58/60), 95% (57/60), and 95% (57/60) of volunteers receiving real acupuncture on LI4, RN12, BL25, and BL36, respectively. Differences of the volunteers' perception of needle penetration between the placebo needle and real needle were not significant for the 4 acupoints (all P > 0.05). Volunteers experienced fewer distension sensations (P = 0.01), a lower degree of needle sensation (P = 0.007), and less pain (P = 0.006) during placebo acupuncture than during real acupuncture. The placebo needle was more easily accepted than the real needle (OR = 1.63, 95% CI, 1.01-2.64). The influences of age, sex, educational level, acupuncture experience, needle sensation, acupuncture pain, and needle acceptability on volunteers' perception of needle penetration were not significant. The pragmatic placebo needle is a valid control for acupuncture research. It produces a good subject blinding effect with a similar appearance to conventional acupuncture needles and no skin penetration when applied.

Electroacupuncture at points Baliao and Huiyang (BL35) for post-stroke detrusor overactivity

Acupuncture is used extensively in China for the treatment of stroke and other neurological disorders. The National Institutes of Health recommends acupuncture as an adjunctive therapy for stroke recovery. This study included patients with post-stroke detrusor overactivity who were treated in the Department of Neurology, Fourth Hospital of Harbin Medical University, China. Subjects received either electroacupuncture or sham electroacupuncture at points Baliao [including bilateral Shangliao (BL31), bilateral Ciliao (BL32), bilateral Zhongliao (BL33), and bilateral Xialiao (BL34)] and Huiyang (BL35). Our results showed that electroacupuncture significantly improved cystometric capacity and bladder compliance, decreased detrusor leak point pressure, ameliorated lower urinary tract symptoms, and decreased the risk of upper urinary tract damage. These findings indicate that electroacupuncture at points Baliao and Huiyang is an effective treatment for post-stroke detrusor overactivity.

Design of a randomised acupuncture trial on functional neck/shoulder stiffness with two placebo controls

Background

Functional neck/shoulder stiffness is one of the most well-known indications for acupuncture treatment in Japan. There is little evidence for the effectiveness of acupuncture treatment for functional neck/shoulder stiffness. Research using two different placebos may allow an efficient method to tease apart the components of real acupuncture from various kinds of ‘non-specific’ effects such as ritual with touch or ritual alone. Herein, we describe a protocol of an ongoing, single-centre, randomised, placebo-controlled trial which aims to assess whether, in functional neck/shoulder stiffness, acupuncture treatment with skin piercing has a specific effect over two types of placebo: skin-touching plus ritual or ritual alone.

Methods

Six acupuncturists and 400 patients with functional neck/shoulder stiffness are randomly assigned to four treatment groups: genuine acupuncture penetrating the skin, skin-touch placebo or no-touch placebo needles in a double-blind manner (practitioner-patient blinding) or no-treatment control group. Each acupuncturist applies a needle to each of four acupoints (Bladder10, Small Intestine14, Gallbladder21 and Bladder42) in the neck/shoulder to 50 patients. Before, immediately after and 24 hours after the treatment, patients are asked about the intensity of their neck/shoulder stiffness. After the treatment, practitioners and patients are asked to guess whether the treatment is “penetrating”, “skin-touch” or “no-touch” or to record “cannot identify the treatment”.

Discussion

In addition to intention-to-treat analysis, we will conduct subgroup analysis based on practitioners’ or patients’ guesses to discuss the efficacy and effectiveness of treatments with skin piercing and various placebo controls. The results of practitioner and patient blinding will be discussed. We believe this study will further distinguish the role of different components of acupuncture.

Trial registration

Current Controlled Trial ISRCTN76896018